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201310th Annual Report
ISSN 2054-183X (Online)
HIPS
KNEES
ANKLES
ELBOWS
SHOULDERS
PROMs
National Joint Registry for England, Wales and Northern IrelandSurgical data to 31 December 2012
Prepared by
The NJR Editorial Board
NJRSC MembersMr Martyn Porter (Chairman)Mick BorroffProfessor Paul GreggProfessor Alex MacGregorMr Keith Tucker
NJR RCC Network RepresentativesMr Peter Howard (Chairman)Mr Colin EslerMr Alun JohnMr Matthew Porteous
Orthopaedic SpecialistsProfessor Andy CarrMr Andy Goldberg
NJR Research FellowsMr Jeya Palan
Healthcare Quality Improvement PartnershipNJR Management Team and NJR CommunicationsRebecca BeaumontJames ThorntonMelissa WrightElaine Young
Northgate Information Solutions (UK) LtdNJR Centre, IT and data managementOlivia ForsythAnita MistryDr Claire NewellDr Martin PickfordMartin RoyallMike Swanson
University of BristolNJR Statistical support, analysis and research teamProfessor Yoav Ben ShlomoProfessor Ashley BlomDr Emma ClarkProfessor Paul DieppeDr Linda HuntDr Michèle SmithProfessor Jonathan TobiasKelly Vernon
Pad Creative Ltd (design and production)
This document is available in PDF format for download from the NJR website at www.njrcentre.org.uk
This document is available in PDF format for download from the NJR website at www.njrcentre.org.uk
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
3www.njrcentre.org.uk
Contents
Chairman’s introduction 10
Foreword from the Chairman of the Editorial Board 12
Executive summary 13
Part 1: Annual progress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Part 2: Clinical activity 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Part 3: Outcomes after joint replacement 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Part 1 Annual progress 23
1.1 Introduction 23
1.1.1 The National Joint Registry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .241.1.2 Management and funding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .241.1.3 Content of the 10th Annual Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
1.2 Data completeness and quality 26
1.2.1 Key indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .271.2.2 Operation totals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
1.3 Work of the NJR Steering Committee and its Sub-committees 33
1.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .341.3.2 NJR Steering Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 1.3.3 NJR Editorial Board - Mr Martyn Porter, Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .351.3.4 Implant Performance Sub-committee - Mr Keith Tucker, Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .361.3.5 Surgeon Outliers Sub-committee - Professor Paul Gregg, Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .361.3.6 NJR Research Sub-committee - Professor Alex MacGregor, Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . . .381.3.7 NJR Data Quality Group - Professor Paul Gregg, Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .391.3.8 NJR Regional Clinical Coordinators’ (RCC) Network - Mr Peter Howard, Chairman . . . . . . . . . . . . . . . . . . . .40
1.4 Highlights 41
1.4.1 Geographic extension of the NJR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .421.4.2 Extension of the NJR: Elbows and shoulders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .421.4.3 Beyond Compliance: ‘Protecting Patients, Supporting Innovation’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .421.4.4 Publication of consultant-level data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .441.4.5 Patient-focused initiatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .441.4.6 NJR Feedback Services: Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .441.4.7 Proposed changes to the Minimum Dataset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .451.4.8 Price Benchmarking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .451.4.9 International developments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .461.4.10 Patient Reported Outcomes Measures (PROMs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .461.4.11 NJR Fellowships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 1.4.12 Orthopaedic Data Evaluation Panel (ODEP) overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
1.5 Finance 48
1.5.1 Income and expenditure 2012/13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49Appendix 1 NJR Steering Committee 2012/13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
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Appendix 2 List of papers, publications and research requests using NJR data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52Appendix 3 Additional information on the NJR website . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Part 2 Clinical activity 2012 56
2.1 Introduction 56
2.1.1 Hospitals and treatment centres participating in the NJR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
2.2 Hip replacement procedures 2012 60
2.2.1 Primary total hip replacement procedures (THR) 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .622.2.2 Hip revision procedures 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
2.3 Knee replacement procedures 2012 84
2.3.1 Primary knee replacement procedures 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .862.3.2 Knee revision procedures 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
2.4 Ankle replacement procedures 2012 103
2.4.1 Primary ankle replacement procedures 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1042.4.2 Ankle revision procedures 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109
2.5 Elbow replacement procedures 2012 111
2.5.1 Primary elbow replacement procedures 2012 (nine months) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1122.5.2 Elbow revision procedures 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1152.5.3 Elbow components used in primary and revision procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
2.6 Shoulder replacement procedures 2012 117
2.6.1 Primary shoulder replacement procedures 2012 (nine months) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1182.6.2 Shoulder components used in primary procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1212.6.3 Shoulder revision procedures 2012 (nine months) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121
Part 3 Outcomes after joint replacement 2003 to 2012 123
3.1 Summary of data sources and linkage 123
3.2 Outcomes after primary hip replacement 126
3.2.1 Overview of primary hip surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1283.2.2 Revisions after primary hip surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1313.2.3 Revisions for different causes after primary hip surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1363.2.4 Revisions after primary hip surgery for the main stem-cup brand combinations . . . . . . . . . . . . . . . . . . . . . .1403.2.5 Revisions after primary hip surgery: Effect of head sizes for polyethylene liners . . . . . . . . . . . . . . . . . . . . . .1443.2.6 Mortality after primary hip surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1483.2.7 In-depth study: Metal-on-metal hip resurfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1503.2.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .158
3.3 Outcomes after primary knee replacement 159
3.3.1 Overview of primary knee surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1603.3.2 Revisions after primary knee surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1653.3.3 Revisions for different causes after primary knee surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
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3.3.4 Revisions after primary knee surgery by main brands for TKR and UKR . . . . . . . . . . . . . . . . . . . . . . . . . . . .1733.3.5 Mortality after primary knee surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1793.3.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .181
3.4 Outcomes after primary ankle replacement 182
3.4.1 Overview of primary ankle surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1833.4.2 Revisions after primary ankle surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1843.4.3 Mortality after primary ankle surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184
3.5 PROMs outcomes 186
3.5.1 Background to Patient Reported Outcome Measures (PROMs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1873.5.2 Data linkage from PROMs to HES to NJR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1873.5.3 PROMs outcomes for primary hip replacements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1883.5.4 PROMs outcomes for primary knee replacements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1963.5.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201
Part 4 Trust-, Local Health Board- and unit-level activity and outcomes 2012 202
4.1 Introduction 202
4.2 Unit outlier analysis methodology 204
Trust-, Local Health Board- and unit-level data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .206
Part 1 tablesTable 1.1 Total joint replacement procedures entered into the NJR, 2008/09 to 2012/13, recorded by country in which the procedure took place. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29Table 1.2 Total joint replacement procedures entered into the NJR, 2008/09 to 2012/13, recorded by procedure type 30Table 1.3 Proportion of reported procedures by type of provider, 2008/09 to 2012/13. . . . . . . . . . . . . . . . . . . . . . . . .31
Part 1 figuresFigure 1.1 Compliance, Consent, and Linkability Rates from 2003 to 2013. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28Figure 1.2 Beyond Compliance data flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Part 2 tablesTable 2.1 Total number of hospitals and treatment centres in England and Wales able to participate in the NJR and the proportion actually participating in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58Table 2.2 Number of participating hospitals, according to number of procedures performed during 2012 . . . . . . . . . . .58Table 2.3 Procedure details, according to type of provider for hip procedures in 2012. . . . . . . . . . . . . . . . . . . . . . . . . .61Table 2.4 Patient characteristics for primary hip replacement procedures in 2012, according to
procedure type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64Table 2.5 Age and gender for primary hip replacement patients in 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65Table 2.6 Indications for hip primary procedure based on age groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66Table 2.7 Surgical technique for primary hip replacement patients in 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
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Table 2.8 Thromboprophylaxis regime for primary hip replacement patients, prescribed at time of operation . . . . . . . . . .73Table 2.9 Reported untoward intra-operative events for primary hip replacement patients in 2012,
according to procedure type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73Table 2.10 Patient characteristics for hip revision procedures in 2012, according to procedure type . . . . . . . . . . . . . . . .81Table 2.11 Indication for surgery for hip revision procedures 2008 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82Table 2.12 Components removed during hip revision procedures in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82Table 2.13 Components used during single-stage hip revision procedures in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83Table 2.14 Procedure details, according to type of provider for knee procedures in 2012 . . . . . . . . . . . . . . . . . . . . . . . . .85Table 2.15 Patient characteristics for primary knee replacement procedures in 2012, according to procedure type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87Table 2.16 Age and gender for primary knee replacement patients in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91Table 2.17 Characteristics of surgical practice for primary knee replacement procedures in 2012, according to procedure type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95Table 2.18 Thromboprophylaxis regime for primary knee replacement patients, prescribed at time of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97Table 2.19 Reported untoward intra-operative events for primary knee replacement patients in 2012, according to procedure type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98Table 2.20 Patient characteristics for knee revision procedures in 2012, according to procedure type . . . . . . . . . . . . .102Table 2.21 Patient characteristics for primary ankle replacement procedures in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . .105Table 2.22 Age and gender for primary ankle replacement patients in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106Table 2.23 Characteristics of surgical practice for primary ankle replacement procedures in 2012. . . . . . . . . . . . . . . . .107 Table 2.24 Thromboprophylaxis regime for primary ankle replacement patients, prescribed at time of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108Table 2.25 Reported untoward intra-operative events for primary ankle replacement patients in 2012 . . . . . . . . . . . . . .108Table 2.26 Details for ankle revision procedures in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109 Table 2.27 Patient characteristics for ankle revision procedures in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110Table 2.28 Details for replacement primary elbow procedures in 2012 (nine months) . . . . . . . . . . . . . . . . . . . . . . . . . .112Table 2.29 Patient characteristics of primary elbow replacement procedures in 2012 (nine months) . . . . . . . . . . . . . . .113Table 2.30 Characteristics of surgical practice for primary elbow replacement procedures in 2012 (nine months). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114Table 2.31 Thromboprophylaxis regime for primary elbow replacement patients, prescribed at time of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Table 2.32 Details for elbow revision procedures in 2012 (nine months). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116Table 2.33 Details for primary shoulder procedures in 2012 (nine months).. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118Table 2.34 Patient characteristics for primary shoulder procedures in 2012 (nine months). . . . . . . . . . . . . . . . . . . . . . .119 Table 2.35 Characteristics of surgical practice for primary shoulder replacement procedures in 2012 (nine months) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 Table 2.36 Thromboprophylaxis regime for primary shoulder replacement patients, prescribed at time of operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121 Table 2.37 Details for shoulder revision procedures in 2012 (nine months). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .122
Part 2 figuresFigure 2.1 Percentage of participating hospitals by number of procedures per annum, 2004 to 2012 . . . . . . . . . . . . .59Figure 2.2 Primary hip procedures by type of provider 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62Figure 2.3 Type of primary hip replacement procedures undertaken between 2005 and 2012. . . . . . . . . . . . . . . . . . . . .63Figure 2.4 Age and gender for primary hip replacement patients in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67Figure 2.5 Age for primary hip replacement patients between 2003 and 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68Figure 2.6 ASA grades for primary hip replacement patients between 2003 and 2012 . . . . . . . . . . . . . . . . . . . . . . . . . .69Figure 2.7 BMI for primary hip replacement patients between 2004 and 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70Figure 2.8 Bone cement types for primary hip replacement procedures undertaken between 2004 and 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
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Figure 2.9 Top five cemented hip stem brands, trends 2003 to 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75Figure 2.10 Top five cemented hip cup brands, trends 2003 to 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75Figure 2.11 Top five cementless hip stem brands, trends 2003 to 2012.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76Figure 2.12 Top five cementless hip cup brands, trends 2003 to 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77Figure 2.13 Top five resurfacing head brands, trends 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78Figure 2.14 Femoral head size, trends 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79Figure 2.15 Hip articulation, trends 2003 to 2012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79Figure 2.16 Primary knee procedures by type of provider 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86Figure 2.17 Type of primary knee replacement procedures undertaken between 2006 and 2012. . . . . . . . . . . . . . . . . . .88Figure 2.18 Implant constraint for bicondylar primary knee replacement procedures between 2006 and 2012 . . . . . . . . . 89Figure 2.19 Bearing type for unicondylar implant used in primary knee replacement procedures undertaken between 2006 and 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90Figure 2.20 Age and gender for primary knee replacement patients in 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92Figure 2.21 ASA grades for primary knee replacement patients between 2003 and 2012 . . . . . . . . . . . . . . . . . . . . . . . . .93Figure 2.22 BMI for primary knee replacement patients between 2004 and 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94Figure 2.23 Bone cement types for primary knee replacement procedures undertaken between 2003 and 2012 . . . . .96Figure 2.24 Top five total condylar knee brands, trends 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98Figure 2.25 Top five unicondylar knee brands, trends 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99Figure 2.26 Top five patello-femoral knee brands, trends 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100Figure 2.27 Top five fixed hinged knee brands, trends 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101
Part 3 tablesTable 3.1 Summary description of datasets used for survivorship analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124Table 3.2 Composition of person-level datasets for survivorship analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125Table 3.3 Numbers (%) of primary hip replacements by fixation and, within each fixation sub-group, by bearing surface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128Table 3.4 Percentage of primary hip replacements performed each year by type of hip fixation and constraint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129Table 3.5 Distribution of consultant surgeon and unit caseload for each fixation type . . . . . . . . . . . . . . . . . . . . . . . . .130Table 3.6 Age (in years) at primary hip replacement, by fixation and main bearing surface . . . . . . . . . . . . . . . . . . . . . .131Table 3.7 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI), at different times after the primary operation, for each fixation/bearing surface sub-group . . . . . . . . . . . . . .132Table 3.8 Revision rates (95% CI), expressed as number of revisions per 1,000 patient-years, for each recorded reason for first hip revision. Rates shown are for all revised cases and by fixation and bearing surface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137Table 3.9 Revision rates, expressed as numbers per 1,000 patient-years, for any reason, according to time interval from primary operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139Table 3.10 Revision rates (95% CI), expressed as numbers per 1,000 patient-years, for each reason, by time interval from primary operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139Table 3.11 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) at different times after the primary operation, for cup-stem brand combinations with large group sizes (>2,500 or >1,000 in the case of resurfacings) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141Table 3.12 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) at different times after the primary operation for cup-stem brand combinations with large group sizes (>10,000) with further subdivision by main bearing surface (provided the sub-group size >1,000). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143Table 3.13 Kaplan-Meier estimates of the cumulative percentage mortality (95% CI), at different times after primary hip operation, for all cases and by age/gender. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149Table L1 Description of comparison groups: number of cases (percentage of total).. . . . . . . . . . . . . . . . . . . . . . . . . .154Table L2 Predicted revision rates for 55-year-old males by prosthesis and head size (95% CI) . . . . . . . . . . . . . . . . . .155
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Table L3 Predicted revision rates for 55-year-old females by prosthesis and head size (95% CI). . . . . . . . . . . . . . . . .155Table L4 Comparison of most commonly used brands; predicted revision rates for 55-year-old patients (95% CI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156Table L5 Reasons for revision (95% CI), expressed as incidence per 1,000 patient-years, by articulation and fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157Table 3.14 Numbers and percentages of primary knee replacements by fixation method and bearing type . . . . . . . . . .161 Table 3.15 Percentage of primary knee replacements performed each year by method of fixation and, within each fixation group, by bearing type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162Table 3.16 Distribution of consultant surgeon and unit caseload for each fixation type . . . . . . . . . . . . . . . . . . . . . . . . .163Table 3.17 Age (in years) at primary operation for different types of knee replacement; by fixation and bearing type . . .164Table 3.18 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) at specified
times after primary knee replacement, by fixation and bearing type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166Table 3.19 Revision rates (95% CI), expressed as number of revisions per 1,000 patient-years, for each recorded
reason for first knee revision. Rates shown are for all revised cases and by fixation type . . . . . . . . . . . . . . .170Table 3.20 Revision rates (95% CI), expressed as number of revisions per 1,000 patient-years, for each recorded
reason for first knee revision. Rates shown are for each fixation/bearing surface sub-group . . . . . . . . . . . . .171Table 3.21 Kaplan-Meier estimated cumulative percentage probability of first revision (95% CI) of a primary total knee
replacement by main type of implant brand at the indicated number of years after primary operation) . . . . .174Table 3.22 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) of a
primary unicompartmental knee replacement by main type of implant brand at the indicated number of years after primary operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175
Table 3.23 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) of a total knee replacement at the indicated number of years after primary operation, by main implant brands and type of fixation and constraint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .176
Table 3.24 Age and gender distribution of patients undergoing all types of primary knee replacement operations for the period 2003 to 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179
Table 3.25 Kaplan-Meier estimated cumulative percentage probability (95% CI) of a patient dying at the indicated number of years after a primary knee joint replacement operation (i) by age group and gender and (ii) for all patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180
Table 3.26 Number of primary ankle operations by year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183Table 3.27 Number of primary ankles by ankle brand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183Table 3.28 Reasons for ankle revision (not mutually exclusive) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184Table 3.29 Overall outcomes after primary hip surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189Table 3.30 Bias in Q2 completion of EQ-5D Index, EQ-5D Health Scale (VAS), Oxford Hip Score . . . . . . . . . . . . . . . . .190Table 3.31 Changes in EQ-5D Index for hip primaries with index scores at both time points . . . . . . . . . . . . . . . . . . . . .190Table 3.32 Changes in EQ-5D Health Scale Score (VAS) for hip primaries with scores at both time points . . . . . . . . . .192Table 3.33 Changes in Oxford Hip Score for hip primaries with scores at both time points . . . . . . . . . . . . . . . . . . . . . .193Table 3.34 Overall outcomes after primary knee surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196Table 3.35 Bias in Q2 completion of EQ-5D Index, EQ-5D Health Scale (VAS), Oxford Knee Score . . . . . . . . . . . . . . . .197Table 3.36 Changes in EQ-5D Index for knee primaries with index scores at both time points . . . . . . . . . . . . . . . . . . . .198Table 3.37 Changes in EQ-5D Health Scale score (VAS) for knee primaries with scores at both time points . . . . . . . . .198Table 3.38 Changes in Oxford Knee Score for knee primaries with scores at both time points . . . . . . . . . . . . . . . . . . .198
Part 3 figuresFigure 3.1 Patients with hip, knee and ankle primary operations within the survivorship data sets . . . . . . . . . . . . . . . . .125Figure 3.2 Comparison of cumulative hazard of first revision for cemented hips with different bearing
surfaces (with 95% CI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133Figure 3.3 Comparison of cumulative hazard of first hip revision for uncemented hips with different
bearing surfaces (with 95% CI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
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Figure 3.4 Comparison of cumulative hazard of a first hip revision for hybrid (not including reverse hybrid) hips with different bearing surfaces (with 95% CI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
Figure 3.5 (i) Comparison of the cumulative hazard for revision for different head sizes for metal-on-polyethylene monobloc cup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145
Figure 3.5 (ii) Comparison of the cumulative hazard for revision for different head sizes for metal-on-polyethylene with metal shell/polyethylene liners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146
Figure 3.5 (iii) Comparison of the cumulative hazard for revision for different head sizes for ceramic-on-polyethylene with polyethylene monobloc cup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147
Figure 3.5 (iv) Comparison of the cumulative hazard for revision for different head sizes for ceramic-on-polyethylene with metal shell/polyethylene liners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148
Figure L1 Cumulative hazard of revision after resurfacing by gender (with 95% CI). . . . . . . . . . . . . . . . . . . . . . . . . . . .152Figure L2 Estimated cumulative incidence of revision for 55-year-old male by prosthesis type . . . . . . . . . . . . . . . . . . .153Figure L3 Estimated cumulative incidence of revision for 55-year-old female by prosthesis type . . . . . . . . . . . . . . . . . .153Figure 3.6 Cumulative hazard (x100) of a first revision for different types of primary knee replacement at
increasing years after the primary surgery (with 95% CI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168Figure 3.7 Comparison of the cumulative hazard (x100) of a knee prosthesis first revision for different
bearing types at increasing years after the primary surgery when the primary arthroplasty method of fixation was cemented only (with 95% CI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .169
Figure 3.8 (i) Histogram to compare the distributions of the EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=80,394). At Q1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194
Figure 3.8 (ii) Histogram to compare the distributions of the EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=80,394). At Q2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194
Figure 3.9 (i) Histogram to compare the distributions of the Oxford Hip Score between Q1 and Q2 in cases with scores at both time points (n=92,133). At Q1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
Figure 3.9 (ii) Histogram to compare the distributions of the Oxford Hip Score between Q1 and Q2 in cases with scores at both time points (n=92,133). At Q2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195
Figure 3.10 (i) Histogram to compare the distributions of EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=84,031). At Q1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199
Figure 3.10 (ii) Histogram to compare the distributions of EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=84,031). At Q2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199
Figure 3.11 (i) Histogram to compare the distributions of the Oxford Knee Score between Q1 and Q2 in cases with scores at both time points (n=93,353). At Q1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200
Figure 3.11 (ii) Histogram to compare the distributions of the Oxford Knee Score between Q1 and Q2 in cases with scores at both time points (n=93,353). At Q2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200
GlossaryGlossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
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It has been another busy year for the National Joint Registry (NJR), which continues to develop and mature as the world’s largest orthopaedic registry and show leadership in analysis and communication of insights we glean from our rich pool of data. Normally my ‘thanks to colleagues’ goes at the end of the Chairman’s Introduction, but given the extraordinary efforts and change we have seen this year, I want to acknowledge up-front my gratitude to the NJR Steering Committee, and in particular to note the outstanding contributions made by our Vice Chairman, Professor Paul Gregg, Mr Martyn Porter, Mr Keith Tucker, Professor Alex MacGregor and Mr Peter Howard. Without their commitment and generosity of time and spirit, much of the work of the NJR would not have been possible. I would also like to thank our partners: University of Bristol, led by Professor Ashley Blom; Northgate Information Solutions; as well as the NJR management team at the Healthcare Quality Improvement Partnership, led by Elaine Young, who receives our special thanks for her dedication and hard work.
Historically, the data collection and analysis done by the NJR has focused on hip and knee replacement, and from April 2010 ankle replacement, and has done so only for procedures done in England and Wales. In April 2012, however, we extended our data collection to include elbow and shoulder joint replacements, as well as implementing a two-year pilot study of Patient Reported Outcomes Measures for shoulders, with data collected from patients at six months post-surgery. As well as new joint types, we have also extended the NJR geographically with the inclusion of data from Northern Ireland, and are currently in discussions to incorporate data from the Isle of Man.
Given the growth and development of the NJR, we took the opportunity in this, our tenth year of operation, to step back and review our purpose and strategic aims, as well as considering how our
structure, funding model and major activities support our aims. Key developments from this review include the establishment of a new Executive Committee to handle the rapidly expanding day-to-day management of the NJR; establishment of a new Medical Advisory Committee intended to provide a forum to gather views from our medical stakeholders, in particular the medical societies; the creation of a new NJR Medical Director executive post to partially relieve the burden carried by volunteers on the Steering Committee; and, we have established a formal Patient Network to ensure that the voice of the patient is heard in all the work we do. In addition, we plan to broaden the membership of the NJR Sub-committees to include a wider representation of stakeholders than those exclusively on the NJR Steering Committee. Work is ongoing to finalise these arrangements.
In September 2012, we launched our new Annual Clinical Reports, which were circulated to Trust, Local Health Board and independent provider Chief Executives detailing a range of performance information for their hospitals. This was a major step forward in providing units with feedback on the data held for them by the NJR.
Another important initiative in which the NJR has been an integral member is the establishment of the initiative Beyond Compliance, which invites implant manufacturers on a voluntary basis to go beyond the requirements of the implant CE mark and enter a rigorous, ongoing monitoring process for newly-developed implants. The NJR supports the British Orthopaedic Association and the Medicines and Healthcare products Regulatory Agency, who are the joint leaders of this programme, by providing data and operational support. We are proud to be a part of this world-leading development.
In support of better cost-effectiveness of implant purchasing by Trusts, the NJR was commissioned by the Department of Health under the QIPP Orthopaedic
Chairman’s introductionLaurel Powers-Freeling
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Procurement Group (see page 45) to look at pricing data across NHS Trusts and Local Health Boards in England and Wales; 35 units have been involved in the pilot study to date. By matching actual cost data with NJR data, a potential suite of tools will enable healthcare organisations to analyse and compare spend and usage of orthopaedic implant products. The goal is to develop a model that can be extended nationally.
NHS England recently announced through the ‘Everyone Counts’ initiative that outcome of surgery at individual consultant level would be published by the end of June 2013 for ten clinical areas, one of which is hip and knee, and which is supported by data from the NJR. At the same time, the NJR has also developed a surgeon and hospital profile system that has been used as the publication vehicle. The magnitude and complexity of this exercise for orthopaedics has relied on a huge amount of work and collaboration between the NJR and the British Orthopaedic Association, with support from the specialist societies, the British Association for Surgery of the Knee and the British Hip Society. Despite very tight deadlines, we were able to publish data on the new NJR system, which we intend to develop further in the coming year to provide surgeons and trusts with the ability to customise profiles that are made available to the public.
In June this year, the NJR hosted the 2nd Annual Congress for the International Society of Arthroplasty Registries (ISAR) in Stratford-upon-Avon, providing us with an opportunity to showcase our work and influence the development of future international cooperation. We look forward to the 3rd ISAR Congress in Boston, USA in 2014.
As we move from this year to next, the NJR has a number of new activities and plans that we believe will further support our stakeholders, including:
•Patient Implant Cards – we are undertaking a pilot study with the aim of introducing a patient implant card designed to improve online access to information for patients and also provide feedback to the NJR.
•NJR Research Fellows – due to the success of the NJR Research Fellows posts, the programme will continue, with one new Fellow now appointed
and with intentions to make a further appointment this year.
•NJR Communications – we have developed a new communications strategy for 2013/14, which has included the recent launch of NJR social media platforms, including Twitter, Facebook and our first eBulletin news service, with more innovations planned for next year.
•New Annual Report format – work is ongoing that will see NJR Annual Reporting data presented online, taking into account a stakeholder survey of preferences and views.
Finally, we will be holding a special celebration of the NJR’s ‘10th Birthday’ this September with a special stakeholder reception to launch this Annual Report.
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While I gave my thanks to colleagues at the beginning of this introduction, I would like to close by mentioning the members of the NJRSC who will be stepping-down during 2013/14, which include Professor Paul Gregg, Mick Borroff and Professor Alex MacGregor – all of whom have been on the Steering Committee since its inception. I would also like to thank Andrew Woodhead who has served on the NJRSC since 2007, and Dean Sleigh who stepped down in March 2013 and has served on the NJRSC since 2008. Each of them can rightly take pride in having built the NJR and in the importance of the work we do today.
Yours sincerely,
Laurel Powers-Freeling
Chairman, National Joint Registry Steering Committee
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Foreword from the Chairman of the Editorial BoardThe 2013/14 year marks the 10th anniversary of the National Joint Registry. By 31 March 2013 the NJR held more than 1.4 million records and nearly 200,000 submissions were received on hip, knee, ankle, shoulder, and elbow replacements. The in-year compliance is over 90% and the overall compliance, since 2003, is 86.8%. It was interesting to note that 55% of joint replacement activity carried out in independent hospitals was funded by the NHS.
The previous trend in terms of the uncemented fixation continues and the use of metal-on-polyethylene and ceramic-on-ceramic bearings predominate. The use of the metal-on-metal articulation has declined to very low levels. The knee replacement trends continue very much as they have done over the lifespan of the registry with the posterior cruciate retaining bicondylar cemented knee being the procedure of choice. Despite higher observed revision probability with the unicondylar knees these have still maintained about 8% of the market.
An important change this year in Part Three of the report has been the use of the Kaplan-Meier survivorship estimates for all information in the tables instead of the Nelson-Aalen cumulative hazard used previously, although the latter technique has been used for the graphs. The details of this are explained in Part Three itself. It is also important to note that the data has not been fully risk adjusted. Instead it has been presented according to a combination of fixation attributes and in the larger groups also with different bearing attributes as we did last year. Instead of considering survival of a single component, both the stem and cup brand have been considered together and in the larger groups further broken down in relation to the bearing used within the brand companies. This allows a more realistic view on the effect of the ‘whole’ hip replacement. However, as the data has not been fully risk adjusted care needs to be taken interpreting the results and, as always, I would recommend looking at the upper and lower confidence intervals around the mean to ascertain whether any differences are likely to be statistically significant.
For the first time Patient Reported Outcome Measures are reported. This represents a major step forward looking at other factors apart from revision which may affect the outcome. It is still relatively early days both in terms of understanding how this data should be statistically analysed and how the findings should be incorporated. With such a large database the NJR is clearly having a larger influence on the evidence base. However, it will probably take another ten years before the full effects and benefits of bearing performance are fully appreciated.
The availability of new materials and a better understanding of the biomechanics of joints have resulted in many new innovations being available to orthopaedic surgeons. An important role of the NJR has been to maintain a close surveillance on the early adoption of new technologies and our implant performance Scrutiny Group regularly review clinical publications and results reported by international registries. It is important that this review of other data takes place because the numbers of any new product implanted in one country are often too small for any definitive decisions on performance to be made within the first couple of years following the initial implantations.
The planning for the 11th Annual Report is already underway and I would like to point out that the format of next year’s report is likely to be significantly different. We are intending to concentrate on providing online and interactive report features. The traditional printed report will be a much briefer summary and in this context the 10th Annual Report is likely to be last of the larger report formats.
Once again I would like to thank everybody who has contributed to the registry, not least to the patients for allowing their data to be recorded and to all surgeons for entering their data in to the NJR.
Martyn Porter
Chairman, Editorial Board
Executivesummary
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Part 1: Annual progress
The 10th Annual Report of the National Joint Registry for England, Wales and Northern Ireland is the formal public report for the period 1 April 2012 to 31 March 2013 (Part One). Also included are statistics on joint replacement activity for the period 1 January to 31 December 2012 (Part Two) and survivorship and more detailed statistical analysis on hip and knee joint replacement surgery using data from 1 April 2003 to 31 December 2012 (Part Three). Part Four shows indicators for hip and knee joint replacement procedures by Trust and unit based on the 2012 calendar year.
The NJR began collecting data on hip and knee replacement operations on 1 April 2003. Data collection on ankle replacements began on 1 April 2010 and on shoulder and elbow replacements on 1 April 2012. Data collection in Northern Ireland began in February 2013. The total number of procedures recorded in the NJR exceeded 1.4 million records by 31 March 2013, with 2012/13 having the highest ever annual number of submissions at 196,403.
The NJR uses rates of compliance (case ascertainment), patient consent, and linkability (the ability to link a patient’s primary procedure to a revision procedure) as its key data quality indicators. Details of how these are calculated are included in the report. At 91%, 2012/13 saw the highest annual rate of consent recorded, whilst linkability remained constant at 96%.
The NJR Steering Committee and its sub-committees are vital to the running and development of the NJR. A key focus of the steering committee throughout the last year has been to review the NJR’s priorities and its governance and operating model, in recognition of the great increase in scope and responsibilities of the NJR since its formation in November 2002.
The report highlights the ongoing work of the Implant Performance Sub-committee, the Surgeon Outlier Sub-committee, the NJR Research Sub-committee, the
NJR Editorial Board, and the NJR Data Quality Group. The reports from the respective Chairman of the Implant Performance Sub-committee and the Surgeon Outlier Sub-committee outline how outlier analysis is undertaken and include the high level outcomes of the monitoring process for 2012/13.
The work of the NJR has continued to expand throughout 2012/13. In April 2012, details of shoulder and elbow joint replacement procedures were added to the data collection, Northern Ireland joined the NJR in February 2013, and the NJR began the next phase of its PROMs study: the follow up, at three years, of approximately 43,000 hip and knee replacement patients. The report also outlines two other major developments being supported by the NJR: Price Benchmarking and Beyond Compliance. Price Benchmarking is sponsored by the Department of Health and is currently in the second phase of its pilot. The service, when fully implemented, will provide a comparison of implant prices across NHS England and NHS Wales. Beyond Compliance is a voluntary, post-market surveillance process that goes beyond the normal, regulatory requirements for the introduction, to market, of new implants. Using a central data repository consisting of data from numerous sources, new implants can be more closely followed up with the intention of them being introduced to market in a more controlled fashion than has been possible previously.
The NJR has continued to increase its presence internationally and is a full member of both the International Society of Arthroplasty Registers (ISAR) and the International Consortium of Orthopaedic Registers (ICOR). The NJR recently hosted ISAR’s 2nd Annual Congress (June 2013).
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Part Two of the NJR 10th Annual Report includes data on clinical activity – volumes and surgical technique, in relation to hip, knee and ankle procedures carried out in England and Wales between 1 January 2012 and 31 December 2012. It also includes information on elbow and shoulder prostheses between 1 April 2012 and 31 December 2012. To be included in the report all procedures must have been entered into the NJR by 28 February 2013.
During 2012 there were 413 orthopaedic units that were active and this included 240 NHS hospitals and 163 independent units. The remaining units were independent sector treatment centres. A total of 96% of units submitted at least one procedure carried out within the calendar year 2012 to the NJR. The average number of hip replacements submitted per unit was 218 and for knee replacement 235.
Just over 1% of activity in NHS hospitals is independently funded but in independent hospitals the majority of work (55%) is now funded by the NHS.
Hip replacement procedures
A total of 86,488 hip procedures were recorded on the NJR in 2012 which represented a 7.5% increase from last year. Of these 76,448 were primary and 10,040 were revision procedures. The ‘revision’ burden now stands at 12% of total hip activity compared to 11% in 2011. In terms of fixation of hip replacement in 2012 the trend was very similar to 2011 where cementless fixation predominates at 43% with a slight reduction in cemented hip replacement to 33% (compared to 36% last year) and a slight increase in the use of hybrid fixation at 20% (compared to 18% last year). The use of hip resurfacing has now fallen to 1% and large head metal-on-metal replacements to 2%. Patient characteristics have remained fairly constant with an average age of 68.7 years and a predominance of female patients (60%).
The proportion of patients within age ranges has remained virtually the same in the 10 years that the NJR has been recording data with about one third of patients being in the age range 70 to 79 and just over 1% being less than 40 years at the time of surgery. The average body mass index (BMI) increased very slightly to 28.7 compared to 28.6 in 2011.
The ASA distribution is identical to last year with only 15% being ASA grade 1 and the majority of patients being ASA grade 2. However, there were important differences in patients ASA grades between those treated within NHS hospitals compared to independent hospitals. For example, 21% of patients treated in NHS hospitals had an ASA grade 3 compared to just 7% in independent hospitals and patients with ASA grade 1 (fittest patients) were just 11% in the NHS and almost double (21%) in independent hospitals. These data would suggest that a much fitter cohort of patients are treated in independent hospitals which is important when comparing outcomes between these two sectors.
As previously noted, both the age and gender of the patient have strong associations with the type of replacement carried out. For example, in female patients less than 50 years of age about 68% were cementless replacements compared to just 21% in the age range between 80 and 89.
The most common diagnosis was osteoarthritis but again the age of the patient had a strong influence on the diagnosis and in young patients, as expected, there was a much higher incidence of patients with a diagnosis of avascular necrosis and hip dysplasia compared to the more elderly cohort of patients.
The surgical techniques were very similar to those recorded in 2011, the lateral position being used in 93% of cases and a slight increase in the use of the posterior approach to 61% compared to 59% last year.
Part 2: Clinical activity 2012
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Minimally-invasive surgery (MIS) was recorded as being used in 5% and image-guided surgery was used very infrequently in just 0.3% of cases.
In terms of thromboprophylaxis a multi-modal regime was commonly used with low molecular weight Heparin being used in 73% of cases and TED stockings in 66%.
In 2012, 146 brands of femoral stem, 101 brands of acetabular cup and eight brands of resurfacing cup were used. Using the Orthopaedic Data Evaluation Panel (ODEP) ratings only about half of all femoral and acetabular components had an ODEP rating in primary arthroplasty. However, the components used with the full 10A benchmark rating was 88% for cemented stems, 69% for cementless stems, 34% in cemented cups, 3% for cementless cups and 63% for resurfacing cups.
In terms of brand choice the Exeter V40 stem was most commonly used in 66% of cemented hips and the contemporary cup used in about 34% of cases. A rapid rise of the Exeter rim fit cup introduced in 2010 was observed. This now has a market share of about 12%, obtained in a very short time period.
In regard to cementless fixation the Corail stem has maintained its position as the most commonly used stem in about 46% of cases and the Pinnacle socket in 33%. The use of resurfacing in 2012 fell to 1,075 compared to 1,883 in 2011. The Birmingham hip resurfacing is the most popular implant used.
The preference to use large diameter heads to improve stability continues with about 30% of femoral heads being 36 millimetres, another 30% being 32 millimetres and nearly 40% being 28 millimetres. Head sizes over 36 millimetres are now only rarely used as is the smaller head size of 22.25 millimetres.
In terms of bearing combinations the use of metal-on-polyethylene (this includes standard and cross link polyethylene) remains the most common selection in just under 60% of cases followed by a ceramic-on-ceramic articulation. There is a slight increase in the use of ceramic-on-polyethylene and the use of metal-on-metal articulation continues to fall.
There were 10,040 hip revision procedures recorded in 2012 of which 88% were single-stage revisions. Aseptic loosening was the most commonly recorded indication for revision surgery in 40%, infection in 12% that increased to 13% for adverse soft tissue reactions (1,330 cases). Patients undergoing revision surgery are less fit than patients undergoing primary replacement with one third of patients being graded as ASA grade 3 for staged revision surgery. NHS hospitals incurred most of the burden of revision operations – 83% compared to independent hospitals 15%. This differs to the activity of primary surgery where NHS hospitals carried out 69% of primary surgery compared to 27% in the independent sector. When the revision is carried out in a single operation both the cup and stem are removed in 45% of cases, the acetabular component only in 30% and the femoral stem only in 14%. The revision components used during single-stage hip revision is approximately equal between cemented and cementless (28% versus 29%) whereas on the acetabular side cementless components are used three times more frequently (58% versus 18%) than cemented components.
Knee replacement procedures
In 2012, 90,842 knee replacement procedures were entered into the NJR representing an increase of 7.3% compared to 2011. In these procedures 84,833 were primaries and 6,009 were revision procedures. The revision burden of knee replacement is just over 6.5% which is just over half of the revision burden of hip replacements. The type of knee replacements used has remained remarkably constant over the last three to four years with 86% being cemented total knee replacements, 8% being unicondylar replacements, 3% total knee replacements not using cement and only about 1% being patello-femoral replacements.
In terms of surgical technique a medial parapatellar approach was used in 93% of procedures. MIS was used in just 2% of total knee replacements but much more frequently in unicondylar replacements (46%). The patella was resurfaced in 38% of primary cemented knee replacements but in just 7% of cementless total knee replacements. As in hip replacements thromboprophylaxis tended to be multi-modal with low molecular weight Heparin being used in 72% of cases and TED stockings in 70%. The PFC
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Sigma was the most commonly used total condylar knee replacement being used in just under 37% of cases. For the unicondylar replacement there was a slight decrease in the use of the Oxford which had just over 60% of the market share.
A total of 6,009 knee revision procedures were reported in 2012 representing an increase of 17% compared to 2011. The vast majority of these (78%) were single-stage revision operations. As in hip revisions, patients undergoing revision knee replacements tended to be less fit than patients undergoing primary replacement and 85% of the revisions were carried out within NHS hospitals compared to 69% of primaries indicating that it is the NHS that picks up a disproportionate amount of the knee revision burden. Indications for revision surgery were recorded as aseptic loosening in 32% of cases and infection in 22%.
Ankle replacement procedures
This is only the second full year of recording ankle replacements with data collection starting on 1 April 2010. The compliance has improved from 64% last year to 77%.
Of the ankle replacements recorded for the calendar year 2012 there were 590 ankle replacements including 540 primaries and 50 revisions. The majority, 86%, were funded by the NHS and the patient characteristics in terms of ASA and BMI were not dissimilar to that of patients undergoing hip and knee replacement. Unlike hip replacements male gender was recorded in 58% of cases and osteoarthritis was the most common diagnosis in 84% and inflammatory arthritis in 13%. Additional information is recorded on ankles including tibia-hindfoot alignment of 46% being in neutral position and the range of ankle dorsiflexion, 42% having dorsiflexion between five and 20 degrees and 54% having plantarflexion between five and 15 degrees.
In terms of surgical technique the anterior approach was the most common in 97% and in 11% Achilles tendon lengthening was carried out. Bone grafts were used in 15%.
For prophylaxis low molecular weight Heparin was used in 80%. 56% had TED stockings but there was
less reliance on calf or foot compression compared to hip and knee replacements.
The main implant used was the DePuy Mobility in 52% followed by the Zenith ankle replacement manufactured by Corin in 20%.
Of the 50 ankle revision procedures most, 46, were carried out on the NHS. The main indicators for revision were undiagnosed pain (36%), suspicion of infection (26%), aseptic loosening of the tibial component (18%) and aseptic loosening of the talar component (16%).
Elbow replacement procedures
This is the first year that we have reported on elbow replacement and shoulder replacement surgery with data collection starting on 1 April 2012 and therefore the reporting period is nine months rather than the full calendar year.
There were 288 elbow replacement procedures which include 214 primary and 74 revision procedures. Many of the revision procedures clearly relate to previous periods of implantation. 89% of the primaries were total replacements and 9% were radial head replacements. The indications for surgery were more variable compared to other procedures in this report with osteoarthritis only comprising 32%, inflammatory arthritis 33% and trauma or trauma sequelae comprising a further 37%. The average age of patients was 65 (female) and 67 (male). 89% were treated in the NHS.
The posterior approach was used in 89% of cases and humeral bone graft in 16%. 59% had low molecular weight Heparin and 54% TED stockings.
Of the 74 revision procedures, 50% were carried out for aseptic loosening, 18% for infection, 12% for instability and 19% for peri-prosthetic fracture. The Coonrad Morrey prosthesis manufactured by Zimmer had 45% of the market share.
Shoulder replacement procedures
Shoulder replacements are again reported for nine months of the calendar year 2012 for reasons explained under the elbow section.
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A total of 2,225 shoulder replacement procedures were recorded including 1,968 primaries and 257 revisions. Of the primary procedures there was quite a diverse mix of prostheses with 27% being primary total replacements, 15% hemi-arthroplasty, 6% resurfacing, 22% hemi-resurfacing and 30%, or 597, reverse prostheses. Osteoarthritis was the primary diagnosis in 61% of cases but 24% of patients were reported to have cuff tear arthropathy. The mean age of female patients (73.2 years) was greater than that of male patients (68.8 years) and 72% of patients were female.
The most common surgical approach was the Delta pectoral approach in 75%. Humeral bone graft was used in 12%. A tenotomy of the long head of biceps was carried out in 45% of patients and the rotator cuff condition was described as normal in just 43%. 57% of patients received low molecular weight Heparin.
Of the 257 revision procedures, the indications for surgery were variable; just 14% for aseptic loosening, 30% were conversion of hemi to total and 25% were revision for cuff insufficiency.
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Part Three of the 10th Annual Report describes the clinical outcomes represented by survivorship data and mortality in relation to hip and knee replacements carried out in England and Wales between 1 April 2003 and 31 December 2012. This represents nearly ten years of survivorship information.
It also includes for the first time pre- and post-operative Patient Reported Outcome Measures (PROMs) collected since April 2009.
The National Joint Registry contains over 1.4 million operations but because of exclusions in relation to patient identifiers, linkage issues and other causes, the survivorship analysis was based on 539,372 primary hips with 11,780 linked first revisions, 589,028 primary knees and 11,666 linked first revisions and 1,417 ankles with 9 linked first revisions.
This year we have used Kaplan-Meier estimates and the cumulative chance of revision of first implant or death of patient but we have continued to use Nelson-Aalen cumulative hazard estimates for the graphs. Details of these statistical methodologies are explained in the appendices to this report.
Hip replacement procedures
The data describes the number of patients and percentages of implant fixation combinations with those of bearing surface combinations and illustrates the change of usage of both fixation and bearing between 2003 and 2012 inclusive. This shows interesting changes over the years, for example in 2003, 55.3% of all hip replacements were metal-on-polyethylene cemented replacements but in 2012 this has nearly halved to just 28.6%. In comparison the metal-on-polyethylene uncemented hip replacement was used in just 6.2% of cases in 2003 and this has almost trebled to 17.8% in 2012. The ceramic-on-ceramic uncemented hip replacement has also shown a rapid increase from just 3.5% in 2003 to a nearly six fold increase to 19.2% in 2012. The use of metal-on-
metal resurfacing peaked at 10.8% in 2006 and was just 1.3% in 2012.
The unadjusted Kaplan-Meier survivorship estimates are presented for each of these fixation and bearing combinations within the report. The lowest revision rate at nine years was that of the ceramic-on-polyethylene cemented hip replacement with a cumulative probability of first revision of just 1.84% (95% CI of 1.51% to 2.24%). Considering all bearing combinations overall, cemented hip replacement had a cumulative percentage revision probability of 2.71% (2.57% to 2.87%) at nine years after operation compared to 6.71% (6.40% to 7.05%) with uncemented fixation, once again the ceramic-on-polyethylene bearing had the lowest revision rate within the uncemented fixation group. The hybrid and reversed hybrid groups were somewhere between the cemented and uncemented fixation groups with a nine-year revision probability of 3.42% (3.10% to 3.76%) for hybrids and 3.37% (2.52% to 4.33%) for reverse hybrids.
When a metal-on-metal articulation was used with cementless fixation the nine-year revision probability of a first implant was 17.66% (15.93% to 19.56%). This was similar to the metal-on-metal resurfacing which had a revision probability of 12.31% (11.62% to 13.04%) at nine years.
The number of revisions by indication for revision are presented per 1,000 patient-years for fixation and bearing, for example for dislocation/subluxation there were 0.89 (0.83-0.96) revisions per 1,000 patient-years with cemented fixation but this was just 0.43 (0.34 to 0.53) when metal-on-metal resurfacing was used. Soft tissue reaction was recorded in 0.02 (0.01 to 0.05) of cemented metal-on-polyethylene replacements compared to 3.55 (3.05 to 4.13) of metal-on-metal resurfacing and 5.50 (4.90 to 6.20) of metal-on-metal uncemented replacement. The revision rates following surgery were not linear, for example the revision rate for 1,000 patient-years within one
Part 3: Outcomes after joint replacement 2003 to 2012
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year of surgery was 7.71 (7.47 to 7.96) but this fell to 4.60 (4.45 to 4.75) between one and three years from primary operation.
The Kaplan-Meier cumulative probabilities of a first prosthesis revision are listed for a large number of cup stem brand combinations. For example, the cemented Exeter V40 – Elite Plus Ogee socket combination had a revision probability after nine years of 1.57% (1.30% to 1.90%) and the uncemented Furlong HAC stem – CSF had a cumulative probability of first revision nine years after surgery of 2.97% (2.59% to 3.40%).
For the cup stem brand combinations with over 10,000 cases the brand combinations were further broken down to examine the effect of bearing surface, for example, the Exeter V40 Contemporary metal-on-polyethylene bearing had a nine-year first revision probability of 2.33% (2.00% to 2.70%) but when the ceramic-on-polyethylene bearing was used with the same brands the cumulative chance of revision after nine years was 1.87% (1.20% to 2.90%). The Corail Pinnacle group was interesting as the effect of the bearing could be clearly seen. Eight years post surgery, the chance of first revision was 5.89% (5.11% to 6.79%). However, within this group with a Corail Pinnacle combination, if a ceramic-on-polyethylene bearing was used the probability of first revision was just 1.84% (1.34% to 2.51%) whereas when a metal-on-metal bearing was used the cumulative probability was 11.10% (9.06% to 13.58%).
With resurfacing clear differences could be seen between the brands. Eight years after the primary surgery, the probability of first revision with the Birmingham hip (BHR) resurfacing was 6.61% (6.12% to 7.13%) compared to 29.69% (27.03% to 32.55%) when the ASR was used.
Cumulative revision probabilities were also considered as a function of head size and head material when used with a polyethylene liner. This allowed multiple comparisons, for example, when a metal head was used with a polyethylene liner contained in a metal shell, the revision probabilities were higher for the larger 44 millimetre head compared to the 28 millimetre head.
The cumulative probability of death at different times after the primary surgery is presented broken down by gender and age group. The risk of death within 90 days of surgery overall was 0.51% (0.50% to 0.53%). In female patients this ranged from 0.21% (0.16% to 0.27%) in patients less than 55 years to 1.31% (1.22% to 1.41%) in patients 80 years and above and at nine years after primary surgery the cumulative probability of death in male patients less than 55 years was 4.39% (3.88% to 4.96%) compared to 65.67% (63.62% to 67.72%) for patients aged 80 and above.
One of the in-depth studies, that of metal-on-metal hip resurfacing was published in The Lancet in October 2012. In this paper the effects of age, gender and femoral head size are considered and the best outcomes were observed in male patients aged 55 years with a head size of 54 millimetres where the revision rate at seven years was 2.47% (1.90% to 3.20%).
Knee replacement procedures
In comparison to hip replacements, the changes in fixation, constraint and type of knee replacement has not varied as much over the observation period 2003 to 2012. The use of cemented total replacements increased from 81.5% in 2003 to 86.9% in 2012 and within cemented groups the unconstrained (posterior-cruciate retaining) fixed knee increased from 53.3% in 2003 to 59.8% in 2012. Despite some concerns with higher revision rates seen amongst unicondylar replacements, the use of these remains fairly static between 8% and 9% and similarly for patello-femoral replacements (which are relatively low volume), the use of these ranged from just 1.0% in 2003 to 1.3 % in 2012.
It was reassuring that the most commonly used replacement, the all cemented total replacement unconstrained and fixed, had a low cumulative probability of first revision of just 2.90% (95% CI of 2.77% to 3.04%) at nine years. The cemented mobile constrained condylar knees had a revision probability of 4.48% (2.87% to 6.96%) at nine years. With uncemented and hybrid replacements the posterior-stabilised knees had a revision probability of 6.70% (5.15% to 8.70%) at nine years. As previously noted
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unicondylar knees had a high revision probability of 11.57% (10.92% to 12.26%) at nine years and the patello-femoral replacement had a revision probability of 16.11% (14.09% to 18.39%) at the same time period.
The stated reasons for revision by fixation are described as revision rates per 1,000 patient-years. The revision rate was 1.10 (1.06 to 1.15) revisions for infection and for component size mismatch 0.73 (0.70 to 0.77). There was a further breakdown of reasons for revision by fixation and degree of constraint.
The revision probabilities are described up to nine years following surgery for the main brands; compared to hip replacement there was less variation in revision probability. For example, the PFC Sigma bicondylar knee had a cumulative revision probability of 2.45% (2.30% to 2.61%) at nine years and the Genesis 2 2.43% (2.11% to 2.79%). Some knees performed less well including the Kinemax with a revision probability of 4.30% (3.81% to 4.86%) at nine years and the Rotaglide Plus which had a revision probability of 5.45% (4.19% to 7.07%). When patello-femoral joints were considered the seven-year revision probability of the Avon knee was 10.94% (9.49% to 12.60%) but for the Journey PFJ Oxinium it was 17.52% (12.98% to 23.41%). There was also variation with unicondylar knees, for example the Zimmer unicompartmental knee had a revision probability of 5.27% (4.15% to 6.69%) at nine years compared to the Preservation which had a revision probability of 17.31% (14.43% to 20.68%).
When considering the type of constraint within the brand class there was generally low variation but there were some differences, for example within the Nexgen brand the cumulative revision probability with a cemented unconstrained fixed tibial insert was 2.44% (2.03% to 2.93%) at nine years compared to 3.62% (3.20% to 4.41%) when the Nexgen posterior-stabilised fixed insert was used.
The cumulative probability of patient death at different times after knee replacement had a similar pattern to that of hip replacement. For all cases the 90-day mortality probability was 0.36% (0.34% to 0.39%). At nine years this increased to 22.27% (21.95% to 22.59%). In female patients less than 55 years the
probability of death was 3.55% (2.88% to 4.37%) at nine years compared to 51.00% (49.55% to 52.46%) in patients 80 years or older.
Ankle replacement procedures
Because of the more recent inclusion of ankles and relatively small numbers, limited data are presented on ankle replacements. There were 1,417 primary operations in a population with a median age of 67 years, 57.2% of patients were male. Nearly all the ankle replacements were cementless. The Mobility brand was used in 56.5% of cases. There were only nine revisions recorded. Mortality was relatively low following ankle surgery with a 90-day cumulative mortality of 0.14% (0.04% to 0.58%) and a two-year cumulative probability of 1.40% (0.69% to 2.83%).
Patient Reported Outcome Measures (PROMs)
For the first time the NJR reports on PROMs. PROMs data, which is part of an NHS-funded initiative, is collected separately from the NJR. This collection has only been in action since April 2009 and relates to a pre-operative questionnaire and a follow-up questionnaire about six months following surgery. Data includes EQ-5D Index, EQ-5D Health Scale and Oxford Hip/Knee scores.
The original PROMs data file had 445,134 entries but for a variety of reasons a substantial proportion of these entries could not be matched to NJR data because of data quality issues, duplication and incomplete data.
Of the 124,136 PROMs entries linked to primary hip operations in the NJR, 99.7% of questionnaires were completed pre-operatively but only 75.6% post-operatively. For hip replacement surgery 85.6% of patients described themselves as being much better compared to before the operation, 10% reported having had a wound problem, 5.8% bleeding since the operation, 7.3% recorded they had been re-admitted to hospital since the operation and 2.1% declared they had had further surgery following the original operation.
In relation to change in EQ-5D, the median change following surgery was 0.380 (IQR 0.175 to 0.694) and for the patients treated with a cemented metal-
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on-polyethylene hip replacement the median change was 0.413 (0.159 to 0.694) and this compared to metal-on-metal resurfacing where the median change was 0.309 (0.165 to 0.484). However, the median pre-operative score for resurfacing was higher (0.587) for metal-on-metal compared to metal-on-polyethylene cemented (0.293).
The overall median change in EQ-5D Health Scale score (VAS) was 9 (IQR -2 to 20). This tended to be lower for all cemented where the median was 6 (-5 to 20) compared to uncemented where the median was 10 (-1 to 22).
The median change in Oxford hip score was 21 (IQR 14 to 28) for all cases and the variation between fixation types of bearings was very low.
For knee replacement surgery 70.8% of patients described themselves as being much better compared to how they were before the operation, 13.4% described having had a wound problem, 7.9% bleeding, 9.6% having been re-admitted and 3.3% having further surgery.
The median change in EQ-5D Index for all knee primaries (with scores at both time points) was 0.275 (IQR 0.069 to 0.568). The median change was lower for patello-femoral replacement (0.105). The median change in EQ-5D Healthscale score (VAS) was 3 (-7 to 15) for all cases but 0 for patello-femoral replacement (-10 to 15). The median change in Oxford knee score for all cases was 16 (9 to 22) but again was lower for patello-femoral joints at 10 (4 to 18).
1.1 Introduction
Annual progressPart 1
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1.1.1 The National Joint Registry
The National Joint Registry for England, Wales and Northern Ireland has collected hip and knee joint replacement data since 2003. The NJR has recorded data on ankle replacement surgery since April 2010 and from April 2012, data on shoulder and elbow joint replacement surgery. Northern Ireland has been submitting data since February 2013. The NJR is currently the largest register of its kind in the world, with over 1.4 million recorded procedures.
The NJR’s purpose and aims are set out in its strategic plan and are summarised below:
Mission statement:‘The purpose of the National Joint Registry for England, Wales and Northern Ireland is to collect high quality and relevant data about joint replacement surgery in order to provide an early warning of issues relating to patient safety.
In a continuous drive to improve the quality of outcomes and ensure the quality and cost effectiveness of joint replacement surgery, the NJR will monitor and report on outcomes, and support and enable related research.’
Strategic goals:
1. Monitor in real time the outcomes achieved by brand of prosthesis, hospital and surgeon, and highlight where these fall below an expected performance in order to allow prompt investigation and to support follow-up action
2. Inform patients, clinicians, providers and commissioners of healthcare, regulators and implant suppliers of the outcomes achieved in joint replacement surgery
3. Evidence variations in outcome achieved across surgical practice in order to inform best practice
4. Enhance patient awareness of joint replacement outcomes to better inform patient choice and patients’ quality of experience through engagement with patients and patient organisations
5. Support evidence-based purchasing of joint replacement implants for healthcare providers to support quality and cost effectiveness
6. Support suppliers in the routine post-market surveillance of implants and provide information to clinicians, patients, hospital management and the regulatory authorities
In July 2012, the NJR Steering Committee, along with invited stakeholders, held a one-day workshop to define the key activities necessary to support those aims and their relative priorities.
1.1.2 Management and funding
The NJR is managed by the Healthcare Quality Improvement Partnership (HQIP) under a contract with NHS England as part of the delivery of the National Clinical Audit and Patient Outcomes Programme (NCAPOP). HQIP support the work of the NJR Steering Committee and all its sub-committees. The NJR Steering Committee, which met four times in 2012/13, is responsible for overseeing the strategic direction and running of the NJR. Last year its status changed from that of an advisory non-departmental public body (ANDPB) to Departmental Expert Committee. Its members are currently appointed by the Department of Health (DH) Appointments Team following a formal recruitment process and the current list of members and their declarations are listed in Appendix 1. The Steering Committee has a lay Chairman, Ms Laurel Powers-Freeling.
There are currently six sub-committees which support the work of the NJR Steering Committee:
•The Editorial Board Chairman, Mr Martyn Porter
•The Implant Performance Sub-committee Chairman, Mr Keith Tucker
•The Surgeon Outliers Sub-committee Chairman, Professor Paul Gregg
•The Research Sub-committee Chairman, Professor Alex Macgregor
•The Regional Clinical Coordinators’ (RCC) Network Chairman, Mr Peter Howard
•The Data Quality Group Chairman, Professor Paul Gregg
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In early 2013, to reflect its change in status, the Steering Committee started a review of the NJR’s governance and committee structure and composition. The outcomes of the review are included in Section 1.3.2 below.
The NJR services are delivered under three separate contracts:
•The NJR Centre, managed and staffed by Northgate Information Solutions (UK) Ltd. Northgate is responsible for the management and development of the NJR’s IT infrastructure, software applications, data management and reporting services. This work is complemented by the NJR Service Desk, a team who provide day-to-day information and support to stakeholders, and the NJR Regional Coordinators (RC), an eight-strong team providing on-site support to orthopaedic units in hospitals.
•The NJR statistical support, analysis and research team, based at the University of Bristol. The team is responsible for the delivery of statistical analyses of NJR data and data from other sources, and for developing the statistical methodologies for the identification of potential outlier performance.
Their role also includes ad hoc data analyses, in addition to those included in the NJR Annual Report, that are central to the work of the Implant Performance Group and the Surgeon Outliers Sub-committee.
•NJR Communications, managed by HQIP. This is a programme of stakeholder and multi-media communication to support the delivery of the strategic plan including the publication of the Public and Patient Guide to the NJR Annual Report. The HQIP communications team also support the Editorial Board and Regional Clinical Coordinators’ Network.
Currently the NJR is funded through a levy raised on the sale of hip, knee, ankle, elbow, and shoulder implants. HQIP manages the levy payment collection and holds the NJR budget on behalf of the Steering Committee. The funding model is being reviewed and is likely to change in financial year 2013/14.
1.1.3 Content of the 10th Annual Report
The format of this report is similar to the 9th Annual Report:
•Part One is a general outline of the work of the NJR for the financial year 1 April 2012 to 31 March 2013. In addition to summary statistics relating to the NJR’s key data quality indicators, this section includes a summary of the major activities undertaken by the NJR and individual reports on the work of the sub-committees.
•Part Two is a description of joint replacement activity reported to the NJR as having been carried out in the calendar year 1 January to 31 December 2012.
•Part Three provides an analysis of survivorship of hip, knee and ankle replacement procedures carried out between 1 April 2003 and 31 December 2012. Data from the Hospital Episodes Statistics (HES) service, Patient Episode Database for Wales (PEDW), and the English Patient Reported Outcomes Measures (PROMs) programme are also included in the analysis.
•Part Four provides a series of reports about clinical activity and outcomes at both Trust and unit level.
Part 11.2 Data completeness and quality
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1.2.1 Key indicators
Whilst NHS hospitals in England and Wales have always been ‘expected’ to submit data to the NJR, it has always been mandatory for independent sector units in England and Wales since the registry started. However, the Standard NHS Contract for Acute Services was amended in April 2011 (Section 12.1.2) and now states that all providers shall participate in audits relevant to the service they provide within NCAPOP, of which the NJR is part. The submission of complete data to the NJR is, therefore, now mandatory for all NHS Trusts and Foundation Trusts within England. The Welsh Government has agreed that the NJR is mandatory for all NHS Wales hospitals and the Northern Ireland Health and Social Care Board has written NJR data entry into NHS Trust contracts, this includes all NHS-funded procedures.
Performance against the three indicators of data quality (compliance, consent, and linkability) has continued to improve year on year, although the provision of continual support to orthopaedic units is required to maintain and improve performance levels. These figures are available throughout the year from NJR StatsOnline on the NJR website.
Compliance
The compliance rate is the proportion of procedure records submitted to the NJR compared with the levy returns for the number of implants sold.1 It is impossible to establish a one to one link between a single levy and the use of the implant and this comparison is subject to a number of factors, such as variation in the procurement cycle throughout the year. It is often the case that more procedures are reported than levies are collected, leading to a positive (>100%) compliance rate, followed by periods where there are more levies raised than procedures reported. For individual NHS Trusts, compliance can also be measured against data held in the Hospital Episodes Statistics (HES) service and the Patient Episode Database for Wales (PEDW) service, though there are
likely to be minor variations between the two because of coding differences. This comparison does not include privately funded procedures that take place in the independent sector in England and Wales as this data is not submitted to either HES or PEDW. The overall compliance rate from 1 April 2003 to 31 March 2013 was 86.8%.
Consent
The consent rate compares the number of records submitted where the patient has agreed to their personal data being stored on the NJR database with the number of procedures recorded on the NJR.2 It is a requirement in England, Wales, and Northern Ireland that patients ‘opt in’ to have their personal data held by the NJR. Patient details are essential for linking patient procedures in order to monitor joint replacement procedure outcomes and it follows that, without high rates of patient consent, the NJR will not achieve its goals. Patients are known to rarely decline consent, and a number of units regularly achieve 100% consent rates. Failures to record positive consent are usually due to the lack of robust processes in hospitals which ensure that the completed consent form is available to the person entering the procedure details. The consent rate for 2012/13 was 91.0%.
1 For compliance analysis only, the number of procedures excludes the following procedures: re-operations other than revision; stage 1 of a 2-stage revision; excision arthroplasty; amputation; and conversion to arthrodesis. These are excluded because they do not include the implantation of a component attracting the levy.
2 Personal information includes NHS number, surname, date of birth and postcode.
Why are there sometimes more procedures reported than levies collected, leading to compliance rates greater than 100%?
•Bulk buying of implants in one year or at different times in the year
•Not all levies collected by the implant suppliers
•Not all revision procedures use a leviable component
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Figure 1.1 Compliance, Consent, and Linkability Rates from 2003 to 2013.
Source: Procedures entered into the NJR 1 April 2003 to 31 March 2013 and levy submissions to NJR by implant suppliers.
2004/052003/04 2005/06 2006/07 2007/08 2008/09 2009/10
68.3
64.3
59.6
43.4
63.3
57.2
Compliance
Consent
Linkability
81.6
74.0
69.6
80.6
81.2
78.0
95.3
84.4
91.8
91.6
87.6
94.7
114.3
87.9
95.3
2010/11
106.8
89.0
95.8
2011/12 2012/13
90.3
90.5
96.0
91.0
91.0
95.6
Financial year
%
0
120
100
80
60
40
20
Compliance Consent Linkability
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Linkability
The linkability rate compares the number of records submitted with the patient’s NHS number with the number of procedures recorded on the NJR. The NHS number is required to link all primary and revision procedures relating to a single patient.3
The ability to link all operations relating to a single patient is vital in determining clinical outcomes. Operations are linked using the patient’s NHS number.
Low rates of linkability adversely affect the ability of the NJR to monitor clinical and implant performance.
Where the NHS number is missing, tracing is attempted using the NHS Demographics Batch Service. This relies on the patient’s name, date of birth and postcode being correctly entered. The linkability rate for 2012/13 was 95.6%.
3 NJR data is submitted for NHS number tracing and the ‘linkability’ figure includes NHS numbers that were traced subsequent to the operation details being submitted to the NJR.
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1.2.2 Operation totals
By 31 March 2013, 1,456,756 hip, knee, ankle, elbow, and shoulder replacement procedures had been reported to the NJR. There were 196,403 procedures submitted in 2012/13.
Table 1.1 shows the total number of hip and knee procedures recorded on the NJR in England and
Wales each year from 2008/09 to 2012/13. As for the previous five years, the number of knee replacement procedures (98,288) exceeded the number of hip replacement procedures (94,044) in 2012/13 (51% and 49% as a proportion). Table 1.1 also records ankle procedures from April 2010 and elbow and shoulder procedures from April 2012. Northern Ireland’s joint replacement data is included from February 2013.
Source: Procedures entered into the NJR 1 April 2008 to 31 March 2013.©
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Table 1.1 Total joint replacement procedures entered into the NJR, 2008/09 to 2012/13, recorded by country in which the procedure took place.
2008/09 2009/10 2010/11 2011/12 2012/13England hip 71,845 74,676 82,077 83,787 88,830
England knee 75,971 79,173 86,581 87,378 92,698
England shoulder 2,881
England elbow 345
England ankle 423 518 679
Wales hip 4,900 3,919 4,004 4,533 5,144
Wales knee 5,651 4,611 4,506 5,099 5,557
Wales shoulder 110
Wales elbow 13
Wales ankle 25 40 36
Northern Ireland hip 70
Northern Ireland knee 33
Northern Ireland shoulder 5
Northern Ireland elbow 0
Northern Ireland ankle 2
Total procedures 158,367 162,379 177,616 181,355 196,403
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Operation types
Table 1.2 below shows the number of procedures reported by type from 1 April 2008 to 31 March 2013. Primary operations make up 91.5% of all procedures
reported, whilst the proportion of revisions (less shoulders and elbows) has increased by 0.6% to 9.3% from 8.7% in 2011/12.
Source: Procedures entered into the NJR 1 April 2008 to 31 March 2013.
4 Re-operation information was not collected on the first version of the Minimum Dataset (MDSv1) from 1 April 2003 to 31 March 2004. It was included on MDSv2 from 1 April 2004 and removed from MDSv3 which came into use on 1 December 2007. However, some units are continuing to use MDSv2 which is why some re-operations continue to be reported. The figures are included for completeness only.
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Table 1.2 Total joint replacement procedures entered into the NJR, 2008/09 to 2012/13, recorded by procedure type.
2008/09 2009/10 2010/11 2011/12 2012/13Hip primary 69,342 70,268 76,927 78,405 82,837
Hip revision 7,327 8,245 9,117 9,914 11,207
Hip re-operation4 76 82 37 1 0
Knee primary 77,020 78,561 85,272 86,637 91,682
Knee revision 4,514 5,147 5,766 5,840 6,606
Knee re-operation4 88 76 49 0 0
Ankle primary 418 538 650
Ankle revision 30 20 67
Shoulder primary 2,666
Shoulder revision 330
Elbow primary 267
Elbow revision 91
158,367 162,379 177,616 181,355 196,403
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Procedures by provider type
There are four types of organisations in England carrying out hip, knee, ankle, elbow, and shoulder joint replacement surgery:
•NHS hospitals
•NHS treatment centres
•Independent sector hospitals
•Independent sector treatment centres (ISTCs)
There are no NHS treatment centres or ISTCs in either Wales or Northern Ireland and as the numbers for Northern Ireland only cover a six week period, they are grouped together as a provider.
Table 1.3 shows the proportion of procedures by type of provider.
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Table 1.3 Proportion of reported procedures by type of provider, 2008/09 to 2012/13.
2008/09 2009/10 2010/11 2011/12 2012/13Hips
NHS hospitals69.4% 71.6% 71.7% 70.8% 71.2%
53,231 56,272 61,707 62,570 66,952
Independent hospitals26.1% 24.4% 24.3% 25.2% 25.5%
20,040 19,164 20,881 22,256 23,947
ISTCs4.5% 4.0% 4.1% 4.0% 3.3%
3,474 3,159 3,493 3,494 3,075
Northern Ireland- - - - 0.1%
- - - - 70
All NJR 76,745 78,595 86,081 88,320 94,044
Knees
NHS hospitals70.2% 72.5% 72.2% 70.6% 70.7%
57,270 60,707 65,781 65,330 69,501
Independent hospitals24.2% 22.5% 23.1% 24.8% 25.6%
19,773 18,859 21,044 22,898 25,135
ISTCs5.6% 5.0% 4.7% 4.6% 3.7%
4,579 4,218 4,262 4,249 3,619
Northern Ireland- - - - <1%
- - - - 33
All NJR 81,622 83,784 91,087 92,477 98,288
Ankles
NHS hospitals- - 79.0% 76.0% 78.2%
- - 354 424 561
Independent hospitals- - 17.6% 19.4% 18.3%
- - 79 108 131
ISTCs- - 3.3% 4.7% 3.2%
- - 15 26 23
Northern Ireland- - - - 0.3%
- - - - 2
All NJR - - 448 558 717
Continued >
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Source: Procedures entered into the NJR 1 April 2008 to 31 March 2013.
Further information is available on the NJR website under ‘NJR 10th Annual Report’.
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2008/09 2009/10 2010/11 2011/12 2012/13Shoulders
NHS hospitals- - - - 82.6%
- - - - 2,476
Independent hospitals- - - - 14.7%
- - - - 439
ISTCs- - - - 2.5%
- - - - 76
Northern Ireland- - - - 0.2%
- - - - 5
All NJR - - - - 2,996
Elbows
NHS hospitals- - - - 94.1%
- - - - 337
Independent hospitals- - - - 5.6%
- - - - 20
ISTCs- - - - 0.3%
- - - - 1
Northern Ireland- - - - 0.0%
- - - - 0
All NJR - - - - 358
Table 1.3 (continued)
Part 11.3 Work of the NJR Steering Committee and its Sub-committees
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1.3.1 Introduction
This section highlights the work undertaken by the NJR Steering Committee and its sub-committees throughout 2012/13. The reports not only reflect the continually increasing requirements placed on the NJR by its numerous stakeholders but the commitment and efforts of the NJR Steering Committee members who receive no remuneration, other than travel and accommodation expenses, for their considerable effort.
The membership of the NJR Steering Committee and membership of and attendance at meetings for all sub-committees for 2012/13 can be found online (Appendix Four).
1.3.2 NJR Steering Committee
In July 2012, the NJR Steering Committee held a workshop with invited stakeholders to examine how the NJR governance and operating model should evolve to remain fit for the future. The four key components of the workshop were: agree the purpose of the NJR over the next ten years; agree and prioritise the activities needed to support the purpose; assess the capabilities necessary to deliver the activities and consider the committee structure necessary to support the delivery of those activities.
Having agreed the mission statement included at Section 1.1.1, the workshop agreed the following priorities:
•Improving data quality
•Improving data access, data availability and data linkage
•Supporting research - internal and external
•Effective stakeholder communications and patient and public engagement
•Extending the benefits of the NJR - new joints, new geographical areas
•Greater international collaboration as the largest arthroplasty register in the world
•Supporting cost effectiveness and value for money
•Outcomes reporting and identifying best and worst practice and
•Providing a ‘rapid response’ service - bespoke reactive analysis of NJR data
It is clear that, as the NJR has matured over its first ten years, the NJR’s governance structure and its resources, designed for a simpler set of activities and outputs, could not be sustained with an increasing work load, a growing list of strategic priorities, changes in the healthcare environment, greater stakeholder expectations, and rapidly increasing international interest and collaboration.
In order to ensure that appropriate focus on all areas of business was maintained, decisions could be made in a timely and efficient manner, representation included all major stakeholders, resource capacity was appropriate to the effort required, and that roles and responsibilities were clearly defined, the following updates to the NJR’s operating model were considered:
•The creation of a new NJR Executive Committee to provide strategic leadership and decision making in a more effective manner, and tasking the Steering Committee to handle operational matters
•The creation of a new medical advisory committee
•The appointment of a new post of NJR Medical Director
•Ensuring that the sub-committee structure is fit for purpose and can deliver the objectives
•Ensuring that the relationship between committees and activities is transparent
•Increasing committee capacity through the recruitment of new members and the involvement of NJR RCC Network in what has previously been steering committee and sub-committee business
•Ensuring patient involvement in steering committee and sub-committee business
•Supporting the NJR’s standing committee structure, by convening ad-hoc working groups to work on specific issues and areas of concern of NJR development, with clear direction, specified outcomes, timelines and budgets
•Ensuring that all committees and working groups have clear terms of reference, an agreed composition, and defined purposes and responsibility, and that members have clearly defined roles and terms of office
The work to define and agree the final operating model will continue in 2013/14 with the final operating model being submitted to DH for its consideration and
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endorsement. Once that has been achieved, the final structure will reflect the interactions and relationships between the various committees and will include detailed terms of reference for the committees and their members.
1.3.3 NJR Editorial Board - Mr Martyn Porter, Chairman
The composition and role of the Editorial Board remains unchanged from 2011/12. Its main role is to ensure that the Annual Report is produced on time, for wider distribution at the British Orthopaedic Association (BOA) Congress in the autumn, and to ensure that it is reviewed in detail and quality assured. In 2013/14, to celebrate the 10th anniversary of the NJR, there will be an independent event to launch the report’s findings.
The overall publication process is managed by HQIP. Parts One and Two, focusing on annual progress and clinical activity, are managed by the NJR Centre (Northgate Information Solutions), particularly with the help of Mike Swanson and Claire Newell. Part Three, outcomes after joint replacement is produced by the University of Bristol team, particularly with the help of Professor Ashley Blom, Michèle Smith and Linda Hunt (statistical lead). Part Four, Trust- and unit-level activity is a joint contribution from the NJR Centre and the University of Bristol.
The Editorial Board meets five times a year and has several teleconferences with a significant part of the editorial work carried out by email. We meet shortly after the BOA Congress to discuss the response to the recently launched report, to consider feedback and start planning for the next report publication. We then have a teleconference in March to review the progress of the previous year’s special topics and to plan the special topics for the coming year. The meeting in April is to update the Editorial Board regarding the production of the Annual Report and consider the timelines and actions that need to be taken. In May we meet to review the early outputs of Parts One to Four and to consider the format, tables, content and accuracy. There are then two further review stages before we meet in early July to approve the content before formal sign off at the July NJR Steering Committee meeting.
The secondary roles of the Editorial Board include identification of special topics and in-depth studies. It is recognised that the timelines to produce the Annual Report are often very tight and more detailed work takes a longer period to obtain the necessary outputs. Recent in-depth topics have included analysis of resurfacing, metal-on-metal hip replacements and this year includes a study of mortality. There are plans to study infection and revision operations in more detail. All these studies are planned and monitored through the Research Sub-committee to prevent duplication, overlap and inconsistency.
NJR Fellowship Programme
The first two NJR Fellows, Mr Simon Jameson and Mr Paul Baker, who were appointed for one year, have worked with the Editorial Board and published a range of papers on aspects of both hip and knee replacement in peer review journals. They have also worked in collaboration with the University of Bristol but more often with their local mentors and academic supervisors in their places of routine clinical activity. They have both been extremely motivated and both presented and published their work which is listed in the appendices. A further update on the NJR Fellowship programme is included at 1.4.11.
Annual Report Development Strategy
It is important that the Editorial Board recognise the changes necessary with emerging technology. We have established a working group which will consider greater emphasis to online and, where possible, real time reporting and, possibly, a shorter hard copy of the report. We are also considering more interactive modes of obtaining information.
We are also considering holding a Research Day where the outputs and publications from the NJR can be presented and discussed in more detail.
Public and Patient Guide
In conjunction with the HQIP communications team and, in particular, Rebecca Beaumont, the Editorial Board oversees the production of the Public and Patient Guide which was first launched in 2011. We will continue to develop this important output and the 2012 edition included important patient-friendly developments (see 1.4.5).
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BOA Congress
The Editorial Board also work with the British Orthopaedic Association where they provide at least one instructional session at the Annual Congress. In 2013/14, we will be fortunate to have three sessions as part of the programme.
1.3.4 Implant Performance Sub-committee - Mr Keith Tucker, Chairman
The Implant Performance Sub-committee essentially embraces two committees. The main committee includes the members of the Scrutiny Group together with representatives from the implant manufacturing industry. The composition of the Scrutiny Group includes representatives from the NJR Steering Committee, the Medicines and Healthcare products Regulatory Agency (MHRA), HQIP, Northgate Information Solutions and the University of Bristol.
It is the Scrutiny Group’s brief to analyse and assess the confidential data that relates to implants that have come under performance review (potential outliers). A performance review can be triggered by verbal or written communication, a paper or presentation at a surgical meeting or a report from another joint registry. Most commonly a review results from analysis of our own data where the Patient Time Incidence Rate (PTIR) has been found to be unacceptably high. The PTIR is the revision rate per 100 observed years and is calculated by the statistical team in Bristol from the data prepared by Northgate. The PTIR for every implant is measured twice yearly.
We are reviewing our methodology at present but essentially when an implant has a PTIR of twice the group PTIR (Level 1) a report is filed with the MHRA. When the PTIR is only 1.5 times the group PTIR, a warning letter is sent to the company (Level 2). Over the past year there have been two Level 1 reports and fourteen Level 2 reports.
Since this committee has been in existence we have picked up outlier performance which has involved ‘mix and match’. This is where components of a hip replacement are made by more than one manufacturer. Examples include a stem being made by Company A and the acetabular component by
Company B. There have not been any examples of outlier performance when the articulation has been ‘hard on soft’ (such as a metal or ceramic head articulating with a high density polyethylene cup or liner) but there have been two Level 1 reports and nine Level 2 reports for combinations which involve ‘hard on hard’ (such as metal-on-metal).
We keep a close watch on some, usually relatively new prostheses, where concern has been raised in other countries. For example, during the past year, there have been some concerns expressed by one manufacturer with regard to a femoral component which incorporates a modular neck – this was showing up as an outlier in the Australian Registry. We have looked carefully at all the NJR data for implants with modular necks and compared this to use in some other countries, but surgeons recorded on the NJR have not made a lot of use of modular necks prostheses in hip replacement.
Looking to the future, the committee feels it is time that we turned our attention to revision prostheses. The NJR has about 76,000 revisions logged into the database. Anecdotally we know that some revision procedures do better than others. The implants are often (but not always) extremely expensive. There are also issues about whether surgical experience and volume have a part to play in outcomes. In our view, a fully comprehensive assessment of these implants is now due.
My thanks go to all the committee for their dedication and hard work - it is one of the great strengths of the NJR that it has the ability to monitor device performance in this manner, to facilitate outlier device investigation by both the regulator and manufacturers. Thanks too must go to Melissa Wright (HQIP) for her organisation and note keeping.
1.3.5 Surgeon Outliers Sub-committee - Professor Paul Gregg, Chairman
The Outliers Sub-committee (surgical data) met three times in 2012/13. The committee’s role is to ensure that, at the earliest stage, concerns about potential outlier performance of units and surgeons is highlighted and communicated to those concerned.
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It is important to emphasise that the identification of a potential outlier surgeon does not mean that a surgeon’s performance is poor as many other contributing factors may have influence, for example, type of implant used, case-mix and incomplete provision of data to the NJR. All of these factors have been seen to contribute to potential outlier performance in some cases.
The first Annual Clinical Reports to NHS Trusts, Local Health Boards and independent providers were sent out in September 2012 and the reports contained the following data:
•Compliance rate as a percentage
•Consent rate as a percentage
•Linkability rate as a percentage
•A ‘traffic light’ system indicating their performance against these indicators: green, amber, red
In addition:
•Unit mortality ratio (reported as Standardised Mortality Ratio (SMR) with a ‘traffic light’ system)
•Unit revision rate for hips and knees (reported as Standardised Revision Ratio (SRR) with a ‘traffic light’ system)
•Individual surgeon (anonymised) revision rates for hips and knees
In addition, the SRR’s are shown on funnel plots for all units and surgeons with individual funnel plots for all hips, cemented hips, uncemented hips, resurfacing/MoM hips, hybrid hips, all knee replacements, cemented knee replacements, uncemented knee replacements, unicondylar knee replacements and patello-femoral knee replacements.
In the event of a surgeon being identified as a ‘potential outlier’ (SRR > 99.8% control limit), a letter is sent to the surgeon six weeks before the Annual Clinical Report is sent, informing him/her of the situation and enclosing the data upon which the potential outlying status had been calculated. This is to allow the surgeon opportunity to validate the data which the NJR holds for them. Separate notification of the identity of a potential outlying surgeon is made to the CEO at the time of sending the Annual Clinical Report.
In the case of surgeons known to have retired, be on long-term sick leave, moved abroad or left the Trust or Local Health Board, a letter would also be sent to the CEO for notification.
For private units, letters are sent to the Group CEO who would forward the letter to the appropriate general manager.
Future reports will be sent out in April/May each year to coincide with the new financial year.
Six months after the dissemination of the Annual Clinical Reports, the data is scrutinised and if additional potential outlier units or surgeons are identified, the relevant CEO is informed six weeks after notifying the surgeon.
CEOs are asked to acknowledge receipt of the report and, if there is no response after a second communication, the Care Quality Commission (CQC in England or NHS Wales) is informed. The latter has only been necessary for two Trusts following the first distribution of Annual Clinical Reports.
Two CQC representatives attended one of the sub-committee meetings in order for the NJR to share with them our current approach to managing potential outlier units and surgeons. The CQC will continue to work with the NJR to determine how our data can form part of the CQC Quality Risk Profiles information and be used in their hospital inspection process in England.
In some cases, surgeons had been identified as potential outliers because of their use of specific prostheses known to have poor results and which, subsequently, have been removed from the market. It had been agreed that three years after a prosthesis has been removed from the market due to poor results, those cases would be removed from the database of all surgeons and their SRR re-calculated. In the three years interim, funnel plots would be shown with the withdrawn prosthesis in and a plot with the withdrawn prosthesis out.
The committee also noted for 2012/13 the difficulties encountered in an audit of Trusts to seek further clarification of the performance of the Pinnacle acetabular cup when used with a metal liner. Despite
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a letter being sent to 13 Trusts in July 2012 by Sir Bruce Keogh, NHS Medical Director, instructing them to take part, only eight responded by March 2013 and only four of those had completed the data collection. The matter was escalated to the CQC to follow up on behalf of the NJR. The audit has now been completed for 12 of the 13 units and a report on the outcomes provided to the MHRA and NHS England.
After extensive discussions it has been agreed that, to give greater clarity on the sub-types of joint replacement, the next Annual Clinical Reports will show separate funnel plots for units and surgeons as follows:
Knees
•All types of knee replacements together
•Total knee replacement cemented
•Total knee replacement uncemented/hybrid
•Unicondylar knee replacement
•Patello-femoral knee replacement
Hips
•All types of hip replacement together
•Total hip replacement cemented
•Total hip replacement uncemented
•Hybrid and reverse hybrid total hip replacement
•Resurfacing and metal-on-metal total hip replacement
It is important to remember that the success and validity of this outlier process relies heavily on the diligence of Trusts, Local Health Boards, independent providers and surgeons entering all primary and revision procedures. It is the surgeon’s, independent provider’s, Local Health Board’s and Trust’s responsibility to make sure that all cases are registered and accurate. Participation in the NJR has been mandatory since April 2011 for NHS hospitals and since April 2003 for the independent sector. Surgeons are advised to check regularly with the NJR Clinician Feedback System to ensure the data held by NJR are accurate. This will become increasingly important with the impending publication of named surgeon implant
survivorship statistics, as part of NHS England’s transparency agenda.
Thanks are expressed to the members of the committee for their time and contribution to this important, but sometimes challenging, process. The Chair wishes to extend particular thanks to the significant amount of work undertaken by Mr Peter Howard in connection with many of the analyses.
1.3.6 NJR Research Sub-committee - Professor Alex MacGregor, Chairman
The Research Sub-committee’s remit is to maximise access to NJR for the wider research community whilst upholding the quality of research based on NJR data. The committee takes formal responsibility for the release of data for research through an impartial and objective protocol and has oversight of the use and reporting of NJR data by research groups.
During the period 2012/13, the committee sanctioned the release of data to six external research groups. These included data released for analysis that will inform the revised NICE guidance for total hip and surface replacement. The committee received an unprecedented number of expressions of interest for future project work from both the UK and overseas, some of which has been submitted for external funding. We encourage any researcher planning externally funded work with the NJR to discuss their proposals in confidence with the NJR in advance of submission. Full details of the NJR’s research data access policy and protocols, together with detailed guidance notes for applicants, can be found at www.njrcentre.org.uk.
The research profile of the NJR has continued to expand over the last year, with over 40 presentations to national and international scientific meetings. A total of 18 scientific papers have been published in peer reviewed literature for this reporting year, based on work carried out by the NJR statistical analysis team at the University of Bristol and by academic groups working on data releases that were sanctioned by the committee.
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Notable publications in this period include a British Medical Journal (BMJ) paper outlining the most extensive contemporary analysis of the cost-effectiveness of cemented, cementless and hybrid prostheses for total hip replacement. Also published in the BMJ, an analysis using NJR-HES linked data of cancer risk in the seven years after metal-on-metal joint replacement provided the first registry based evidence of the absence of increased cancer risk following surgery. Findings published in the Lancet showed an inferior implant survivorship for metal-on-metal resurfacing in women when compared to other surgical options. This year also saw the first set of analyses to include NJR data linked to PROMs.
A full list of publications related to NJR data is included in Appendix Two. The redesigned research library section of our website catalogues all NJR research data releases with their progress reports, together with links to all publications related to NJR data.
1.3.7 NJR Data Quality Group - Professor Paul Gregg, Chairman
A Data Quality Sub-committee was established in 2012 and met once during this reporting year 2012/13.
Although there has been a gradual and progressive improvement in compliance, consent and linkability since the start of the registry, there was still concern about the compliance with the registration of both primary and revision joint replacement by some Trusts despite being made mandatory in April 2011. The terms of reference were to explore methods of improving data capture and quality.
It was decided to try and establish a named data quality person for each provider who would be responsible on an annual basis, for providing the numbers of procedures performed to the NJR for cross-checking and validation.
A letter was sent to provider CEOs explaining that, as part of their compliance with the NJR, a data quality process was being created and it was therefore being requested that they provide the name and contact details of their nominated data quality returns person. An instruction sheet was sent with the letter outlining what was required from the nominated person and providing advice regarding any coding issues they may come across. The NJR website would list each provider’s nominated person.
It is disappointing to report that only 55 responses were received from 151 letters which were sent to all Trusts in England, Welsh Local Health Boards, and private sector groups. Chase letters were sent to all CEOs of non-responding providers, with copies to Medical Directors, and failure to respond will lead to a third and final letter being sent to provider CEOs to state that any data from their units that appeared in the public domain would be un-validated as the NJR had not received a named representative. A list of providers that have not supplied a data quality representative will appear in future NJR Annual Reports.
In addition to the above, a data accuracy audit is being planned across 20 orthopaedic units under the direction of the Regional Clinical Coordinators (RCCs). A sample set of 30 patients (15 hips, 15 knees with 5 of each set being revisions) will be studied in each of the units. This study will look at the accuracy of data entry onto the NJR Minimum Dataset (MDS) form (comparing with notes, theatre logs etc.) and accuracy of transcription from the NJR MDS form to the database.
It should be recorded that three previous data accuracy studies have shown encouraging results for the accuracy of the main data fields.
I would like to thank the members of the sub-committee for their contributions and the RCC Network for undertaking the proposed audit of data accuracy.
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1.3.8 NJR Regional Clinical Coordinators’ (RCC) Network – Mr Peter Howard, Chairman
As Chair of the Regional Clinical Co-ordinators Network since 2007, I am aware of the significant achievements this group has made in supporting the raising of the profile of the NJR to fellow clinicians and acting as the key link in communicating NJR activities to hospital managers and other relevant hospital staff.
Working with our respective Regional Coordinators this year, the Network has, as always, been keen to understand the specific concerns of individual hospitals in relation to their NJR responsibilities. Although there continue to be issues with some Trusts, there are clear improvements within this area.
The RCCs have been vital to understanding specific issues regarding data quality by initiating unit-level audits of NJR data. This work feeds into the strategic actions of the Data Quality Group and will become an ongoing function of the Network.
This year also saw a substantial review of the MDS. The RCCs were able to input into the list of proposed changes to the dataset and help create a priority group of actions to be implemented into the relevant NJR forms in the coming months.
Once again, the RCC Network has supported the development of the Patient and Public Guide to the Annual Report by ensuring key messages from the main report are distilled accurately to enable patients to be clear about the key outcomes of joint replacement surgery.
As my time as Chair of the RCC Network comes to an end, I would like to thank all of the surgeons who have put themselves forward for this role and their individual efforts in championing the NJR at a local level.
Part 11.4 Highlights
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This section provides a brief summary of the work and activities undertaken by the NJR during 2012/13.
1.4.1 Geographic extension of the NJR
From February 2013, hospitals in Northern Ireland started to submit data to the NJR. Some system development was necessary to accommodate a patient identifier different to the NHS number used in NHS Trusts in England and Welsh Local Health Boards. The Healthcare Number (HCN) allocated to patients in Northern Ireland is retained and used if those patients subsequently receive treatment in either England or Wales. The NJR already has many HCN numbers recorded for patients who have had joint replacement surgery. This means that it will be possible to get a more accurate assessment of outcomes where patients may have had a primary joint replacement procedure in Northern Ireland and a subsequent revision in either England or Wales. It is hoped that the benefits that the NJR brings for patients, surgeons, and healthcare management will be recognised by independent providers.
It is hoped that units in both the Isle of Man and Jersey will start submitting data to the NJR in 2013/14.
1.4.2 Extension of the NJR: Elbows and shoulders
From 1 April 2012, the NJR started to collect data about elbow and shoulder joint replacement procedures. The project was supported by the British Elbow and Shoulder Society (BESS).
The NJR Steering Committee has also agreed to a two-year pilot in which PROMs, using Oxford Shoulder Scores, will be collected from patients who have undergone a shoulder replacement procedure at six months following surgery. Pre-operative Oxford Shoulder Scores are collected as part of the primary shoulder data set. The follow-up will be with NHS-funded patients only in England and Wales.
1.4.3 Beyond Compliance: ‘Protecting Patients, Supporting Innovation’
For a manufacturer to market a joint replacement in Europe, the device must have been awarded a CE mark (Conformité Européene). CE marks are categorised
according to the perceived risk inherent in the device. Until 2008 joint replacement implants were graded as Class 2b. Total hip, knee, and shoulder replacement have since been re-classified to Class 3. CE marks are awarded by Notified Bodies. Each European State has one or more Notified Body which is supervised by the appropriate competent authority in each country, e.g. the MHRA in the United Kingdom.
The CE Mark is “Compliance”. It is illegal for anyone to hinder the sale of a product with a CE mark. The CE mark is, to a very considerable extent, awarded on the basis of ‘Equivalence’. Until now manufacturers have sometimes claimed equivalence in more than two features of the design. Equivalence could have been claimed in the material, shape, lubrication system etc., whilst at the same time claiming the product is a new and important addition to the market. To obtain a Class 3 CE Mark, the manufacturer has also to outline a post-market surveillance plan. Despite CE regulations, devices have been introduced into the market that have proven to be poor. Even with NJR, ODEP, MHRA and the CE Mark, there are examples of implants falling short of expectations. This has frustrated many for a considerable period.
Mr Peter Kay, during his time in office as BOA President, developed the concept of Beyond Compliance. Implicit in Beyond Compliance is the invitation to a manufacturer to go beyond the demands of the CE mark and enter into a process that will offer greater rigour and organisation than that currently available through the CE process. It is proposed that Beyond Compliance, whilst remaining an entirely voluntary process, could be used with all new implants and modifications to established devices.
Beyond Compliance embraces two main features and is governed by a Steering Committee. The first feature is an Advisory Group service and the second, a very sophisticated post-CE mark online surveillance service. ODEP has been asked to take the lead with Beyond Compliance and the panel agreed to set up the advisory service and the monitoring process last year at the invitation of the BOA and MHRA. NHS Supply Chain is responsible for the administrative organisation of the process.
The Advisory Group’s first duty is to look at the detailed product file provided by the manufacturer. The Advisory
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Group will then assess the level of residual risk there might be with this product. The manufacturer’s post-marketing surveillance plan, including post-market clinical follow-up studies, will also be reviewed. With the manufacturer, the group will discuss and agree the rate at which the device could enter the market and add any other comments they think appropriate. Following that decision there will also be agreement on a plan for post-market clinical follow-up, which will be monitored with the implanting surgeons and manufacturer representatives.
Any implant selected for the process is notified to the NJR Centre which will then create a record for the implant in a central data repository. When the record of a procedure is submitted to the NJR in the normal way, the system will automatically recognise a Beyond Compliance device and copy the procedure details to that central repository. The repository will
also receive details of those procedures where the device has been revised.
The NJR Centre will also be able to add procedure level data from HES, PEDW, and the NHS England national PROMs programme. Surgeons will be able to upload additional data such as x-rays, operation notes and video. Suppliers will also be able to upload pre-CE Mark data and results from follow-up studies.
Not only will surgeons, suppliers, and Advisory Group members be able to access all the data relating to a specific implant, a number of automated reports will also be available, enabling them to monitor the performance of that implant. Additionally, there will be a number of additional services, such as providing suppliers with the ability to undertake follow-up studies with patients. The flow of data and information is shown in the figure below:
Figure 1.2 Beyond Compliance data flow.
Surgeons
NJR Centre
Hospitals
SuppliersAdvisory Group
Reports and Additional Services
Central Data Repository
Operation NotesOperation Video
X-Rays
Pre-CE Mark DataBibliography
Follow-Up Study Data
NJR Procedure DataNJR Primary/Revision Linked Data
HES, PEDW, PROMs
© N
atio
nal J
oint
Reg
istr
y 20
13
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Should the results of a device going through the Beyond Compliance process prove to be unsatisfactory, the MHRA will be informed immediately.
Through this project, NJR data will be used to assist in the monitoring of new devices with a view to detecting problems earlier, if they occur, and to help promote good practice with a system of sophisticated post-market surveillance. Presently, with the involvement of NJR, the development of this project is a world first. Our progress to date has stimulated discussion for the use of a Beyond Compliance system for other devices such as breast implants and heart valves.
Please visit www.beyondcompliance.co.uk or contact Mr Keith Tucker for further details.
It is appropriate to acknowledge the enthusiasm and huge amount of preparatory work that Northgate Information Solutions have put into this project.
1.4.4 Publication of consultant-level data
In December 2012, the NHS England CEO, Sir David Nicholson, announced plans for nine surgical specialties and one medical specialty to start publishing consultant-level activity and outcomes information by June 2013. Orthopaedics was one of the specialties included and the NJR will be used as the source of outcomes data for hip and knee joint replacement and will provide a web-based portal for the publication of this information. The NJR is working closely with the lead specialty association British Orthopaedic Association in their discussions with NHS England and HQIP to ensure that the requirements are understood and in order to obtain consent from those consultant surgeons registered with the NJR to publish their data. The data will be made available at www.njrsurgeonhospitalprofile.org.uk.
1.4.5 Patient-focused initiatives
A second edition of the NJR’s Public and Patient Guide to the Annual Report was published in 2012/13 with notable improvements in content and design as well as a choice of online formats - a standard PDF
or interactive version. These ideas and suggestions were taken forward from the workshops at the Patient Focus conference in 2012 and came to fruition through the newly established NJR Patient Network. The Public and Patient Guide has again been awarded the Information Standard logo, a quality mark for evidence-based information supported by the Department of Health.
The NJR Patient Network has grown over the year, meeting twice to share views and to get to know the NJR and its work in more detail. Members have helped to shape the recently revised patient information leaflet and new poster for hospital waiting areas and are currently involved in the development of a patient implant card pilot project. The NJR would like to thank all members for their thoughts, comments and time spent contributing to the registry’s progress.
The Network is a significant development for the registry and the group will be a firm feature in the NJR’s structure and work programme in the future. All of the registry’s patient-focused initiatives continue to be supported and championed at NJR Steering Committee through patient representatives Mary Cowern and Sue Musson.
1.4.6 NJR Feedback Services: Updates
NJR Clinician Feedback
The Steering Committee agreed to a project to implement further reports in NJR Clinician Feedback following the preparation of a set of prioritised requirements by the RCC Network. These high level requirements to be delivered are:
•A plot track for individual surgeons on the Patient Time Incidence Rate report (PTIR) enabling surgeons to identify either improving or worsening outcomes. The PTIR report will also be able to be run as ‘Lead Surgeon’ enabling either trainee surgeons to assess outcomes where they were the lead surgeon or enabling consultant surgeons to separate those procedures where they were the lead surgeon from those procedures where a trainee was the lead surgeon.
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•The current Revision Rate reports will be updated to include revision rates at five and seven years. As for the PTIR report, the Revision Rate report will be extended to include ‘Lead Surgeon’ in addition to ‘Consultant in Charge’.
•Surgeons will be provided with further information about their patients whose primary procedures have been revised by another surgeon and, potentially, in another hospital. The reasons for revision and time to latest endpoint will be provided along with sufficient information for the primary surgeon to identify the patient and, if necessary, review patient notes. Surgeons will also be able to download and print the primary procedure details submitted to the NJR for those patients.
•Surgeons will also be provided with an Annual Summary report for the purposes of the revalidation process, very similar to the Annual Clinical Report.
NJR Management Feedback
•NJR Management Feedback is used to produce the Annual Clinical Report which was sent to units for the first time in September 2012. The report is available as a download from NJR Management Feedback and is accessible by anyone in the unit authorised to do so by senior management.
NJR Supplier Feedback
•NJR Supplier Feedback is a unique, procedure-level online data reporting system to enable manufacturers to perform post-marketing surveillance on their range of implants. Improvements to the Supplier Feedback system are being considered to broaden reporting to revision hips and knees as well as shoulder, elbow and ankle joints. Linkage to PROMs data for primary hips and knees is planned, along with the development of additional online analysis tools.
1.4.7 Proposed changes to the Minimum Dataset
The NJR Steering Committee has also approved the development of the Minimum Dataset to the next version, MDSv6. The changes are not major and
reflect, for example, recent developments in chemical thromboprophylaxis, the need to carry out different types of analyses, removing inconsistencies between the data forms, and the requirement to improve data quality by removing ambiguity and changing system defaults. The development will take place later in 2013/14 once the changes have been approved by the NHS Information Standards Board.
1.4.8 Price Benchmarking
Quality, Innovation, Production, and Protection (QIPP) is a large transformational programme for the NHS which aims to improve the quality of care provided by the NHS whilst, at the same time, making up to £20 billion of efficiency savings by 2014/15 which will be invested in frontline care. QIPP Procurement is a workstream of the QIPP programme and aims to help NHS provider Trusts reduce and optimise non-pay expenditure without compromising quality of patient treatment and care.
Orthopaedic joint replacement implants represent relatively high cost and high volume procurement within this category and are, therefore, subject to particular focus. Orthopaedic implants are purchased locally or regionally across England and Wales. Each purchasing authority negotiates pricing with suppliers based upon local conditions and purchase volumes. As a result of this local procurement model, there are variations in pricing for orthopaedic implants across NHS England and NHS Wales. With funding from the Department of Health, the Price Benchmarking project aims to highlight this price variation in England and Wales. Following a successful pilot in 2012/13 with three purchasing authorities, the pilot project was widened to other authorities and will continue to expand in 2013/14. Early indications are that there are, in some instances, significant price variations for some prostheses and that the volume of purchases does not necessarily attract appropriate discounts. This information will become more widely available in the latter stages of the project roll out via an online reporting tool.
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1.4.9 International developments
The NJR is regularly approached and asked to take part in a conference or symposium to support greater international collaboration and we are keen to share our experiences across the globe.
International Society of Arthroplasty Registers (ISAR)
The NJR was certainly not the first joint registry. The Scandinavians, in particular, were many years ahead with Australia becoming an important member some 13 years ago. New Zealand was not long following and there are now about 18 countries with national joint registries in varying stages of development. The USA has a relatively embryonic national registry but also has a number of registries which tend to be regional. Italy has three registries and a national registry project.
ISAR was set up in 2004 essentially between the Scandinavian and Australian registries. The NJR joined two years ago and are now full members. The idea behind the foundation was to encourage registries to communicate with each other and form data linkages – we know that there is much to learn from each other.
ISAR had its first Congress in Bergen during May 2012 and, following its success, the management board asked the NJR to host ISAR 2013 in the UK. It is a great honour to showcase the NJR’s progress and developments, welcome a plethora of experience and, of course, have access to Continuing Professional Development (CPD) on one’s own doorstep. The ISAR working group chose Stratford-upon-Avon as the host town, knowing it would produce an excellent ambience for the meeting.
The current President of ISAR is Göran Garellick and Mr Martyn Porter will be President 2014/15 following the American Academy of Orthopaedic Surgeons (AAOS) meeting in February 2014.
International Consortium of Orthopaedic Registries (ICOR)
The ICOR initiative was launched in 2011, essentially as a response to the problems of metal-on-metal hip replacement in the US. It was promoted by the US Food and Drugs Administration (FDA) and launched
with an inaugural conference at their headquarters in Silver Springs, Maryland. The meeting was attended by representatives of most national joint registries. Since then ICOR has promoted several collaborative audits and reports. The NJR is represented on the ICOR committee by Keith Tucker.
The US FDA and the European Commission are driving the Unique Device Identifier (UDI) initiative which the NJR is fully supporting. Eventually all implants will have a UDI (usually entrenched in their bar-code) which will relate to an internationally agreed component database.
ICOR grant bursaries for research associated with registry data and are willing to fund travelling fellowships. For more information, contact Art Sedrakyan whose details can be found on the ICOR website (www.icor-initiative.org).
1.4.10 Patient Reported Outcomes Measures (PROMs)
The NJR reported the results from its first PROMs survey in the 2nd Annual Report in 2005. This study was carried out in a group of 20,000 patients who had previously undergone replacement of a hip or knee joint. The NJR initiated a second more extensive one year follow-up PROMs programme in 2011. In order to be eligible for the study, patients had to have completed a pre-operative questionnaire for the NHS England national PROMs programme and have consented to have their personal details held by the NJR. Over a six-month period, 50,000 questionnaires were sent to patients, with approximately 42,500 being returned completed. With about 1,500 patients being lost to follow-up since the start of the programme, approximately 41,000 Year Three follow-up questionnaires will be despatched over a six-month period which began in March 2013. It is intended to undertake a further follow-up project at five years following surgery.
The data from the Year One follow-up is currently being examined and will be linked to both pre- and post-operative data from the NHS England PROMs programme, NJR data and HES data. The team from the University of Bristol, along with Steering Committee member Professor Alex MacGregor, will undertake the analysis of the data.
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1.4.11 NJR Fellowships
Following the excellent work undertaken by the previous two NJR Fellows, the NJR advertised the availability of another Fellowship in the latter half of 2012. Following interview, Mr Jeya Palan has been appointed and is due to start his Fellowship in April 2013. His work will be directed by the NJR Research Sub-committee and he will be supported by the team at the University of Bristol looking at issues in relation to unicompartmental knee replacement in addition to revision hip and knee replacements. Another NJR Fellowship will be advertised later in 2013.
1.4.12 Orthopaedic Data Evaluation Panel (ODEP) overview
The ODEP group was set up to monitor NICE guidance on primary hip implants in 2002 and hip resurfacing in 2004. Although ODEP is independent from the NJR, its Chairman Keith Tucker is also a member of the NJR Steering Committee and the NJR provides data to facilitate the monitoring process. The NJR also uses ODEP outputs in a number of published reports. The panel provides an ongoing assessment of hip implants to benchmark both hip femoral stems and hip acetabular cups against the NICE guidance, providing a benchmark rating for implant survivorship and submitted data quality. The ODEP rating is now a commonly used benchmark not only in the UK but globally. A full list of products submitted to the panel and their individual ratings can be found at www.odep.org.uk.
The group is hosted by NHS Supply Chain and members, listed below, volunteer their time and expertise:
•Keith Tucker – Chairman of ODEP - Consultant orthopaedic surgeon from Norwich
•Peter Kay – Consultant orthopaedic surgeon, Wrightington, Wigan and Leigh NHS Foundation Trust.
•Philip Lewis – NHS Supply Chain
•Martin Pickford – Northgate, orthopaedic advisor to the NJR
•Andy Smallwood – Procurement Wales
•Evert Smith – Consultant orthopaedic surgeon, North Bristol NHS Trust
•Ian Stockley – Consultant orthopaedic surgeon, Sheffield Teaching Hospitals NHS Foundation Trust
The panel has recently started the assessment of required criteria for the evaluation of knee implants which will follow a similar process of data submission and evaluation to the hip products. In order to gain the expert knowledge required for this field we have recruited the following members:
•Colin Esler – Consultant orthopaedic surgeon, University Hospitals of Leicester NHS Trust
•Richard Parkinson – Consultant orthopaedic surgeon, Wirral University Teaching Hospital NHS Foundation Trust
•Andrew Porteous – Consultant orthopaedic surgeon, North Bristol NHS Trust
•Andrew Toms – Consultant orthopaedic surgeon, Royal Devon and Exeter NHS Foundation Trust
•Timothy Wilton – Consultant orthopaedic surgeon, Derby Hospitals NHS Foundation Trust
The panel members accept data submissions for hips bi-annually in spring and autumn with monthly meetings arranged to discuss and review improvements to the process scheduled throughout the year.
The year 2012 saw a marked increase in the level of activity of the panel with the numbers of submissions being provided for benchmark reaching 108 and the start of three major activities:
•Initiation of a full review of the hip benchmarking process
•Introduction of a benchmarking process for knees
•Formation of the Beyond Compliance Advisory Group (see 1.4.3)
Plans for 2013/14 will see the full launch of the revised hip process, submissions from industry to gain a knee benchmark and the completion of the pilot phase of the Beyond Compliance initiative. In addition, improvements to access of information with the launch of a new website and, in recognition of the importance placed on ODEP, introducing further programme support.
1.5 Finance
Part 1
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1.5.1 Income and expenditure 2012/13
The NJR is self financing, funded by a levy raised on the sale of hip, knee, ankle, shoulder, and elbow implants to NHS and independent healthcare providers in England, Wales, and Northern Ireland (the latter from February 2013). The rate of the levy is recommended by the NJR Steering Committee for approval by the Department of Health (DH), and is subject to a Memorandum of Understanding between the DH, Welsh Government, Health and Social Care Board Northern Ireland, Independent Healthcare Advisory Services and the Association of British Healthcare Industries (ABHI) Orthopaedics Special Interest Section.
The levy was set at £20.00 per joint from 1 April 2012 to 31 March 2013. Levy income in 2012/13 was £3,292,579 (2011/12: £3,131,630). Expenditure for the same period was £2,512,741 (2011/12: £2,831,850).
Total expenditure for members’ expenses during 2012/13 was £8,337 (2011/12: £26,069).
Below are some of the 2012/13 costs associated with the major NJR project areas:
•Shoulder PROMs £46,750 (total cost of project £116,950)
•Hospital Management Feedback £14,950 (total cost of project £49,950)
•Geographical extension of the NJR £39,083 (total cost of project £146,750)
•Clinician Feedback Phase Two £70,500 (total cost of project £141,650)
•Price Benchmarking Phase One £49,705 (total cost of project £49,705)
The NJR’s financial results are included in the audited accounts of HQIP (Healthcare Quality Improvement Partnership) which manages the registry. The full audited accounts are available on HQIP’s website from September 2013 (www.hqip.org.uk), and also from the Charity Commission, and Companies House.
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Laurel Powers-Freeling Chairman (from April 2011)
Professor Paul Gregg Vice ChairmanActing Chairman (October 2009 to March 2011)Orthopaedic Surgeon (from October 2002)
Mr Mick Borroff Orthopaedic device industry (from October 2002)
Mary Cowern Patient Representative. Patient group – Arthritis Care (from October 2006)
Dr Jean-Jacques de Gorter Independent healthcare sector (from October 2011)
Professor Alex MacGregor Public health and epidemiology (from October 2002)
Sue Musson Patient representative (from October 2011)
Carolyn Naisby Practitioner with special interest in orthopaedics (from July 2006)
Mr Martyn Porter Orthopaedic surgeon (from January 2003)
Dean Sleigh Orthopaedic device industry (from April 2008. Resigned in February 2013)
Mr Keith Tucker Orthopaedic surgeon (from May 2007)
Andrew Woodhead NHS Trust management (from January 2007)
A1.2 Membership from April 2012
Members are appointed as posts become vacant.
Appendix 1 NJR Steering Committee 2012/13
A1.1 NJR Steering Committee – Composition
As a department expert committee, the composition of the NJRSC by category is:
•Chairman 1
•Orthopaedic surgeons 3
•Patient representatives 2
•Implant manufacturer/supplier industry 2
•Public health/epidemiology 1
•NHS organisation management 1
•Independent healthcare provider 1
•Practitioner with special interest in orthopaedic care who is a GP, nurse or allied 1 health professional (physiotherapist or occupational therapist)
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Laurel Powers-Freeling No interests to declare
Professor Paul Gregg Emeritus Consultant Orthopaedic Surgeon, James Cook University Hospital, Middlesbrough, Professor of Orthopaedic Surgical Science, Orthopaedic Advisor for Ramsay Healthcare
Mick Borroff Chair, ABHI Orthopaedics Special Interest Section Employed by DePuy International Ltd, manufacturer of orthopaedic prostheses
Mary Cowern Wales Director for the UK charity Arthritis Care
Dr Jean-Jacques de Gorter Director of Clinical Services, Spire Healthcare
Professor Alex MacGregor Professor of Genetic Epidemiology, University of East Anglia Consultant Rheumatologist, Norfolk and Norwich University Hospital NHS Trust
Sue Musson Managing Director, Firecracker Projects Limited (supplying management consultancy to NHS organisations) Non-Executive Director, Bridgewater Community NHS Trust
Carolyn Naisby Consultant Physiotherapist, City Hospitals Sunderland NHS Foundation Trust
Mr Martyn Porter Consultant Orthopaedic Surgeon, Wrightington, Wigan and Leigh NHS Trust (orthopaedic unit has received financial support from DePuy International for clinical and RSA studies for Elite Plus femoral stem and C-Stem). Has acted as a consultant to DePuy International in relation to the development of a hip femoral stem (C-Stem AMT) and received royalties on this hip stem
Mr Dean Sleigh ABHI Council member, ABHI Orthopaedics Special Interest Section
Mr Keith Tucker Consultant orthopaedic surgeon, NorwichRoyalties received from Johnson & Johnson Orthopaedics more than five years ago for contribution to design of hip prostheses (all royalties paid into an orthopaedic charity)
Andrew Woodhead Head of Mergers and Acquisitions, NHS London (until 31 March 2012)Managing Director - Andrew Woodhead Consulting Ltd (from Oct 2012)Associate Consultant - Deloitte (from Oct 2012) Associate Consultant - Verita (from Nov 2012)Trustee - Guideposts Charity (from July 2013)
Mr Peter Howard Chairman of the NJR Regional Clinical Coordinators’ Network
Dr Crina Cacou Senior Medical Device Specialist, MHRA
Andy Smallwood Procurement Wales
Elaine Young National Development Lead, HQIP
Robin Burgess Chief Executive, HQIP
Robin Rice Welsh Government
A1.3 Observers
The following have regularly attended NJR Steering Committee meetings as observers:
A1.4 Members’ declarations of interest
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Appendix 2 List of papers, publications and research requests using NJR data
This appendix provides details of published analyses and data releases that have been sanctioned by the NJR Research Sub-committee between April 2012 and March 2013. NJR data is available for research purposes following approval by the NJR Research Sub-committee. For further details please visit the NJR website at www.njrcentre.org.uk.
Published papers (April 2012 to March 2013)
Factors Influencing Revision Risk Following 15,740 Single-Brand Hybrid Hip Arthroplasties: A Cohort Study From a National Joint RegistryJameson SS, Mason JM, Baker PN, Jettoo P, Deehan DJ, Reed MR. J Arthroplasty. 2013 Mar 21. pii: S0883-5403(13)00108-3. doi: 10.1016/j.arth.2012.11.021.
Cemented, cementless and hybrid prostheses for total hip replacement: a cost-effectiveness analysisPennington M, Grieve R, Sekhon JS, Gregg PJ, Black N, van der Meulen JH. BMJ. 2013 Feb 27;346:f1026. doi: 10.1136/bmj.f1026.
Mid-term survival following primary hinged total knee replacement is good irrespective of the indication for surgeryBaker P, Critchley R, Gray A, Jameson S, Gregg P, Port A, Deehan D. Knee Surg Sports Traumatol Arthrosc. 2012 Dec 14.
Mid-term equivalent survival of medial and lateral unicondylar knee replacement: an analysis of data from a National Joint RegistryBaker PN, Jameson SS, Deehan DJ, Gregg PJ, Porter M, Tucker K. J Bone Joint Surg Br. 2012 Dec;94(12):1641-8. doi: 10.1302/0301-620X.94B12.29416.
The design of the acetabular component and size of the femoral head influence the risk of revision following 34,721 single-brand cemented hip replacements: a retrospective cohort study of medium-term data from a National Joint RegistryJameson SS, Baker PN, Mason J, Gregg PJ, Brewster N, Deehan DJ, Reed MR. J Bone Joint Surg Br. 2012 Dec;94(12):1611-7. doi: 10.1302/0301-620X.94B12.30040.
Failure rates of metal-on-metal hip resurfacings: analysis of data from the National Joint Registry for England and WalesSmith AJ, Dieppe P, Howard PW, Blom AW; National Joint Registry for England and Wales. Lancet. 2012 Nov 17;380(9855):1759-66. doi: 10.1016/S0140-6736(12)60989-1.
Patient and implant survival following 4323 total hip replacements for acute femoral neck fracture: a retrospective cohort study using National Joint Registry dataJameson SS, Kyle J, Baker PN, Mason J, Deehan DJ, McMurtry IA, Reed MR. J Bone Joint Surg Br. 2012 Nov;94(11):1557-66. doi: 10.1302/0301-620X.94B11.29689.
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Appendix 2 List of papers, publications and research requests using NJR data
Revision following patello-femoral arthoplastyBaker PN, Refaie R, Gregg P, Deehan D. Knee Surg Sports Traumatol Arthrosc. 2012 Oct;20(10):2047-53.
Revision for unexplained pain following unicompartmental and total knee replacementBaker PN, Petheram T, Avery PJ, Gregg PJ, Deehan DJ. J Bone Joint Surg Am. 2012 Sep 5;94(17):e126.
The association between body mass index and the outcomes of total knee arthroplastyBaker P, Petheram T, Jameson S, Reed M, Gregg P, Deehan D. J Bone Joint Surg Am. 2012 Aug 15;94(16):1501-8.
Reason for revision influences early patient outcomes after aseptic knee revisionBaker P, Cowling P, Kurtz S, Jameson S, Gregg P, Deehan D. Clin Orthop Relat Res. 2012 Aug;470(8):2244-52. doi: 10.1007/s11999-012-2278-7.
The effect of surgical factors on early patient-reported outcome measures (PROMs) following total knee replacementBaker PN, Deehan DJ, Lees D, Jameson S, Avery PJ, Gregg PJ, Reed MR. J Bone Joint Surg Br. 2012 Aug;94(8):1058-66. doi: 10.1302/0301-620X.94B8.28786.
The effect of aspirin and low molecular weight heparin on venous thromboembolism after knee replacement: A non-randomised comparison using National Joint Registry data Jameson SS, Baker PN, Charman SC, Deehan DJ, Reed MR, Gregg PJ, van der Meulen JH. J Bone Joint Surg Br. 2012 Jul;94(7):914-8.
Comparison of patient-reported outcome measures following total and unicondylar knee replacement Baker PN, Petheram T, Jameson SS, Avery PJ, Reed MR, Gregg PJ, Deehan DJ. J Bone Joint Surg Br.2012 Jul;94(7):919-27.
Patient Reported Outcome Measures after revision of the infected Total Knee Replacement: Do patients prefer single or two-stage revision? Baker P, Petheram TG, Kurtz S, Konttinen YT, Gregg P, Deehan D. Knee Surg Sports Traumatol Arthrosc. 2012 June 13.
Independent predictors of revision following metal-on-metal hip resurfacing: A retrospective cohort study using National Joint Registry data Jameson SS, Baker PN, Mason J, Porter ML, Deehan DJ, Reed MR. J Bone Joint Surg Br. 2012 Jun;94(6):746-54.
Risk of cancer in first seven years after metal-on-metal hip replacement compared with other bearings and general population: Linkage study between the National Joint Registry for England and Wales and hospital episode statisticsSmith AJ, Dieppe P, Porter M, Blom AW; National Joint Registry of England and Wales. BMJ. 2012 Apr 3;344:e2383. doi: 10.1136/bmj.e2383.
Total hip replacement for the treatment of acute femoral neck fractures: results from the National Joint Registry of England and Wales at 3-5 years after surgery Stafford GH, Charman SC, Borroff MJ, Newell C, Tucker JK. Ann R Coll Surg Engl. 2012 Apr;94(3):193-8. doi: 10.1308/003588412X13171221589720.
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Approved requests for NJR data for research (April 2012 to March 2013)
Rate of venous Thromboembolism in total ankle arthroplasty Zaidi R Royal National Orthopaedic Hospital NHS Trust, Stanmore February 2013
Does the type of venous thromboembolism (VTE) chemoprophylaxis influence the rate of revision for infection following primary hip and knee replacement?Baker P Health Education North East January 2013
Total hip replacement and surface replacement for the treatment of pain resulting from end stage arthritis of the hip (Review of technology appraisal guidance 2 and 44)Clarke A Warwick Medical School, University of Warwick December 2012
Understanding failure in unicompartmental knee arthroplastyMurray DW Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford November 2012
Revision rates by prosthesis type: parametric survival analysis to inform a model of cost-effectivenessDanielson V Johnson & Johnson Medical November 2012
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Appendix 3Additional information on the NJR websitewww.njrcentre.org.ukThe following information will also be available on the NJR website:
1. NJR 10th Annual Report - Parts One, Two, Three and Four (annual progress 2012/13, clinical activity 2012, implant survivorship 2003 to 2012, and Trust- and unit-level activity and outcomes 2012)
2. NJR 10th Annual Report - Part One: Annual Progress 2012/13 – Welsh Language
3. NJR 10th Annual Report - NJR Steering Committee and Sub-committee composition and attendance 2012/13
4. NJR 10th Annual Report - NJR Steering Committee Terms of Reference
5. NJR 10th Annual Report - NJR Regional Clinical Coordinators’ Terms of Reference
6. NJR 10th Annual Report - Prostheses Data
7. NJR 10th Annual Report - Tables and Figures
8. NJR 10th Annual Report - Public and Patient Guide
2.1 Introduction
Part 2Clinical activity 2012
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This section summarises the number of hip, knee and ankle replacement procedures undertaken in England and Wales between 1 January and 31 December 2012 and entered into the NJR by 28 February 2013. Details of elbow and shoulder procedures submitted between 1 April and 31 December 2012 and submitted into the NJR by 28 February 2013 are also included. The information is summarised according to the type of hospital or treatment centre, procedure type and patient characteristics.
2.1.1 Hospitals and treatment centres participating in the NJR
A total of 413 orthopaedic units were open and of these 398 (96%) submitted at least one hip, knee, ankle, elbow or shoulder procedure to the NJR (Table 2.1). During the life of the NJR there has been a trend showing a greater proportion of all hip replacements being performed in larger centres. However, in 2012 the proportion of large volume centres has remained constant but the percentage of medium sized centres (200-299) has increased by 3% (Figure 2.1).
On average, 218 hip replacements and 235 knee replacements were recorded per orthopaedic unit over the year, although the numbers varied from 1 to 1,490 procedures for any one joint type. Compared with previous years, there was a decrease in the number of units performing more than 400 knee procedures (Table 2.2) but a large increase in the number of units performing 300-400 knee procedures. Most units performing ankle procedures perform less than 5 in a year but there are four units doing larger volumes.
The nine months of recording elbow and shoulder replacements show that most units do less than 5 elbow procedures in nine months whereas more than half the units do more than 5 shoulder procedures in nine months.
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Table 2.1 Total number of hospitals and treatment centres in England and Wales able to participate in the NJR and the proportion actually participating in 2012.
Total number of units Number of units submitting Proportion participatingTotal 413 398 96%
NHS hospitals 240 225 94%
England 222 207 93%
Wales 18 18 100%
Independent hospitals 163 163 100%
England 157 157 100%
Wales 6 6 100%
ISTC 10 10 100%
England 10 10 100%
Wales - - -
Table 2.2 Number of participating hospitals, according to number of procedures performed during 2012.
Total number of
hospitals
Number of procedures
<50 50 - 99 100 - 199 200 - 299 300 - 399 400+Hip procedures
Hospitals entering replacements 396 48 68 109 73 55 43
Hospitals entering primary replacements 396 57 70 119 77 41 32
Knee procedures
Hospitals entering replacements 386 43 47 115 64 61 56
Hospitals entering primary replacements 386 49 46 120 69 57 45
Total number of
hospitals
Number of procedures
<5 5 - 9 10 - 14 15 - 19 20 - 24 25+Ankle procedures
Hospitals entering replacements 140 106 20 7 3 0 4
Hospitals entering primary replacements 136 104 20 5 3 2 2
Elbow procedures
Hospitals entering replacements 109 95 10 2 2 0 0
Hospitals entering primary replacements 101 93 6 2 0 0 0
Shoulder procedures
Hospitals entering replacements 241 114 52 25 17 12 21
Hospitals entering primary replacements 238 115 57 28 11 15 12
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Hip procedures
0%
100%
80%
60%
40%
20%
Per
cent
age
of h
osp
itals
Knee procedures
Year
400+
300 - 399 200 - 299 100 - 199 50 - 99 <50Number of hospitalsTotal hip procedures
4%8%
18%31%21%19%
393
63,948
2005
7%8%
14%29%22%20%
399
66,703
2006
9%10%
18%25%23%15%
391
74,878
2007
10%9%
17%31%17%15%
394
78,183
2008
8%12%
17%31%18%13%
395
78,918
2009
7%
13%27%23%28%
392
53,306
2004
3%
2010
10%11%
19%27%19%15%
400
81,623
2012
11%14%
18%28%17%12%
396
86,488
2011
11%14%
16%29%18%12%
398
84,892
0%
100%
80%
60%
40%
20%
Per
cent
age
of h
osp
itals
Year
400+ 300 - 399
200 - 299 100 - 199
50 - 99 <50Number of hospitalsTotal kneeprocedures
5%8%
14%33%
20%19%
391
64,042
2005
8%9%
12%24%
25%22%
398
66,207
2006
12%11%
14%25%
19%19%
389
78,106
2007
13%10%
15%31%
15%15%
390
82,477
2008
12%14%
17%29%
15%14%
393
84,148
2009
4%
11%25%
24%32%
393
48,937
2004
4%
2010
14%12%
17%26%
18%13%
392
86,974
2012
15%16%
17%30%
12%11%
386
90,842
2011
16%10%
18%29%
14%11%
392
89,837
Figure 2.1 Percentage of participating hospitals by number of procedures per annum, 2004 to 2012.
2.2 Hip replacement procedures 2012
Part 2
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The total number of hip procedures entered into the NJR during 2012 was 86,488, an increase of 7% over 2011. Of these, 76,448 were primary and 10,040 were revision procedures. The revision ‘burden’ increased on the 2011 levels by 1% to 12%.
Table 2.3 shows that 93% of patients at independent hospitals and ISTCs were graded as fit and healthy or with mild disease according to the ASA system, compared with 78% at NHS units.
Nearly all procedures (94%) undertaken at ISTCs were primary procedures. The percentage of primary hip
resurfacings has decreased again this year to 1% of all primary procedures. The percentage of resurfacing procedures done in Independent hospitals (3%) is triple that of NHS hospitals (1%), as shown in Figure 2.2. Independent units and ISTCs perform more cementless hip primary procedures than NHS hospitals.
At NHS hospitals, revision procedures account for 14% of all procedures. In comparison, the revision burden at independent hospitals is 7%.
5 Bilaterals will only be counted as a bilateral if they are entered under the same operation during data entry. If the two procedures are recorded under two different operations they will be counted as two unilateral procedures. Therefore, the count of bilaterals is likely to be an underestimate.
Table 2.3 Procedure details, according to type of provider for hip procedures in 2012.
NHS hospitalsIndependent
hospitals ISTC Total
No. % No. % No. % No. %Total hip procedures 61,044 71% 22,415 26% 3,029 4% 86,488 Patient physical status
P1 - fit and healthy 6,977 11% 4,703 21% 381 13% 12,061 14%
P2 - mild disease not incapacitating 40,955 67% 16,139 72% 2,421 80% 59,515 69%
P3 - incapacitating systemic disease 12,565 21% 1,541 7% 227 7% 14,333 17%
P4 and P5 547 <1% 32 <1% - 0% 579 <1%
Procedure type
Primary procedures 52,675 69% 20,927 27% 2,846 4% 76,448 88%Primary total prosthetic replacement using cement
18,756 36% 5,614 27% 946 33% 25,316 33%
Primary total prosthetic replacement not using cement
21,985 42% 10,566 50% 1,592 56% 34,143 45%
Primary total prosthetic replacement not classified elsewhere (e.g. hybrid)
11,399 22% 4,203 20% 305 11% 15,907 21%
Primary resurfacing arthroplasty of joint 535 1% 544 3% 3 <1% 1,082 1%
Revision procedures 8,369 83% 1,488 15% 183 2% 10,040 12%
Hip single-stage revision 7,236 86% 1,405 94% 171 93% 8,812 88%
Hip stage one of two-stage revision 514 6% 39 3% 7 4% 560 6%
Hip stage two of two-stage revision 563 7% 43 3% 5 3% 611 6%
Hip excision arthroplasty 56 <1% 1 <1% 0 0% 57 <1%
Bilateral or unilateral5
Bilateral 214 <1% 152 <1% 2 <1% 368 <1%
Unilateral 60,830 100% 22,263 100% 3,027 100% 86,120 100%
Funding
Independent 697 1% 10,078 45% 5 <1% 10,780 12%
NHS 60,347 99% 12,337 55% 3,024 100% 75,708 88%
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Figure 2.2 Primary hip procedures by type of provider 2012.
2.2.1 Primary total hip replacement procedures (THR) 2012
Of the 76,448 primary hip replacement procedures undertaken in 2012, 33% were cemented THRs, 43% were cementless, 1% were hip resurfacing procedures and 2% were large head metal-on-metal (LHMoM) THRs (Figure 2.3). For the first time the number of operations for the current reporting year available for this report is greater than the previous year. Normally, this is not the case as not all procedures performed in the reporting year are submitted in time to be reported in the Annual Report. It is too soon to tell whether this is due to an increase in activity, an increase in compliance, more timely submissions or a combination of these factors.
The ratio between cemented and cementless
procedures has continued to change in 2012. In 2011, there was a 5% difference and in 2012 this increased to 10% more cementless procedures than cemented procedures being carried out. There has been an increase in the percentage of hybrid (standard and reverse hybrid) procedures performed. There has also been a significant decrease in the percentage of resurfacing procedures and in procedures where a large metal head is used with a resurfacing cup (LHMoM). This decline is thought to have resulted from the well publicised voluntary recall of one brand of resurfacing device (ASR – DePuy) and ongoing concerns regarding the safety of LHMoM procedures as reflected in MHRA guidance and follow-up.
In 2012, 15% of hybrid procedures were reverse hybrid (cementless stem, cemented socket) and 85% were standard hybrid (cemented stem, cementless socket).
0%
20%
40%
60%
80%
100%
Type of provider
Per
cent
age
of p
roce
dur
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pe
Cemented 36% 27% 33%
Cementless 42% 50% 56%
Hybrid 22% 20% 11%
Resurfacing 1% 3% <1%
52,675 20,927 2,846
NHS hospitals
Independent hospitals ISTCs
Number of procedures
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Figure 2.3 Type of primary hip replacement procedures undertaken between 2005 and 2012.
2.2.1.1 Patient characteristics
Age and gender were included for those patients who gave consent for their personal identifiers to be entered into the NJR and where consent was ‘Not recorded’ (a total of 96%). The average age was 67.4 years, 0.2 years more than last year. Approximately 60% of the patients were female (Table 2.5) which is the same as 2011. On average, female patients were older than male patients at the time of their primary hip replacement (69.7 years and 67.2 years respectively, Table 2.5). Patients undergoing a resurfacing procedure were the youngest, at an average age of 53.4 years (Table 2.5). Seven times as many males have a resurfacing procedure compared with females.
According to the ASA system, 15% of patients undergoing a primary hip replacement in 2012 were graded as fit and healthy prior to surgery, compared with 37% in 2003. Figure 2.6 shows the changes in ASA grade over ten years. Patient BMI6 has increased over the past eight years from 27.4 to 28.7, as shown in Figure 2.7. Females undergoing THR have a consistently lower mean BMI than males; the converse is the case for TKR (Figure 2.22). Figure 2.7 shows that there has been an increase in the number of patients with a BMI of between 30 and 39 and a decrease in the number of patients with BMI between 20 and 24. The single largest indication recorded for surgery was osteoarthritis, recorded in 92% of procedures (Table 2.4). Figure 2.5 shows that the percentage of patients within the age group bands has not changed
0%
10%
20%
30%
40%
50%
60%
Year
Per
cent
age
of p
roce
dur
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pe
Cemented
Cementless
Hybrid
Resurfacing
Large head metal- on-metal (≥36mm)
Number of procedures
54%
22%
12%
9%
3%
56,454
2005
46%
25%
14%
10%
6%
59,967
2006
43%
27%
14%
9%
7%
67,321
2007
38%
32%
15%
8%
8%
70,559
2008
36%
37%
15%
6%
6%
70,908
2009
36%
41%
16%
3%
5%
73,006
2010
36%
41%
18%
2%
3%
75,460
2011
33%
43%
20%
1%
2%
76,448
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6 BMI: 20-24 normal, 25-29 overweight, 30-39 obese, 40+ morbidly obese.
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significantly since 2003, suggesting that the increase in BMI and reduction in fitness of patients is not due to an ageing patient cohort. However, only 16% of entries in 2005 had BMI data entered (BMI was not collected as
part of MDSv1) and, while this has increased to 67% in 2012, all BMI data has to be viewed with caution as surgeons may be more likely to enter BMI data when the BMI is high, introducing an element of bias.
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Table 2.4 Patient characteristics for primary hip replacement procedures in 2012, according to procedure type.
Primary total prosthetic
replacement using cement
Primary total prosthetic
replacement not using cement
Primary total prosthetic
replacement not classified elsewhere
(e.g. hybrid)
Primary resurfacing
arthroplasty of joint Total
No. % No. % No. % No. % No. %
Total hip primaries 25,316 33% 34,143 45% 15,907 21% 1,082 1% 76,448
Patient physical status
P1 - fit and healthy 2,433 10% 6,145 18% 2,011 13% 503 46% 11,092 15%P2 - mild disease not incapacitating
17,730 70% 23,860 70% 11,064 70% 545 50% 53,199 70%
P3 - incapacitating systemic disease
4,975 20% 4,019 12% 2,717 17% 34 3% 11,745 15%
P4 and P5 178 <1% 119 <1% 115 <1% 0 0% 412 <1%
BMI
Number with BMI data 17,084 67% 22,694 66% 10,775 68% 747 69% 51,300 67%
Average 28.35 29.08 28.54 28.09 28.71
SD 5.20 5.34 5.35 4.32 5.29
Indications for surgery
Osteoarthritis 23,123 91% 31,837 93% 14,192 89% 1,036 96% 70,188 92%
Avascular necrosis 570 2% 828 2% 486 3% 11 1% 1,895 2%
Fractured neck of femur 1,035 4% 645 2% 759 5% 1 0% 2,440 3%Congenital dislocation/Dysplasia of the hip
171 <1% 758 2% 254 2% 28 3% 1,211 2%
Inflammatory arthropathy 340 1% 409 1% 262 2% 10 <1% 1,021 1%
Failed hemiarthroplasty 60 <1% 45 <1% 67 <1% 0 0% 172 <1%
Trauma - chronic 370 1% 333 <1% 264 2% 15 1% 982 1%Previous surgery - non trauma related
47 <1% 142 <1% 60 <1% 1 <1% 250 <1%
Previous arthrodesis 16 <1% 14 <1% 10 <1% 0 0% 40 <1%
Previous infection 22 <1% 25 <1% 17 <1% 3 <1% 67 <1%
Other 379 1% 386 1% 288 2% 18 2% 1,071 1%
Side
Bilateral 42 <1% 228 <1% 80 <1% 14 1% 364 <1%
Left, unilateral 11,273 45% 15,487 45% 7,215 45% 529 49% 34,504 45%
Right, unilateral 14,001 55% 18,428 54% 8,612 54% 539 50% 41,580 54%
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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Table 2.5 Age and gender for primary hip replacement patients in 2012.
Primary total prosthetic
replacement using cement
Primary total prosthetic
replacement not using cement
Primary total prosthetic
replacement not classified elsewhere
(e.g. hybrid)
Primary resurfacing
arthroplasty of joint Total
No. % No. % No. % No. % No. %Total hip primaries
25,316 33% 34,143 45% 15,907 21% 1,082 1% 76,448
Total hip primaries with patient data
24,570 97% 32,827 96% 15,290 96% 958 89% 73,645 96%
Average age 73.1 65.2 70.0 53.4 68.7
SD 9.6 11.4 11.0 9.6 11.4Interquartile range
67.6 – 79.8 58.4 – 73.2 63.9 – 77.7 47.5 – 59.9 62.2 – 76.9
Average age by gender
Female 16,162 66% 18,176 55% 9,682 63% 120 13% 44,140 60%
Average 73.66 65.77 70.75 52.69 69.70
SD 9.47 11.35 10.79 9.74 11.10Interquartile range
68.2 - 80.3 59.0 - 73.7 64.7 - 78.4 47.9 - 58.6 63.4 - 77.7
Male 8,408 34% 14,651 45% 5,608 37% 838 87% 29,505 40%
Average 72.14 64.48 68.75 53.52 67.20
SD 9.65 11.40 11.20 9.56 11.60Interquartile range
66.5 - 78.9 57.7 - 72.5 62.4 - 76.1 47.4 - 60.2 60.4 - 75.6
Age group by gender
Female
<30 years 20 <1% 118 <1% 30 <1% 3 3% 171 <1%
30 - 39 years 63 <1% 287 2% 67 <1% 8 7% 425 <1%
40 - 49 years 204 1% 1,176 6% 306 3% 32 27% 1,718 4%
50 - 59 years 983 6% 3,390 19% 1,001 10% 53 44% 5,427 12%
60 - 69 years 3,777 23% 6,523 36% 2,838 29% 22 18% 13,160 30%
70 - 79 years 6,864 42% 5,051 28% 3,561 37% 1 <1% 15,477 35%
80 - 89 years 3,972 25% 1,558 9% 1,729 18% 1 <1% 7,260 16%
90+ 279 2% 73 <1% 150 2% 0 0% 502 1%
Male
<30 years 12 <1% 116 <1% 30 <1% 11 1% 169 <1%
30 - 39 years 39 <1% 298 2% 61 1% 52 6% 450 2%
40 - 49 years 182 2% 1,146 8% 261 5% 220 26% 1,809 6%
50 - 59 years 595 7% 3,013 21% 761 14% 339 40% 4,708 16%
60 - 69 years 2,278 27% 5,309 36% 1,708 30% 189 23% 9,484 32%
70 - 79 years 3,569 42% 3,761 26% 2,001 36% 24 3% 9,355 32%
80 - 89 years 1,638 19% 976 7% 752 13% 3 <1% 3,369 11%
90+ 95 1% 32 <1% 34 <1% 0 0% 161 <1%
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Table 2.6 Indications for hip primary procedure based on age groups.
Indication
<30 years30-39 years
40-49 years
50-59 years
60-69 years
70-79 years
80-89 years 90+
No. % No. % No. % No. % No. % No. % No. % No. %
Total hip primaries by age group
340 875 3,527 10,135 22,644 24,832 10,629 663
Osteoarthritis 150 44% 552 63% 2,996 85% 9,348 92% 21,219 94% 23,227 94% 9,756 92% 567 86%Avascular necrosis
81 24% 155 18% 237 7% 314 3% 394 2% 363 1% 245 2% 34 5%
Fractured neck of femur
4 1% 6 <1% 27 <1% 180 2% 598 3% 895 4% 450 4% 31 5%
Congenital dislocation/Dysplasia of the hip
75 22% 182 21% 333 9% 272 3% 194 <1% 68 <1% 17 <1% 1 <1%
Inflammatory arthropathy
31 9% 33 4% 100 3% 164 2% 312 1% 249 1% 94 <1% 8 1%
Failed hemi-arthroplasty
2 <1% 10 1% 7 <1% 20 <1% 43 <1% 67 <1% 16 <1% 0 0%
Trauma - chronic
12 4% 26 3% 81 2% 148 1% 236 1% 226 <1% 175 2% 27 4%
Previous surgery, non trauma related
23 7% 41 5% 58 2% 46 <1% 31 <1% 27 <1% 8 <1% 1 <1%
Previous arthrodesis
5 1% 1 <1% 4 <1% 5 <1% 12 <1% 6 <1% 5 <1% 1 <1%
Previous infection
8 2% 10 1% 7 <1% 9 <1% 13 <1% 14 <1% 4 <1% 0 0%
Indication other
41 12% 63 7% 128 4% 146 1% 215 <1% 248 1% 142 1% 23 3%
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Figure 2.4 Age and gender for primary hip replacement patients in 2012.
Resurfacing 2%
Hybrid 18%
Cementless 69%
Cemented 12%
Female
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
roce
dur
es
<30Age group
171 2%
16%
68%
15%30-39
4252%
18%
68%
12%40-49
1,718<1%
18%
62%
18%50-59
5,427<1%
22%
50%
29%60-69
13,160<1%
23%
33%
44%70-79
15,477<1%
24%
21%
55%80-89
7,2600%
30%
15%
56%90+
502Number of patients
Resurfacing 7%
Hybrid 18%
Cementless 69%
Cemented 7%
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
roce
dur
es
<30Age group
16912%
14%
66%
9%30-39
45012%
14%
63%
10%40-49
1,8097%
16%
64%
13%50-59
4,7082%
18%
56%
24%60-69
9,484<1%
21%
40%
38%70-79
9,355<1%
22%
29%
49%80-89
3,3690%
21%
20%
59%90+
161Number of patients
Male
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Figure 2.5 Age for primary hip replacement patients between 2003 and 2012.
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
atie
nts
in
each
age
ban
d
50-5940-4930-39<30
90+80-8970-79
16%4%1%
2003
<1%
14,557
<1%13%33%31%
15%5%1%
2004
<1%
28,222
<1%13%33%31%60-69
Number ofpatients
Year
16%5%1%
2005
<1%
40,370
<1%13%34%31%
15%5%1%
2006
<1%
47,687
<1%13%34%30%
15%5%1%
2007
<1%
60,637
<1%13%34%31%
15%5%1%
2008
<1%
66,892
<1%13%34%30%
14%5%1%
2009
<1%
67,729
<1%14%34%30%
14%5%1%
2010
<1%
69,900
<1%14%34%30%
14%5%1%
2012
<1%
73,645
<1%14%34%31%
14%5%1%
2011
<1%
72,537
<1%14%34%31%
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Figure 2.6 ASA grades for primary hip replacement patients between 2003 and 2012.
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
atie
nts
P4 and P5P3P2P1
<1%9%
53%
2003
37%
26,435
<1%11%57%
2004
31%
48,061
<1%13%60%
2005
26%
57,594
<1%13%63%
2006
23%
59,967
<1%13%66%
2007
20%
67,322
<1%13%69%
2008
18%
70,559
<1%14%69%
2009
17%
70,908
<1%15%69%
2010
16%
73,006
<1%15%70%
2012
15%
76,448
<1%15%70%
2011
15%
75,461Number ofpatients
Year
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2.2.1.2 Surgical techniques
The surgical techniques used in procedures in 2012 are summarised in Table 2.7. Patients were mainly positioned laterally. The lateral position was used more frequently in hybrid and resurfacing procedures than in cemented and cementless procedures. As would be expected, the most frequently used incision approach was posterior for all procedure types, though for cemented procedure types there were nearly as
many procedures performed where a lateral (including Hardinge) approach was used.
The reduction in the use of cemented stems (from 77% in 2004 to 51% in 2012) and also in the use of cemented cups (from 56% to 36%) is consistent with the reduction seen in the overall number of cemented procedures and a corresponding increase in hybrid and cementless surgery. The change in 2012 appears to have been mainly caused by the rapid decline
Figure 2.7 BMI for primary hip replacement patients between 2004 and 2012.
25
26
27
28
30
29
BM
I
Per
cent
age
of p
atie
nts
0%
60%
50%
40%
30%
20%
10%
Year 2004 2005 2006 2007 2008 2010 2011
BMI 30-34
BMI 15-19
BMI 20-24
BMI 25-29
Average BMI- all patients
BMI 35-39
BMI 40-44
BMI 45+
2009
Average BMI- female
Average BMI- male
27.36
3%
27%
40%
21%
6%
2%
<1%
27.29
27.71
17%
5,919
27.47
3%
27%
40%
21%
6%
2%
<1%
27.15
27.87
16%
9,002
27.67
3%
25%
40%
21%
7%
2%
<1%
27.53
27.94
18%
10,473
27.91
3%
24%
40%
23%
8%
2%
<1%
27.77
28.16
21%
14,237
28.31
2%
21%
41%
25%
8%
2%
<1%
28.12
28.62
48%
33,842
28.43
2%
21%
40%
25%
9%
2%
<1%
28.22
28.72
56%
39,431
28.53
2%
20%
40%
25%
9%
2%
<1%
28.31
28.83
60%
43,679
28.60
2%
20%
40%
26%
9%
2%
<1%
28.40
28.92
64%
48,345
2012
28.71
2%
19%
40%
26%
10%
3%
<1%
28.49
29.04
67%
51,300
Percentage of prwith BMI
with BMI
ocedures
Number of procedures
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in metal-on-metal procedures rather than a switch from one type of conventional hip replacement to another since 2004 (Figure 2.3). The relative usage of different types of bone cement is shown in Figure 2.8 and shows that the use of antibiotic cement has
increased from 73% in 2004 to 89% in 2012. Use of minimally-invasive surgery was greatest in cementless procedures, although it was used in less than 5% of all procedures (Table 2.7) which is the same as 2011.
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Table 2.7 Surgical technique for primary hip replacement patients in 2012.
Primary total
prosthetic replacement
using cement
Primary total prosthetic
replacement not using cement
Primary total prosthetic
replacement not classified
elsewhere (e.g. hybrid)
Primary resurfacing
arthroplasty of joint Total
No. % No. % No. % No. % No. %Total hip primaries
25,316 33% 34,143 45% 15,907 21% 1,082 1% 76,448
Patient position
Lateral 22,965 91% 31,864 93% 15,303 96% 1,077 100% 71,209 93%Supine 2,351 9% 2,279 7% 604 4% 5 <1% 5,239 7%
Incision Lateral (inc. Hardinge)
10,131 40% 10,878 32% 4,092 26% 133 12% 25,234 33%
Posterior 13,731 54% 21,185 62% 11,157 70% 916 85% 46,989 61%Trochanteric osteotomy
310 1% 26 <1% 11 <1% 13 1% 360 <1%
Other 1,144 5% 2,054 6% 647 4% 20 2% 3,865 5%
Minimally-invasive surgery
Yes 478 2% 2,884 8% 365 2% 14 1% 3,741 5%No 24,838 98% 31,259 92% 15,542 98% 1,068 99% 72,707 95%
Image-guided surgery
Yes 32 <1% 158 <1% 31 <1% 33 3% 254 <1%No 25,284 100% 33,985 100% 15,876 100% 1,049 97% 76,194 100%
Bone graft used - femur
Yes 173 <1% 400 1% 44 <1% 13 1% 630 <1%No 25,143 99% 33,743 99% 15,863 100% 1,069 99% 75,818 99%
Bone graft used - acetabular
Yes 1,014 4% 1,321 4% 841 5% 79 7% 3,255 4%No 24,302 96% 32,822 96% 15,066 95% 1,003 93% 73,193 96%
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2.2.1.3 Thromboprophylaxis
Patients may receive more than one chemical and more than one mechanical thromboprophylaxis method. The most frequently prescribed chemical method of thromboprophylaxis for hip replacement patients was low molecular weight Heparin (LMWH), at 73%, and the most used mechanical method was TED stockings
(66%), (Table 2.8). There has been a marked decrease over the past years in the use of aspirin, 20% in 2009 to 8% in 2012. Direct thrombin inhibitor is now used in 13% of hip primary procedures and the use of ‘other chemical’ has gone up from 7% in 2009 to 13% in 2012. The number of procedures for which both chemical and mechanical methods were prescribed has continued to rise from 63% in 2007 to 92% in 2012.
Figure 2.8 Bone cement types for primary hip replacement procedures undertaken between 2004 and 2012.
Number of procedures
0%
50%
40%
30%
20%
10%
60%
70%
80%
90%
Year
Per
cent
age
of p
roce
dur
es
Antibiotic-loadedhigh viscosity
Antibiotic-loadedmedium viscosity
Antibiotic-loadedlow viscosity
High viscosity
Medium viscosity
Low viscosity
34,497
62%
2004
6%
5%
7%
19%
<1%
40,473
65%
2005
7%
4%
6%
17%
<1%
40,544
65%
2006
8%
3%
6%
18%
<1%
44,334
65%
2007
9%
3%
5%
17%
<1%
43,362
68%
2008
9%
3%
5%
15%
<1%
41,108
74%
2010
10%
2%
4%
11%
<1%
43,789
79%
2012
9%
1%
2%
8%
<1%
43,359
77%
2011
9%
1%
3%
9%
<1%
41,514
70%
10%
2%
5%
13%
<1%
2009
using cement
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2.2.1.4 Untoward intra-operative events
Untoward intra-operative events were reported in 1.3% of procedures (Table 2.9). Of the 999 untoward events reported, a decrease of 9 events compared with 2011, 33% were attributed to calcar crack.
As would be expected, this occurred more often in cementless than in cemented hips. Furthermore, 16% were trochanteric fractures, also more common in cementless procedures. 36% of events were of ‘other’ description.
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Table 2.8 Thromboprophylaxis regime for primary hip replacement patients, prescribed at time of operation.
Total
No. %
Total hip primaries 76,448
Aspirin 6,124 8%
Low molecular weight Heparin (LMWH) 55,713 73%
Pentasaccharide 1,148 2%Warfarin 557 <1%
Direct thrombin inhibitor 10,203 13%Other chemical 9,583 13%
No chemical 2,143 3%Foot pump 20,159 26%
Intermittent calf compression 33,052 43%TED stockings 50,713 66%
Other mechanical 2,272 3%No mechanical 3,679 5%
Both mechanical and chemical 70,700 92%Neither mechanical nor chemical 36 <1%
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Table 2.9 Reported untoward intra-operative events for primary hip replacement patients in 2012, according to procedure type.
Primary total
prosthetic replacement
using cement
Primary total prosthetic
replacement not using cement
Primary total prosthetic
replacement not classified
elsewhere (e.g. hybrid)
Primary resurfacing
arthroplasty of joint Total
No. No. No. No. No.
Total hip primaries 25,316 34,143 15,907 1,082 76,448
Event specified 273 517 206 3 999
Calcar crack 28 239 61 0 328
Pelvic penetration 44 24 19 0 87
Shaft fracture 13 22 11 0 46
Shaft penetration 6 14 1 0 21
Trochanteric fracture 56 61 39 0 156
Other 126 157 75 3 361
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2.2.1.5 Hip primary components
This section outlines in more detail the trends in brand usage for hips. For a full listing of brands used in 2012, please visit the NJR website at www.njrcentre.org.uk. This section also includes an analysis of usage according to National Institute for Health and Care Excellence (NICE) guidelines, as interpreted by the Orthopaedic Data Evaluation Panel (ODEP).
2.2.1.5.1 Compliance with ODEP and NICE guidelines
In 2012, 101 brands of acetabular cup, 8 brands of resurfacing cup and 146 brands of femoral stem were used in primary and revision procedures and recorded on the NJR. This is a decrease in the number of brands of acetabular cup and stem in use compared with 2011.
The 2nd NJR Annual Report in 20047 gave a full description of the NICE guidance on the selection of prostheses for primary THRs and metal-on-metal hip resurfacing arthroplasty. It also described the establishment of ODEP. Its remit is to provide an independent assessment of clinical evidence, submitted by suppliers, on the compliance of their implants for THR and hip resurfacing against NICE benchmarks for safety and effectiveness. ODEP produced detailed criteria for this guidance which is currently under review as part of a complete overhaul of the system.
The ODEP committee have reviewed suppliers’ clinical data submissions and ODEP ratings have been given to 69 brands of femoral stem (50% of those available) and 49 brands of acetabular cup (49%) used in primary procedures. However, there are 39 brands of acetabular cup (39%) and 46 brands of femoral stem (33%) currently being used in England and Wales for which no data has yet been submitted to ODEP. It should be noted however that some of this usage relates to stems designed for revision surgery being used in primary procedures for unspecified reasons. Revision brands are not covered by NICE guidance
nor the ODEP process. The latest listings for brands currently being used in England and Wales can be seen on the ODEP website:
www.odep.org.uk
Analysis of primary procedures shows that the use of products meeting the full 10 year (10A) benchmark, as recommended by NICE, is as follows:
•Cemented stems 88% (using 14 brands out of 47 recorded on the NJR)
•Cementless stems 69% (17 brands out of 91)
•Cemented cups 34% (10 brands out of 43)
•Cementless cups 3% (7 brands out of 57)
•Resurfacing cups 63% (1 brand out of 9)
These percentages are based on the latest ODEP ratings from clinical outcomes data already submitted to the ODEP committee and published in February 2013. Manufacturers are expected to submit additional data to progress through the ratings and this will result in these percentages changing in the future.
Comparison with the 2011 figures shows that use of cemented and cementless stems achieving the 10-year benchmark has not changed significantly. Usage of cementless stems achieving the 10-year benchmark is 69% (a decrease of 3% on last year). However, the percentage for cementless cups achieving 10-year benchmark was 3%.
2.2.1.5.2 Hip brand usage in primary procedures
Figures 2.9 to 2.13 show historical trends in the usage of the most popular brands of cemented stems, cemented cups, cementless stems, cementless cups and hip resurfacing cups.
Figure 2.9 shows that the market is dominated by polished collarless tapered stems, with the Exeter V40 having a market share of more than 66% and the CPT stem continuing to consolidate its position in second place.
7 See pages 86 to 92 of the 2nd NJR Annual Report, available on the NJR website www.njrcentre.org.uk.
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Figure 2.9 Top five cemented hip stem brands, trends 2003 to 2012.
Figure 2.10 Top five cemented hip cup brands, trends 2003 to 2012.
2004
31,844
2003
18,944Number ofcomponents used
2005
35,608
2006
34,140
2007
35,912
2008
34,004
2009
32,983
2010
33,898
2012
38,406
2011
36,222
Year
0%
70%
60%
50%
40%
30%
20%
10%
Per
cent
age
of p
roce
dur
es
Exeter V40
CPTC-Stem AMTCemented Stem
C-Stem Cemented Stem
Charnley Cemented Stem
2004
25,540
2003
15,318Number ofcomponents used
2005
27,870
2006
25,648
2007
27,051
2008
25,335
2009
24,048
2010
24,276
2012
26,975
2011
25,826
Year
0%
40%
30%
35%
25%
20%
15%
10%
5%Per
cent
age
of p
roce
dur
es
ContemporaryElite PlusOgee
Elite Plus Cemented Cup
MarathonExeter Rim�t
The trend for cemented cups (Figure 2.10) continues to show that sales of different brands are in line with the popularity of the stem manufacturer. The only
significant change being a proportion of Exeter stem users switching from the Contemporary to the Exeter Rimfit cup, both manufactured by Stryker.
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The relative sales of cementless stem brands (Figure 2.11) are very similar to the previous year, with press-fit HA coated stems continuing to dominate the
market. The Corail prosthesis continues to maintain its position as market leader.
Figure 2.11 Top five cementless hip stem brands, trends 2003 to 2012.
2004
10,771
2003
4,462Number ofcomponents used
2005
15,163
2006
18,551
2007
23,698
2008
29,411
2009
32,323
2010
34,921
2012
36,808
2011
35,885
Year
0%
50%
40%
30%
20%
10%
Per
cent
age
of p
roce
dur
es
CorailFurlongHAC Stem
Accolade TaperlocCementless Stem
M/L TaperCementless
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The cementless stem market share has again reflected the sales of the corresponding cementless cups from the same manufacturers, which means that the Pinnacle cup from DePuy has retained its position as the market leader (Figure 2.12) despite appearing to lose some share to other brands, notably the
Exceed ABT from Biomet. More information on the other brands used can be found in the document ‘Prostheses used in hip, knee, ankle, elbow and shoulder replacement procedures 2012’ which can be downloaded from the NJR website.
Figure 2.12 Top five cementless hip cup brands, trends 2003 to 2012.
2004
16,417
2003
7,906Number ofcomponents used
2005
21,186
2006
24,175
2007
28,826
2008
34,367
2009
39,392
2010
44,296
2012
47,656
2011
46,554
Year
0%
40%
30%
35%
25%
15%
20%
5%
10%
Per
cent
age
of p
roce
dur
es
Pinnacle Trident TrilogyExceed ABT CSF Plus
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Figure 2.13 Top five resurfacing head brands, trends 2003 to 2012.
2004
5,031
2003
2,640Number ofcomponents used
2005
6,230
2006
6,502
2007
6,701
2008
5,798
2009
4,358
2010
2,689
2012
1,075
2011
1,883
Year
0%
90%
80%
70%
60%
50%
40%
30%
20%
10%Per
cent
age
of p
roce
dur
es
BHR ResurfacingHead
Adept ResurfacingHead
Cormet 2000Resurfacing Head
Recap ResurfacingHead
AccisResurfacingHead
2.2.1.5.3 Trends in head size use
Figure 2.14 shows the relative usage of different femoral head sizes (for all femoral heads used in conjunction with a femoral stem) each year since the inception of the NJR. It is immediately clear that there has been a gradual increase in the use of larger head sizes (36mm diameter and above). However, between 2010 and 2012 this had been reversed slightly. This trend accurately reflects the trends in usage of LHMoM prostheses during the lifetime of the NJR.
2.2.1.5.4 Trends in hip articulation
Figure 2.15 shows the change in hip articulation types since the inception of the NJR. Only those procedures where complete articulation surfaces can be derived are included. The most interesting observation being the huge rise in the use of ceramic-on-ceramic bearings, from small numbers in 2003 to over 17,000 in 2012, though this has remained steady over the past year. This growth would appear to have been mainly at the expense of metal-on-metal bearings.
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Figure 2.13 shows the sales evolution of brands of hip resurfacing prostheses in the English and Welsh markets. It is evident that the previous trend towards a decline in the usage of the original brands has continued to reverse. The market share of the BHR brand increased significantly during the course of
2012, at the expense of all other brands reflecting its clinical performance when measured against most of its competitors. However, it should be noted that this is against a background of an ongoing decline in the overall volume of resurfacing hip replacement.
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Figure 2.14 Femoral head size, trends 2003 to 2012.
Figure 2.15 Hip articulation, trends 2003 to 2012.
2004
36,137
2003
18,889Number of modularheads components used
2005
45,078
2006
48,497
2007
56,472
2008
61,674
2009
63,875
2010
67,853
2012
74,176
2011
71,247
Year
0%
100%
80%
60%
40%
20%
Per
cent
age
of p
roce
dur
es
22.25mm 26mm 28mm
36mm 38-44mm 46+mm
30mm 32mm 34mm
2004
46,566
2003
25,344Number of procedureswith hip articulationdetails
2005
55,748
2006
58,293
2007
65,629
2008
68,878
2009
69,457
2010
71,450
2011
73,844
2012
75,897
Year
0
45,000
50,000
40,000
35,000
30,000
25,000
20,000
15,000
10,000
5,000
Num
ber
of p
roce
dur
es
Metal-on-poly
Ceramic-on-ceramic
Ceramic-on-poly
Metal-on-metal
Ceramic-on-metal
Metal-on-ceramic*
* This combination is contra-indicated
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2.2.2 Hip revision procedures 2012
A total of 10,040 hip revision procedures were reported in 2012, an increase of 1,401 compared with 2011. Table 2.10 shows that of these, 8,812 (88%) were single-stage revision procedures, 560 (6%) were stage one of a two-stage process, 611 (6%) procedures were stage two of a two-stage revision and 57 (<1%) were excision arthroplasty procedures. Infection as an indication for revision has increased to 12% of the total.
2.2.2.1 Patient characteristics
Table 2.10 summarises patient characteristics for the 10,040 hip revision procedures undertaken in 2012. Compared with 2011, the patient demographics have largely remained unchanged, though there was a slight increase in the average age in each procedure type
(with the exception of excision arthroplasty). However, the percentage of patients who were graded as being fit and healthy prior to surgery has decreased from 26% in 2003 to 10% in 2012.
Aseptic loosening has continued its decrease as a reason for revision compared with previous years. Adverse soft tissue reaction was noted for 13% of all revision procedures (Table 2.10). However, this option was added in July 2009 so it is not possible to tell if this increase is actual or due to a delay in the usage of the new MDS H2 data forms. More than one indication for revision may be given.
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Table 2.10 Patient characteristics for hip revision procedures in 2012, according to procedure type.
Hip single-
stage revision
Hip stage one of two-stage
revision
Hip stage two of two-stage
revision Hip excision arthroplasty
Total revision procedures
No. % No. % No. % No. % No. %
Total revision procedures 8,812 88% 560 6% 611 6% 57 <1% 10,040
Number with patient data 8,475 96% 551 98% 599 98% 51 89% 9,676 96%
Average age 70.0 69.5 68.9 71.3 69.8
SD 12.0 11.3 11.4 13.2 12.0
Interquartile range62.8 -
78.663.0 -
77.663.4 -
77.365.6 -
80.262.9 -
78.4Gender
Female 4,926 58% 269 49% 275 46% 27 53% 5,497 57%
Male 3,549 42% 282 51% 324 54% 24 47% 4,179 43%
Patient physical status
P1 - fit and healthy 894 10% 28 5% 45 7% 2 4% 969 10%P2 - mild disease not incapacitating
5,604 64% 330 59% 362 59% 20 35% 6,316 63%
P3 - incapacitating systemic disease
2,180 25% 186 33% 194 32% 28 49% 2,588 26%
P4 and P5 134 2% 16 3% 10 2% 7 12% 167 2%
Indications for surgery
Aseptic loosening 3,881 44% 62 11% 54 9% 11 19% 4,008 40%
Lysis 1,227 14% 44 8% 32 5% 8 14% 1,311 13%
Pain 2,219 25% 72 13% 51 8% 9 16% 2,351 23%
Dislocation/subluxation 1,207 14% 22 4% 19 3% 9 16% 1,257 13%
Periprosthetic fracture 797 9% 15 3% 27 4% 1 2% 840 8%
Infection 288 3% 455 81% 443 73% 36 63% 1,222 12%
Malalignment 450 5% 6 1% 4 <1% 0 0% 460 5%
Fractured acetabulum 97 1% 3 <1% 0 0% 1 2% 101 1%
Fractured stem 151 2% 4 <1% 3 <1% 0 0% 158 2%
Fractured femoral head 28 <1% 0 0% 0 0% 0 0% 28 <1%
Incorrect sizing head/socket 61 <1% 0 0% 0 0% 1 2% 62 <1%Wear of acetabular component
1,177 13% 12 2% 10 2% 0 0% 1,199 12%
Dissociation of liner 133 2% 7 1% 16 3% 2 4% 158 2%
Adverse soft tissue reaction 1,286 15% 25 4% 19 3% 0 0% 1,330 13%
Other 819 9% 19 3% 57 9% 4 7% 899 9%
Side
Bilateral 4 <1% 0 0% 0 0% 0 0% 4 <1%
Left, unilateral 4,078 46% 285 51% 303 50% 26 46% 4,692 47%
Right, unilateral 4,730 54% 275 49% 308 50% 31 54% 5,344 53%
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2.2.2.2 Components removed and components used
Both the acetabular and femoral components were removed in approximately half of all revision procedures (Table 2.12). However, comparison of the different types of revision procedures indicates that both
components were more likely to be removed during a two-stage revision process than during a single-stage revision. This is expected since the majority of two-stage revisions are carried out for reasons of infection, where all components are routinely removed. The components used during single-stage revision procedures are shown in Table 2.13.
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Table 2.11 Indication for surgery for hip revision procedures 2008 to 2012.
2008 2009 2010 2011 2012 Total
No. % No. % No. % No. % No. % No. %Indications for single-stage revisionNumber of procedures 6,421 17% 6,610 18% 7,375 20% 8,201 22% 8,812 24%
37,419
Aseptic loosening 3,809 59% 3,654 55% 3,700 50% 3,776 46% 3,881 44% 18,820 50%
Pain 1,746 27% 2,032 31% 2,000 27% 2,114 26% 2,219 25% 10,111 27%
Lysis 1,108 17% 997 15% 1,104 15% 1,112 14% 1,227 14% 5,548 15%Adverse soft tissue reaction to particle debris
1 <1% 86 1% 410 6% 982 12% 1,286 15% 2,765 7%
Infection 173 3% 192 3% 236 3% 264 3% 288 3% 1,153 3%
Indications for stage one of a two-stage revisionNumber of procedures 456 17% 554 21% 529 20% 549 21% 560 21% 2,648 Infection 366 80% 440 79% 422 80% 448 82% 455 81% 2,131 80%
Pain 87 19% 103 19% 110 21% 78 14% 72 13% 450 17%
Aseptic loosening 89 20% 84 15% 72 14% 56 10% 62 11% 363 14%
Lysis 58 13% 50 9% 52 10% 43 8% 44 8% 247 9%
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Table 2.12 Components removed during hip revision procedures in 2012.
Hip single-stage
revision Hip stage one of a two-stage revision
Hip excision arthroplasty Total
No. % No. % No. % No. %
Total 8,812 560 57 9,429
Both cup and stem 3,986 45% 470 84% 40 70% 4,496 48%Acetabular cup only 2,662 30% 23 4% 3 5% 2,688 29%
Femoral stem only 1,275 14% 31 6% 10 18% 1,316 14%Neither cup nor stem 889 10% 36 6% 4 7% 929 10%
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Table 2.13 Components used during single-stage hip revision procedures in 2012.
Hip single-stage revision
Number of procedures %
Total 8,812
Femoral prosthesis
Cemented 2,482 28%Cementless 2,569 29%
Not revised 3,761 43%
Acetabular prosthesis
Cemented 1,569 18%Cementless 5,090 58%
Not revised 2,153 24%
2.3 Knee replacement procedures 2012
Part 2
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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The total number of knee replacement procedures entered into the NJR during 2012 was 90,842, an increase of 7.3% compared with 2011. Of the 90,842 procedures submitted, 84,833 were primary procedures and 6,009 were revision procedures. Table 2.14 summarises the patient characteristics and details of knee replacement procedures according to type of provider.
As a percentage of their activity, ISTCs performed more unicondylar knee replacement procedures (Figure 2.16) than any other type of provider and NHS hospitals performed more cemented bicondylar knee procedures than any other provider. The revision procedures undertaken at NHS hospitals comprised 85% of all revision procedures performed.
8 Bilaterals will only be counted as a bilateral if they are entered under the same single operation during data entry. If the two procedures are recorded under two different operations they will be counted as two unilateral procedures. Therefore, the count of bilaterals is likely to be an underestimate.
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Table 2.14 Procedure details, according to type of provider for knee procedures in 2012.
NHS hospitalsIndependent
hospitals ISTC TotalNo. % No. % No. % No. %
Total knee procedures 63,679 70% 23,501 26% 3,662 4% 90,842
Patient physical status
P1 - fit and healthy 5,320 8% 3,873 16% 369 10% 9,562 11%P2 - mild disease not incapacitating
45,825 72% 17,784 76% 3,015 82% 66,624 73%
P3 - incapacitating systemic disease
12,217 19% 1,829 8% 276 8% 14,322 16%
P4 and P5 317 <1% 15 <1% 2 <1% 334 <1%
Procedure type
Primary procedures 58,556 69% 22,749 27% 3,528 4% 84,833 93%Total prosthetic replacement using cement
51,703 88% 18,597 82% 3,040 86% 73,340 86%
Total prosthetic replacement not using cement
1,823 3% 887 4% 1 <1% 2,711 3%
Hybrid total knee 335 <1% 103 <1% 8 <1% 446 <1%
Patello-femoral replacement 815 1% 420 2% 36 1% 1,271 1%
Unicondylar knee replacement 3,880 7% 2,742 12% 443 13% 7,065 8%
Revision procedures 5,123 85% 752 13% 134 2% 6,009 7%
Knee single-stage revision 3,900 76% 657 87% 118 88% 4,675 78%Knee stage one of two-stage revision
548 11% 42 6% 11 8% 601 10%
Knee stage two of two-stage revision
649 13% 52 7% 5 4% 706 12%
Knee conversion to arthrodesis 20 <1% 1 <1% 0 0% 21 <1%
Amputation 6 <1% 0 0% 0 0% 6 <1%
Bilateral or unilateral8
Bilateral 668 1% 374 2% 46 1% 1,088 1%
Unilateral 63,011 99% 23,127 98% 3,616 99% 89,754 99%
Funding
Independent 511 <1% 8,995 38% 16 <1% 9,522 10%
NHS 63,168 99% 14,506 62% 3,646 100% 81,320 90%
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Figure 2.16 Primary knee procedures by type of provider 2012.
0%
20%
40%
60%
80%
100%
Type of provider
Per
cent
age
of p
roce
dur
e ty
pe
Cemented
Cementless
Hybrid
Unicondylar
Patello-femoral
88%
3%
<1%
7%
1%
58,556
NHS hospitals
82%
4%
<1%
12%
2%
22,749
Independenthospitals
86%
<1%
<1%
13%
1%
3,528
ISTCs
Number of procedures
2.3.1 Primary knee replacement procedures 2012
Of the 84,883 primary knee replacements undertaken in 2012, 76,497 (90%) were bicondylar procedures (TKR), 7,065 (8%) were unicondylar knee replacements and 1,271 (1%) were patello-femoral replacements (Table 2.15). Compared with previous years, these proportions have largely remained the same (Figure 2.17) though there has been a slight increase in cemented TKR at the expense of cementless TKR over the past four years. Figure 2.18 is based on total condylar knee
replacements where the meniscal implant has been specified. The usage of unconstrained fixed implants has increased gradually over the past six years at the expense of unconstrained mobile constructs. Figure 2.19 shows that the usage of fixed constraint implants has increased since 2006.
The single largest indication recorded for surgery was osteoarthritis, recorded in 98% of all primary procedures (Table 2.15). All other indications were recorded at 1% or less.
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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Table 2.15 Patient characteristics for primary knee replacement procedures in 2012, according to procedure type.
Primary total
prosthetic replacement
using cement
Primary total prosthetic
replacement not using
cement
Primary total prosthetic
replacement not classified
elsewhere (e.g. hybrid)
Patello-femoral
replacementUnicondylar replacement Total
No. % No. % No. % No. % No. % No. %
Total knee primaries 73,340 86% 2,711 3% 446 <1% 1,271 1% 7,065 8% 84,833
Patient physical status
P1 - fit and healthy 6,881 9% 280 10% 46 10% 309 24% 1,574 22% 9,090 11%P2 - mild disease not incapacitating
54,368 74% 2,092 77% 324 73% 864 68% 4,947 70% 62,595 74%
P3 - incapacitating systemic disease
11,840 16% 333 12% 74 17% 97 8% 536 8% 12,880 15%
P4 and P5 251 <1% 6 <1% 2 <1% 1 <1% 8 <1% 268 <1%
BMINumber with BMI data
51,084 70% 1,577 58% 306 69% 865 68% 5,282 75% 59,114 70%
Average 30.92 31.02 31.25 30.02 30.00 30.83
SD 5.54 5.13 5.35 5.17 4.81 5.47
Indications for surgery
Osteoarthritis 71,384 97% 2,683 99% 428 96% 1,238 97% 6,987 99% 82,720 98%
Avascular necrosis 223 <1% 3 <1% 3 <1% 3 <1% 55 <1% 287 <1%Inflammatory arthropathy
500 <1% 11 <1% 2 <1% 2 <1% 4 <1% 519 <1%
Previous infection 64 <1% 2 <1% 0 0% 0 0% 1 <1% 67 <1%
Rheumatoid arthritis 1,108 2% 15 <1% 4 <1% 1 <1% 5 <1% 1,133 1%
Previous trauma 413 <1% 9 <1% 8 2% 5 <1% 25 <1% 460 <1%
Other 507 <1% 9 <1% 9 2% 32 3% 45 <1% 602 <1%
Side
Bilateral 667 <1% 24 <1% 7 2% 90 7% 292 4% 1,080 1%
Left, unilateral 34,293 47% 1,269 47% 203 46% 504 40% 3,373 48% 39,642 47%
Right, unilateral 38,380 52% 1,418 52% 236 53% 677 53% 3,400 48% 44,111 52%
88 www.njrcentre.org.uk
Figure 2.17 Type of primary knee replacement procedures undertaken between 2006 and 2012.
0%
20%
40%
60%
80%
100%
Year
Per
cent
age
of p
roce
dur
es
TKR using cement
TKR not usingcement
TKR Hybrid
Patello-femoral
UnicondylarNumber of procedures
83%
7%
1%
1%
8%
62,430
2006
83%
6%
1%
1%
8%
73,767
2007
83%
6%
1%
1%
8%
77,754
2008
83%
6%
1%
1%
8%
79,071
2009
85%
5%
<1%
1%
8%
81,427
2010
86%
4%
<1%
1%
8%
84,230
2011
86%
3%
<1%
1%
8%
84,833
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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Figure 2.18 Implant constraint for bicondylar primary knee replacement procedures between 2006 and 2012.
0%
20%
40%
60%
80%
Year
Per
cent
age
of p
roce
dur
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Constrainedcondylar
Posteriorstabilised, �xed
Posteriorstabilised, mobile
Unconstrained,�xed
Unconstrained,mobile
Hinged/linked
Number of procedures
<1%
24%
2%
62%
11%
<1%
54,968
<1%
24%
2%
63%
11%
<1%
64,884
<1%
24%
2%
64%
10%
<1%
68,502
<1%
25%
2%
65%
8%
<1%
69,852
<1%
25%
2%
66%
7%
<1%
71,956
<1%
25%
1%
67%
6%
<1%
74,787
<1%
23%
1%
70%
5%
<1%
76,140
2006 2007 2008 2009 2010 2011 2012
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90 www.njrcentre.org.uk
Figure 2.19 Bearing type for unicondylar implant used in primary knee replacement procedures undertaken between 2006 and 2012.
0%
10%
20%
30%
40%
50%
60%
70%
80%
Year
Per
cent
age
of p
roce
dur
es
Fixed
Mobile
Number of procedures*
25%
75%
5,723
23%
77%
6,639
24%
76%
7,017
26%
74%
7,105
30%
70%
7,460
31%
69%
7,260
36%
64%
7,095
2006 2007 2008 2009 2010 2011 2012
* This is the number of procedures using a unicondylar meniscal implant regardless of patient procedure selected
2.3.1.1 Patient characteristics
According to the ASA grade system, 11% of patients undergoing a primary knee replacement procedure were graded as fit and healthy (Table 2.15).
The average age of patients was 69.3 years and 57% were female. Patients undergoing a patello-femoral replacement were the youngest, at an average age of 59.7 years and 73% of these were female (Table 2.16). On average, female patients were of a similar age to male patients at the time of their primary knee replacement (69.5 years and 68.9 years respectively), see Table 2.16. However, female patients were, on average, older than male patients for cementless, cemented and hybrid procedures but younger for patello-femoral and unicondylar procedures.
Figure 2.21 shows the trend in ASA grade over the past ten years. Since 2003, similar to the data trend for total hip replacement, there has been a reduction in the
number of patients assessed as being fit and healthy at the time of operation and an increase in P2 and P3 status of patients. Figure 2.22 shows the increase in BMI9 over the past nine years for patients having primary knee procedures. This figure has progressively increased from 29.2 to 30.8 over the period. There has been a slight decrease in BMI for female patients whereas the BMI of male patients has continued to increase. It also shows that there has been a steady increase in the number of patients within the BMI range 30 to 34 and 35 to 39 and a decrease within the ranges 20 to 24 and 25 to 29. The average knee replacement patient in 2012, by BMI measurement, was clinically obese. It is interesting to note that the profile of Figure 2.22 is significantly different to the equivalent chart for hips, Figure 2.7.
However, only 16% of entries in 2004 had BMI data entered and while this has increased to 70% in 2012 all BMI data has to be viewed with caution as surgeons may be more likely to enter BMI data when the BMI is high, introducing an element of bias.
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9 BMI: 20-24 normal, 25-29 overweight, 30-39 obese, 40+ morbidly obese.
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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Table 2.16 Age and gender for primary knee replacement patients in 2012.
Primary total
prosthetic replacement
using cement
Primary total prosthetic
replacement not using
cement
Primary total prosthetic
replacement not classified
elsewhere (e.g. hybrid)
Patello-femoral
replacementUnicondylar replacement Total
No. % No. % No. % No. % No. % No. %
Total knee primaries 73,340 86% 2,711 3% 446 <1% 1,271 1% 7,065 8% 84,833 Total knee primaries with patient data
71,022 97% 2,674 99% 429 96% 1,207 95% 6,659 94% 81,991 97%
Average Age 70.01 68.51 68.24 59.74 63.59 69.30
SD 9.36 9.51 10.57 11.74 9.92 9.68
Interquartile Range 63.9 -
76.862.0 -
75.661.1 -
75.951.3 -
67.856.5 -
70.263.0 -
76.3 Average age by gender
Female 41,007 58% 1,318 49% 215 50% 888 74% 3,064 46% 46,492 57%
Average age 70.26 68.91 68.60 59.05 62.95 69.50
SD 9.49 9.66 11.34 11.60 10.13 9.87
Interquartile range64.0 -
77.262.1 -
76.360.0 -
76.750.6 -
67.155.6 -
70.063.0 -
76.7 Male 30,015 42% 1,356 51% 214 50% 319 26% 3,595 54% 35,499 43%
Average age 69.69 68.15 67.98 61.64 64.16 68.90
SD 9.18 9.35 9.80 11.98 9.72 9.45
Interquartile range63.8 -
76.261.9 -
75.161.9 -
74.953.7 -
69.357.3 -
70.063.0 -
75.7Age group by gender
Female
<30 years 16 <1% 1 <1% 0 0% 2 <1% 3 <1% 22 <1 %
30 - 39 years 60 <1% 1 <1% 1 <1% 27 3% 15 <1% 104 <1 %
40 - 49 years 805 2% 38 3% 11 5% 170 19% 307 10% 1,331 3%
50 - 59 years 5,025 12% 192 15% 39 18% 296 33% 887 29% 6,439 14%
60 - 69 years 13,503 33% 464 35% 66 31% 226 25% 1,083 35% 15,342 33%
70 - 79 years 15,145 37% 455 35% 61 28% 127 14% 622 20% 16,410 35%
80 - 89 years 6,187 15% 163 12% 33 15% 40 5% 146 5% 6,569 14%
90+ 266 <1% 4 <1% 4 2% 0 0% 1 <1% 275 <1%
Male
<30 years 6 <1% 0 0% 0 0% 2 <1% 0 0% 8 <1%
30 - 39 years 36 <1% 1 <1% 2 <1% 6 2% 16 <1% 61 <1%
40 - 49 years 653 2% 44 3% 6 3% 43 13% 248 7% 994 3%
50 - 59 years 3,665 12% 209 15% 28 13% 98 31% 922 26% 4,922 14%
60 - 69 years 10,756 36% 508 37% 91 43% 94 29% 1,449 40% 12,898 36%
70 - 79 years 11,023 37% 456 34% 63 29% 54 17% 767 21% 12,363 35%
80 - 89 years 3,737 12% 136 10% 24 11% 19 6% 187 5% 4,103 12%
90+ 139 <1% 2 <1% 0 0% 3 <1% 6 <1% 150 <1%
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Figure 2.20 Age and gender for primary knee replacement patients in 2012.
Patello-femoral
TKR hybrid
TKR not usingcement
TKR using cement
Female
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
roce
dur
es
Age group
Unicondylar9%
0%
5%
73%<30
14%
22
30-39
26%
<1%
<1%
58%
14%
104
40-49
13%
<1%
3%
60%
23%
1,331
50-59
5%
<1%
3%
78%
14%
6,439
60-69
1%
<1%
3%
88%
7%
15,342
70-79
<1%
<1%
3%
92%
4%
16,410
80-89
<1%
1%
2%
94%
2%
6,569
90+
0%
1%
1%
97%
<1%
275Number of patients
Male
Patello-femoral
TKR hybrid
TKR not usingcement
TKR using cement
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
roce
dur
es
Age group
Unicondylar25%
0%
0%
75%<30
0%
8
30-39
10%
3%
2%
59%
26%
61
40-49
4%
<1%
4%
66%
25%
994
50-59
2%
<1%
4%
74%
19%
4,922
60-69
<1%
<1%
4%
83%
11%
12,898
70-79
<1%
<1%
4%
89%
6%
12,363
80-89
<1%
<1%
3%
91%
5%
4,103
90+
2%
0%
1%
93%
4%
150Number of patients
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Figure 2.21 ASA grades for primary knee replacement patients between 2003 and 2012.
0%
20%
40%
60%
80%
100%
Per
cent
age
of p
roce
dur
es
P4 and P5P3P2P1
<1%10%58%
2003
31%
24,665
<1%13%62%
2004
25%
46,596
<1%14%65%
2005
20%
60,767
<1%14%68%
2006
17%
62,430
<1%14%71%
2007
15%
73,767
<1%13%73%
2008
13%
77,754
<1%15%72%
2009
13%
79,071
<1%15%73%
2010
12%
81,427
<1%15%74%
2012
11%
84,833
<1%15%73%
2011
11%
84,230Number ofprocedures
Year
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94 www.njrcentre.org.uk
Figure 2.22 BMI for primary knee replacement patients between 2004 and 2012.
25
32
30
31
29
28
27
26
BM
I
Per
cent
age
of p
atie
nts
0%
35%
30%
20%
25%
50%
40%
45%
10%
5%
15%
Percentage of prwith BMI
with BMI
ocedures
Number of procedures
Year
BMI 30-34
BMI 15-19
BMI 20-24
BMI 25-29
Average BMI- all patients
BMI 35-39
BMI 40-44
BMI 45+
Average BMI- female
Average BMI- male
2004
29.25
1%
17%
38%
28%
11%
3%
1%
30.01
28.77
16%
5,509
2005
29.45
1%
14%
40%
29%
12%
3%
1%
29.96
28.91
15%
9,101
2006
29.53
1%
15%
38%
29%
11%
3%
1%
29.97
28.96
17%
10,579
2007
29.85
<1%
14%
37%
30%
13%
4%
1%
30.32
29.25
22%
16,110
2008
30.28
<1%
12%
36%
31%
14%
4%
1%
30.73
29.69
49%
38,207
2009
30.54
<1%
11%
36%
32%
15%
5%
2%
31.04
29.88
57%
45,200
2010
30.66
<1%
10%
35%
32%
15%
5%
2%
31.16
30.03
61%
49,930
2011
30.81
<1%
10%
35%
32%
16%
5%
2%
31.34
30.14
66%
55,409
2012
30.83
<1%
10%
34%
33%
16%
5%
2%
31.29
30.23
70%
59,114
2.3.1.2 Surgical techniques
The most common surgical approach was the medial parapatellar, used in 93% of procedures (Table 2.17). Minimally-invasive surgery (MIS) was used in 46% of unicondylar knee replacement procedures, reflecting the popularity of the Oxford Partial Knee, but was used in only 2% of all other types of knee replacement intervention. For cemented knee procedures, 38% had the patella replaced at the time of the primary procedure whereas only 7% of patellas were replaced during primary cementless knee procedures.
Compared with previous years, the surgical techniques used in primary knee replacements have largely remained unchanged. However, there has been an increase in the use of MIS in unicondylar knee replacements, from 37% in 2004 to 46% in 2012.
The use of bone cement in primary knee procedures is summarised in Figure 2.23.
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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Table 2.17 Characteristics of surgical practice for primary knee replacement procedures in 2012, according to procedure type.
Primary total
prosthetic replacement
using cement
Primary total prosthetic
replacement not using
cement
Primary total prosthetic
replacement not classified
elsewhere (e.g. hybrid)
Patello-femoral replacement
Unicondylar replacement Total
No. % No. % No. % No. % No. % No. %Total knee primaries
73,340 86% 2,711 3% 446 <1% 1,271 1% 7,065 8% 84,833
Surgical approachLateral parapatellar
590 <1% 20 <1% 8 2% 14 1% 242 3% 874 1%
Medial parapatellar
68,359 93% 2,583 95% 352 79% 1,178 93% 6,193 88% 78,665 93%
Mid-Vastus 2,317 3% 54 2% 19 4% 35 3% 268 4% 2,693 3%
Sub-Vastus 1,281 2% 10 <1% 64 14% 22 2% 209 3% 1,586 2%
Other 793 1% 44 2% 3 <1% 22 2% 153 2% 1,015 1%
PatellaPatella implanted
27,819 38% 190 7% 123 28% 1,231 97% 60 1% 29,423 35%
Patella not implanted
45,521 62% 2,521 93% 323 72% 40 3% 7,005 99% 55,410 65%
Minimally-invasive surgery
Yes 1,750 2% 99 4% 7 2% 158 12% 3,222 46% 5,236 6%
No 71,590 98% 2,612 96% 439 98% 1,113 88% 3,843 54% 79,597 94%
Image-guided surgery
Yes 2,169 3% 206 8% 25 6% 3 <1% 67 1% 2,470 3%
No 71,171 97% 2,505 92% 421 94% 1,268 100% 6,998 99% 82,363 97%
Bone graft used - femur
Yes 521 <1% 15 <1% 3 <1% 0 0% 22 <1% 561 <1%
No 72,819 99% 2,696 99% 443 99% 1,271 100% 7,043 100% 84,272 99%
Bone graft used - tibia
Yes 267 <1% 12 <1% 4 <1% 1 <1% 7 <1% 291 <1%
No 73,073 100% 2,699 100% 442 99% 1,270 100% 7,058 100% 84,542 100%
96 www.njrcentre.org.uk
Figure 2.23 Bone cement types for primary knee replacement procedures undertaken between 2003 and 2012.
Number of procedures
0%
50%
40%
30%
20%
10%
60%
70%
80%
90%
Year
Per
cent
age
of p
roce
dur
es
Antibiotic-loadedhigh viscosity
Antibiotic-loadedmedium viscosity
Antibiotic-loadedlow viscosity
High viscosity
Medium viscosity
Low viscosity
36,472
84%
2004
3%
3%
7%
4%
<1%
18,396
82%
2003
3%
2%
6%
6%
<1%
50,062
86%
2005
3%
3%
4%
3%
<1%
52,656
87%
2006
2%
2%
5%
4%
<1%
64,584
89%
2007
3%
1%
4%
3%
<1%
69,710
91%
2008
2%
<1%
4%
2%
<1%
75,702
91%
2010
3%
<1%
3%
2%
<1%
80,164
95%
2012
3%
<1%
<1%
1%
0%
78,929
94%
2011
2%
<1%
2%
2%
<1%
71,979
91%
2%
<1%
4%
3%
<1%
2009
using cement
2.3.1.3 Thromboprophylaxis
Table 2.18 shows that the most frequently prescribed chemical method of thromboprophylaxis for knee replacement patients was LMWH (72%), while TED stockings were the most used mechanical method (70%). Compared with previous years, there has been an increase in the prescription of a combined chemical and mechanical regime, from 49% in 2004
to 92% in 2012. There has been a marked decrease over the past two years in the use of aspirin (from 20% in 2009 to 8% in 2012). Direct thrombin inhibitor is now used in 13% of knee primary procedures and the use of ‘other chemical’ has gone up from 7% in 2009 to 12% in 2012. This change was also seen in hip primary procedures. Less than 1% of patients had neither mechanical nor chemical-prescribed thromboprophylaxis.
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2.3.1.4 Untoward intra-operative events
Table 2.19 shows that untoward intra-operative events were rare, reported in less than 1% of knee procedures. There were fewer instances reported in 2012 compared to 2011.
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Table 2.18 Thromboprophylaxis regime for primary knee replacement patients, prescribed at time of operation.
Total
No. %
Totals 84,833
Aspirin 6,568 8%
Low molecular weight Heparin 61,347 72%
Pentasaccharide 1,265 1%
Warfarin 559 <1%
Direct thrombin inhibitor 10,731 13%
Other chemical (all) 10,039 12%
No chemical 3,118 4%
Foot pump 22,482 27%
Intermittent calf compression 36,027 42%
TED stockings 59,351 70%
Other 1,177 1%
No mechanical 3,867 5%
Both mechanical and chemical 77,926 92%
Neither mechanical nor chemical 47 <1%
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2.3.1.5 Knee primary components
Figure 2.24 shows the leading brands of total condylar knees in England and Wales. The PFC Sigma knee,
marketed by DePuy, continues to dominate the market. The Triathlon, Genesis 2 and Vanguard appear to be increasing in popularity.
Figure 2.24 Top five total condylar knee brands, trends 2003 to 2012.
2004
40,866
2003
21,627Number ofcomponents used
2005
53,573
2006
54,849
2007
64,841
2008
68,348
2009
69,467
2010
71,543
2012
75,961
2011
74,544
Year
0%
40%
30%
20%
10%
Per
cent
age
of p
roce
dur
es
PFC Sigma Bicondylar Knee Nexgen Triathlon Genesis 2 Vanguard
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Table 2.19 Reported untoward intra-operative events for primary knee replacement patients in 2012, according to procedure type.
Primary total
prosthetic replacement
using cement
Primary total prosthetic
replacement not using
cement
Primary total prosthetic
replacement not classified
elsewhere (e.g. hybrid)
Patello-femoral
replacementUnicondylar replacement Total
No. No. No. No. No. No.
Total knee primaries 73,340 2,711 446 1,271 7,065 84,833 Number of procedures with no events specified
72,829 2,703 442 1,263 7,041 84,278
Total specified 511 8 4 8 24 555
Fracture 128 1 2 2 10 143
Patella tendon avulsion 26 0 0 0 3 29
Ligament injury 60 0 0 0 3 63
Other 297 7 2 6 8 320
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The brand usage for patello-femoral prostheses are shown in Figure 2.26 and the equivalent graph for
highly constrained and hinged revision knees is shown in Figure 2.27.
Likewise, the market for unicondylar knees is dominated by one product, the Oxford Partial Knee (Figure 2.25). The market share of the Oxford Partial has decreased gradually since 2003 and the Sigma HP, still relatively new to the market, and the Zimmer Uni continue to be the next most used brands of unicondylar knee system.
More information on the other brands used can be found in the document ‘Prostheses used in hip, knee, ankle, elbow and shoulder replacement procedures 2012’ which can be downloaded from the NJR website.
Figure 2.25 Top five unicondylar knee brands, trends 2003 to 2012.
2004
4,261
2003
2,226Number ofcomponents used
2005
5,439
2006
5,750
2007
6,659
2008
7,083
2009
7,181
2010
7,458
2012
7,078
2011
7,269
Year
0%
60%
70%
80%
50%
40%
30%
20%
10%Per
cent
age
of p
roce
dur
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Oxford Partial Knee AMC/UniglideSigma HP Triathlon UniZimmer Uni
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Figure 2.26 Top five patello-femoral knee brands, trends 2003 to 2012.
2004
503
2003
267Number ofcomponents used
2005
673
2006
728
2007
1,017
2008
1,155
2009
1,200
2010
1,255
2012
1,210
2011
1,320
Year
0%
60%
70%
80%
50%
40%
30%
20%
10%Per
cent
age
of p
roce
dur
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Avon Sigma HP Journey PFJ OxiniumZimmer PFJ FPV
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Figure 2.27 Top five fixed hinged knee brands, trends 2003 to 2012.
2004
129
2003
70Number ofcomponents used
2005
195
2006
213
2007
262
2008
282
2009
307
2010
305
2012
294
2011
306
Year
0%
60%
50%
40%
30%
20%
10%
Per
cent
age
of p
roce
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Endo RotatingHinge
MRHNexgen HingeType
RT-Plus Noiles
2.3.2 Knee revision procedures 2012
A total of 6,009 knee revision procedures were reported, an increase of 17% on 2011. Of these, 4,675 (78%) were single-stage revision procedures, 601 (10%) were stage one of a two-stage revision
and 706 (12%) were stage two of a two-stage revision (Table 2.20). A further 27 procedures were recorded, comprising 21 conversions of previous knee replacements to arthrodesis and six knee amputations. Compared with previous years, there has been no change in the types of revision procedures carried out.
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2.3.2.1 Patient characteristics
The mean age of knee revision patients was 69 years (Table 2.20). The average has decreased by 0.5 years compared with 2011. There were more female (52%) than male patients (48%) which is similar to 2011. Aseptic loosening was the most common indication for
single-stage revision (38%) and infection was the most common indication for two-stage revision, conversion to arthrodesis and amputation.
Compared with previous years, the patient characteristics described above have largely remained the same.
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Table 2.20 Patient characteristics for knee revision procedures in 2012, according to procedure type.
Knee single-
stage revision
Knee stage one of two-stage
revision
Knee stage two of two-
stage revision
Knee conversion to
arthrodesisKnee
Amputation Total
No. % No. % No. % No. % No. % No. %
Total 4,675 78% 601 10% 706 12% 21 <1% 6 <1% 6,009
Total with patient data 4,546 97% 583 97% 687 97% 19 90% 6 100% 5,841 97%
Average age 68.76 69.74 69.87 71.71 70.62 68.97
SD 10.47 10.28 9.49 9.80 12.25 10.64
Interquartile range61.77 -
76.3363.41 -
77.2063.60 -
77.1267.55 -
76.9668.53 -
78.4562 .09 -
76.48
Gender
Female 2,466 54% 242 42% 295 43% 10 53% 5 83% 3,018 52%
Male 2,080 46% 341 58% 392 57% 9 47% 1 17% 2,823 48%
Patient physical status
P1 - fit and healthy 408 9% 31 5% 33 5% 0 0% 0 0% 472 8%
P2 - mild disease not incapacitating 3,217 69% 366 61% 434 61% 10 48% 2 33% 4,029 67%
P3 - incapacitating systemic disease 1,005 21% 192 32% 230 33% 11 52% 4 67% 1,442 24%
P4 and P5 45 1% 12 2% 9 1% 0 0% 0 0% 66 1%
Indications for surgery
Aseptic loosening 1,778 38% 69 11% 84 12% 1 5% 0 0% 1,932 32%
Pain 846 18% 27 4% 31 4% 2 10% 0 0% 906 15%
Lysis 405 9% 59 10% 40 6% 1 5% 0 0% 505 8%
Wear of polyethylene component 563 12% 14 2% 14 2% 0 0% 0 0% 591 10%
Instability 792 17% 24 4% 31 4% 2 10% 0 0% 849 14%
Infection 255 5% 512 85% 541 77% 14 67% 4 67% 1,326 22%
Malalignment 368 8% 7 1% 9 1% 0 0% 0 0% 384 6%
Stiffness 297 6% 12 2% 9 1% 2 10% 0 0% 320 5%
Progressive arthritis remaining 540 12% 3 <1% 10 1% 0 0% 0 0% 553 9%
Dislocation/subluxation 188 4% 5 <1% 14 2% 0 0% 0 0% 207 3%
Periprosthetic fracture 187 4% 8 1% 4 <1% 1 5% 0 0% 200 3%
Component dissociation 86 2% 2 <1% 4 <1% 0 0% 0 0% 92 2%
Implant fracture 49 1% 2 <1% 2 <1% 0 0% 0 0% 53 <1%
Other 493 11% 24 4% 54 8% 2 10% 4 67% 577 10%
Side
Bilateral 8 <1% 0 0% 0 0% 0 0% 0 0% 8 <1%
Left, unilateral 2,168 46% 299 50% 347 49% 13 62% 2 33% 2,829 47%
Right, unilateral 2,499 53% 302 50% 359 51% 8 38% 4 67% 3,172 53%
Part 22.4 Ankle replacement procedures 2012
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The NJR started recording primary and revision total ankle replacements on 1 April 2010. By reviewing submitted procedures against ankle levy submissions, we have calculated compliance of ankle joint NJR submissions to be 77%, which is improving on previous years but further work is required.
A total of 590 ankle replacement proformas, comprising 540 primary and 50 revision procedures carried out between 1 January and 31 December 2012, were submitted to the NJR by 28 February 2013. Due to the small number collected so far the procedures tables in this section are displayed at a summary level only. Of all the ankle procedures carried out 86% were funded by the NHS. 84% of patients were classified as P1 – fit and healthy (15%) or P2 – had mild disease not incapacitating (69%). (Table 2.21)
2.4.1 Primary ankle replacement procedures 2012
Of the 540 primary procedures, 414 (77%) were performed in the NHS, 107 (20%) in the independent sector and 19 (3%) in ISTCs. Almost all of the primary
procedures performed were reported as being uncemented but the use of cement was reported in five cases, three of which pertained to a hybrid procedure.
2.4.1.1 Patient characteristics
The average age of female patients was 64.7 years whereas the average age for a male patient was 68.8 years. 58% of patients were male (Table 2.22). The BMI average was 29.0, which is higher than for hip primary procedures but lower than knee primary procedures. No bilateral procedures were submitted to the NJR and 55% of procedures were performed on the right ankle. 84% of patients had their procedure performed due to osteoarthritis and 13% due to inflammatory arthritis. The pre-operative range of movement and degrees of deformity can be seen in Table 2.21.
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Table 2.21 Patient characteristics for primary ankle replacement procedures in 2012.
Primary proceduresNo. %
Total ankle primaries 540
Patient physical status
P1 - fit and healthy 81 15%
P2 - mild disease not incapacitating 371 69%
P3 - incapacitating systemic disease 87 16%
P4 and P5 1 <1%
Indications for surgery
Osteoarthritis 455 84%
Rheumatoid arthritis 56 10%
Other inflammatory arthropathy 17 3%
Other 20 4%
Tibia-hindfoot alignment
Physiological neutral 247 46%
5-15° Varus 126 23%
16-30° Varus 26 5%
>30° Varus 2 <1%
5-15° Valgus 71 13%
16-30° Valgus 15 3%
>30° Valgus 3 <1%
Not available 50 9%Pre-operative range of movementankle dorsiflexion5-20° 229 42%
Neutral 208 39%
Fixed equinus 54 10%
Not available 49 9%Pre-operative range of movementankle plantarflexion5-15° 292 54%
16-45° 185 34%
Not available 63 12%
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2.4.1.2 Surgical techniques
Table 2.23 details the surgical technique used during ankle primary procedures. Additional ankle related procedures were performed in 36% of procedures.
Achilles tendon lengthening was performed in 11% of procedures and subtalar joint fusion in 6%. Bone graft was used in 15% of procedures.
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Table 2.22 Age and gender for primary ankle replacement patients in 2012.
Primary procedures
No. %
Total ankle primaries 540
Total ankle primaries with patient data 519 96%
Female age 218 42%
Average 64.7
SD 12.1
Interquartile range 57.2 - 73.3
Male age 301 58%
Average 68.8
SD 9.4
Interquartile range 63.5 - 76.1
Female age groups
<45 years 18 8%
45 - 54 years 27 12%
55 - 64 years 51 23%
65 - 74 years 79 36%
75 - 84 years 40 18%
>85 years 3 1%
Male age groups
<45 years 6 2%
45 - 54 years 20 7%
55 - 64 years 64 21%
65 - 74 years 130 43%
75 - 84 years 75 25%
>85 years 6 2%
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Table 2.23 Characteristics of surgical practice for primary ankle replacement procedures in 2012.
Primary procedures
No. %
Total ankle primaries 540
Incision
Anterior 523 97%
Anterolateral 8 1%
Lateral (transfibular) 2 <1%
Other 7 1%
Associated procedures at time of surgery
Subtalar joint fusion 30 6%
Talonavicular fusion 19 4%
Calcaneal displacement osteotomy 17 3%
Achilles tendon lengthening 59 11%
Fusion distal tibiofibular joint 1 <1%
Fibula osteotomy 3 <1%
Medial malleolar osteotomy 4 <1%
Lateral ligament reconstruction 4 <1%
Medial ligament reconstruction 2 <1%
Other 77 14%
None 348 64%
Image-guided surgery
Yes 6 1%
No 534 99%
Bone graft used
Yes 79 15%
No 461 85%
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2.4.1.4 Untoward intra-operative events
In 4% of procedures an untoward intra-operative event was reported. Of those reported the most common
was ‘Fracture of the medial malleolus’ which occurred in 15 primary procedures (3%).
2.4.1.3 Thromboprophylaxis
Table 2.24 shows that 80% of primary ankle replacement procedures used both chemical and mechanical thromboprophylaxis regimes and
only 2% used neither mechanical nor chemical regimes. LMWH was the most popular chemical thromboprophylaxis regime used in 80% of total ankle replacement (TAR) procedures.
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Table 2.24 Thromboprophylaxis regime for primary ankle replacement patients, prescribed at time of operation.
Total
No. %
Total ankle primaries 540
Aspirin 26 5%
Low molecular weight Heparin 430 80%
Pentasaccharide 0 0%
Warfarin 8 1%
Direct thrombin inhibitor 16 3%
Other chemical 62 11%
No chemical 32 6%
Foot pump 70 13%
Intermittent calf compression 154 29%
TED stockings 303 56%
Other mechanical 17 3%
No mechanical 87 16%
Both mechanical and chemical 432 80%
Neither mechanical nor chemical 11 2%
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Table 2.25 Reported untoward intra-operative events for primary ankle replacement patients in 2012.
Total ankle primaries 540
Total events specified 24
Fracture of medial malleolus 15
Fracture of lateral malleolus 2
Fracture (other) 3
Ligament Injury 0
Other 4
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2.4.1.5 Ankle primary components
The DePuy Mobility ankle prosthesis was used in 52% of all primary procedures recorded in 2012. The next most commonly used prosthesis was Corin’s Zenith ankle replacement at 20% followed by MatOrtho’s BOX prosthesis at 8%. More information on the other brands used can be found in the document ‘Prostheses used in hip, knee, ankle, elbow and
shoulder replacement procedures 2012’ which can be downloaded from the NJR website.
2.4.2 Ankle revision procedures 2012
Of the 50 revision procedures, 46 were performed in the NHS (92%). 66% were single-stage revisions and 22% were conversion to arthrodesis.
2.4.2.1 Patient characteristics
The average age for a patient having a revision procedure was 64.7 years. Only 12% were fit and healthy and 24% had severe systemic disease (P3). 36% of revisions were for undiagnosed pain and 20% due to infection – low suspicion.
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Table 2.26 Details for ankle revision procedures in 2012.
Procedure type Patient procedure No.
50
Single-stage revision Prosthetic replacement not classified elsewhere (e.g. hybrid) 4
Single-stage revision Prosthetic replacement not using cement 29
Stage one of two-stage revision 2
Stage two of two-stage revision Prosthetic replacement not classified elsewhere (e.g. hybrid) 1
Stage two of two-stage revision Prosthetic replacement not using cement 2
Stage two of two-stage revision Prosthetic replacement using cement 1
Conversion to arthrodesis Conversion to ankle fusion (subtalar joint not fused) 3
Conversion to arthrodesis Conversion to ankle & subtalar fusion (not using ttc nail) 4
Conversion to arthrodesis Conversion to ankle & subtalar fusion (using ttc nail) 4
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Table 2.27 Patient characteristics for ankle revision procedures in 2012.
Revision procedures
No. %
Total 50
Patient physical status
P1 - fit and healthy 6 12%
P2 - mild disease not incapacitating 32 64%
P3 - incapacitating systemic disease 12 24%
P4 and P5 0 0%
Indications for surgery
Infection high suspicion 3 6%
Infection low suspicion 10 20%
Aseptic loosening - tibial 9 18%
Aseptic loosening - talar 8 16%
Lysis - tibia 4 8%
Lysis - talus 2 4%
Malalignment 9 18%
Implant fracture - tibia 1 2%
Implant fracture - talar 1 2%
Implant fracture - meniscal 5 10%
Wear of polyethylene component 6 12%
Meniscal insert dislocation 0 0%
Component migration/dissociation 2 4%
Pain (undiagnosed) 18 36%
Stiffness 4 8%
Soft tissue impingement 3 6%
Other 6 12%
Side
Bilateral 0 0%
Left, unilateral 21 42%
Right, unilateral 29 58%
2.5 Elbow replacement procedures 2012
Part 2
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The NJR started recording primary and revision elbow replacements on 1 April 2012. This Annual Report therefore deals with nine months of operation data (1 April to 31 December 2012).
A total of 288 elbow replacement procedures, comprising 214 primary and 74 revision procedures carried out between 1 April and 31 December 2012, were submitted to the NJR by 28 February 2013. Due to the small number collected so far the procedures tables in this section are displayed at a summary level only.
2.5.1 Primary elbow replacement procedures 2012 (nine months)
Of the 214 primary procedures, 200 (93%) were performed in the NHS, and the remaining in the
independent sector. 88% of the primary procedures were total elbow replacement procedures and 9% were radial head replacements only (Table 2.28). Primary procedures were mainly performed due to other inflammatory arthropathy (33%) and osteoarthritis (32%).
2.5.1.1 Patient characteristics
The average age of female patients was 66.9 years whereas the average age for a male patient was 65.6 years. 67% of patients were female (Table 2.29). 83% of patients were right handed and 3% were ambidextrous. Table 2.29 shows that 54% have ASA grade of P2 and 34% have P3 – incapacitating systemic disease.
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Table 2.28 Details for primary elbow procedures in 2012 (nine months).
Primary procedures
No. %
Total elbow primaries 214
Procedure type
Primary radial head replacement 20 9%
Primary total prosthetic replacement 188 88%
Primary lateral resurfacing 6 3%
Primary indications
Osteoarthritis 69 32%
Other inflammatory arthropathy 70 33%
Essex Lopresti 0 0%
Avascular necrosis 0 0%
Acute trauma 50 23%
Trauma sequelae 29 14%
Failed hemiarthroplasty 1 <1%
Other 7 3%
Side
Left 119 56%
Right 95 44%
Organisation type
NHS - England 190 89%
NHS - Wales 10 5%
Independent 14 7%
Funding
Independent 12 6%
NHS 202 94%
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Table 2.29 Patient characteristics for primary elbow replacement procedures in 2012 (nine months).
Primary procedures
No. %
Total elbow primaries 214
Patient physical status
P1 - fit and healthy 25 12%
P2 - mild disease not incapacitating 115 54%
P3 - incapacitating systemic disease 73 34%
P4 and P5 1 <1%
Handedness
Ambidextrous 6 3%
Left 31 14%
Right 177 83%
Total elbow primaries with patient data 196 92%
Female age 131 67%
Average 66.9
SD 14.7
Interquartile range 59.6 - 77.4
Male age 65 33%
Average 65.6
SD 13.9
Interquartile range 58.0 - 74.5
Age groups 196
<45 years 18 9%
45 - 54 years 20 10%
55 - 64 years 40 20%
65 - 74 years 61 31%
75 - 84 years 41 21%
>85 years 16 8%
2.5.1.2 Surgical techniques
Table 2.30 details the surgical technique used during elbow primary procedures. 89% of elbow procedures were performed using a posterior approach and less than 1% used image-guided surgery. 16% of replacements required humeral bone grafting but
less than 1% required an ulnar bone graft. 8% of procedures resulted in an untoward intra-operative event with fracture of the humerus occurring in 39% of these and shaft penetration of the ulna in 33%.
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Table 2.30 Characteristics of surgical practice for primary elbow replacement procedures in 2012 (nine months).
Primary procedures
No. %
Total 214
Incision
Kocher 24 11%
Posterior 190 89%
Image-guided surgery
Yes 2 <1%
No 212 99%
Humeral bone graft used
Yes 34 16%
No 180 84%
Ulnar bone graft used
Yes 2 <1%
No 212 99%
Untoward intra-operative events
Procedures with none specified 198
Procedures with events specified 16 7%
No. of events specified 18
Shaft penetration humerus 1 6%
Shaft penetration ulna 6 33%
Fracture humerus 7 39%
Fracture ulna 1 6%
Nerve injury 0 0%
Vascular injury 0 0%
Other 3 17%
2.5.1.3 Thromboprophylaxis
Table 2.31 shows that 90% of elbow replacement procedures used mechanical methods and 66% used chemical methods; 60% of primary procedures used
both chemical and mechanical thromboprophylaxis regimes. 4% used neither mechanical nor chemical regimes. LMWH was the most popular chemical thromboprophylaxis regime used in 59% of procedures.
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Table 2.31 Thromboprophylaxis regime for primary elbow replacement patients, prescribed at time of operation.
Total no. of primary procedures
No. %
Total 214
Aspirin 1 <1%
Low molecular weight Heparin 126 59%
Pentasaccharide 0 0%
Warfarin 1 <1%
Direct thrombin inhibitor 2 <1%
Other chemical 11 5%
No chemical 73 34%
Foot pump 50 23%
Intermittent calf compression 81 38%
TED stockings 116 54%
Other mechanical 3 1%
No mechanical 21 10%
Both mechanical and chemical 129 60%
Neither mechanical nor chemical 9 4%
2.5.2 Elbow revision procedures 2012
Of the 74 revision procedures, 74% were single-stage revisions (Table 2.32). Aseptic loosening accounted for 50% of the reasons for revision.
67% of the patients were female and their average age was 65.3. The average age for male patients undergoing revision was 63.9.
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Table 2.32 Details for elbow revision procedures in 2012 (nine months).
Procedure type Patient procedure No. %
Total 74
Single-stage revision Revision to lateral resurfacing 1 1%
Single-stage revision Revision total prosthetic replacement 54 73%
Stage one of two-stage revision 6 8%
Stage two of two-stage revision Revision total prosthetic replacement 10 14%
Excision arthroplasty 3 4%
Indications for surgery
Aseptic loosening 37 50%
Infection 13 18%
Instability 9 12%
Periprosthetic fracture 14 19%
Other 15 20%
Side
Left 32 43%
Right 42 57%
Total elbow revision procedures with patient data 73 99%
Female age 49 67%
Average 65.3
SD 13.6
Interquartile range 56.6 - 75.4
Male age 24 33%
Average 63.9
SD 13.1
Interquartile range 55.0 - 72.4
2.5.3 Elbow components used in primary and revision procedures
The Zimmer Coonrad Morrey had 45% of the market share in total elbow replacement prostheses used in primary and revision procedures. For procedures
where only the radial head was replaced, the most used brand was the Anatomic Radial head manufactured by Acumed. More information on the other brands used can be found in the document ‘Prostheses used in hip, knee, ankle, elbow and shoulder replacement procedures 2012’ which can be downloaded from the NJR website.
2.6 Shoulder replacement procedures 2012
Part 2
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The NJR started recording primary and revision shoulder replacements on 1 April 2012. This Annual Report therefore deals with nine months of operation data (1 April to 31 December 2012).
A total of 2,225 shoulder replacement procedures, comprising 1,968 primary and 257 revision procedures carried out between 1 April and 31 December 2012, were submitted to the NJR by 28 February 2013. Due to the small number collected so far the procedures tables in this section are displayed at a summary level only.
2.6.1 Primary shoulder replacement procedures 2012 (nine months)
Of the 1,968 primary procedures, 1,630 (83%) were performed in the NHS sector and the remaining in the
independent sector. The most frequently performed primary procedure was the reverse polarity total shoulder replacement at 597 (30%) followed by the standard polarity total shoulder replacement with 525 (27%) procedures (Table 2.33). Primary procedures were mainly performed due to osteoarthritis (61%) and cuff tear arthropathy (24%).
2.6.1.1 Patient characteristics
The average age of female patients was 73.2 years whereas the average age for a male patient was 68.8 years. 72% of patients were female (Table 2.34). 84% of patients were right handed and 4% were ambidextrous. Table 2.34 shows that 62% had ASA grade of P2 and 28% have P3 – incapacitating systemic disease.
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Table 2.33 Details for primary shoulder procedures in 2012 (nine months).
Primary procedures
No. %
Total shoulder primaries 1,968
Procedure type
Primary total prosthetic replacement 525 27%
Primary hemi-arthroplasty of joint 296 15%
Primary resurfacing arthroplasty of joint 122 6%
Primary resurfacing hemi-arthoplasty of joint 428 22%
Primary reverse polarity total prosthetic replacement 597 30%
Primary indications
Osteoarthritis 1,202 61%
Cuff tear arthropathy 470 24%
Other inflammatory arthropathy 112 6%
Avascular necrosis 81 4%
Acute trauma 92 5%
Trauma sequelae 111 6%
Other 54 3%
Side
Left 921 47%
Right 1,047 53%
Organisation type
NHS - England 1,567 80%
NHS - Wales 63 3%
Independent 289 15%
ISTC 49 2%
Funding
Independent 151 8%
NHS 1,817 92%
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Table 2.34 Patient characteristics for primary shoulder replacement procedures in 2012 (nine months).
Primary procedures
No. %
Total shoulder primaries 1,968
Patient physical status
P1 - fit and healthy 173 9%
P2 - mild disease not incapacitating 1,214 62%
P3 - incapacitating systemic disease 558 28%
P4 and P5 23 1%
Previous surgery (not arthroplasty)
None 1,623 82%
Cuff repair 85 4%
Excision ACJ 31 2%
Stabilisation 28 1%
Subacromial decompression 132 7%
Other 134 7%
Handedness
Ambidextrous 69 4%
Left 254 13%
Right 1,645 84%
Total shoulder primaries with patient data 1,894 96%
Female age 1,359 72%
Average 73.2
SD 9.3
Interquartile range 68.1 - 79.8
Male age 535 28%
Average 68.8
SD 11.3
Interquartile range 63.1 - 77.1
Age groups 1,894
<45 years 38 2%
45 - 54 years 93 5%
55 - 64 years 256 14%
65 - 74 years 688 36%
75 - 84 years 698 37%
>85 years 121 6%
2.6.1.2 Surgical techniques
Table 2.35 details the surgical technique used during shoulder primary procedures. 75% of shoulder procedures were performed using a delto-pectoral approach and less than 1% used image-guided surgery. 12% of replacements required humeral bone
graft and 4% required glenoid bone graft. Long head biceps tenotomy was required in 45% of procedures and 43% had normal rotator cuff condition. 2% of procedures resulted in an untoward intra-operative event with vascular injury occurring in 44% of these.
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Table 2.35 Characteristics of surgical practice for primary shoulder replacement procedures in 2012 (nine months).
Primary procedures
No. %
Total 1,968
Approach
Deltoid detachment 11 1%
Deltoid split 112 6%
Delto-pectoral 1,474 75%
Posterior 9 <1%
Superior (MacKenzie) 362 18%
Image-guided surgery
Yes 2 <1%
No 1,966 100%
Humeral bone graft used
Yes 243 12%
No 1,725 88%
Glenoid bone graft used
Yes 79 4%
No 1,889 96%
Soft tissues
Long head biceps tenotomy 882 45%
Rotator cuff condition
Normal 848 43%
Attenuated 470 24%
Absent/torn 590 30%
Repaired 60 3%
Untoward intra-operative events
Procedures with none specified 1,920
Procedures with events specified 48 2%
No. of events specified 48
Shaft penetration 1 2%
Fracture humerus 15 31%
Fracture glenoid 10 21%
Nerve injury 0 0%
Vascular injury 21 44%
Other 1 2%
2.6.1.3 Thromboprophylaxis
Table 2.36 shows that 93% of shoulder replacement procedures used mechanical methods and 65% used chemical methods; 61% of primary procedures used both chemical and mechanical thromboprophylaxis
regimes. 4% used neither mechanical nor chemical regimes. LMWH was the most popular chemical thromboprophylaxis regime used in 57% of procedures and TED stockings, the most popular mechanical thromboprophylaxis, were used in 60% of procedures.
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Table 2.36 Thromboprophylaxis regime for primary shoulder replacement patients, prescribed at time of operation.
Total no. of primary procedures
No. %
Total 1,968
Aspirin 52 3%
Low molecular weight Heparin 1,118 57%
Pentasaccharide 7 <1%
Warfarin 22 1%
Direct thrombin inhibitor 35 2%
Other chemical 71 4%
No chemical 695 35%
Foot pump 376 19%
Intermittent calf compression 802 41%
TED stockings 1,180 60%
Other mechanical 18 <1%
No mechanical 142 7%
Both mechanical and chemical 1,202 61%
Neither mechanical nor chemical 71 4%
2.6.2 Shoulder components used in primary procedures
The Delta Xtend reverse shoulder from DePuy had 22% of the total shoulder replacement market for primary procedures. The Copeland shoulder system from Biomet has 27% of market share for primary resurfacing. More information on the other brands used can be found in the document ‘Prostheses used in hip, knee, ankle, elbow and shoulder replacement procedures 2012’ which can be downloaded from the NJR website.
2.6.3 Shoulder revision procedures 2012 (nine months)
Of the 257 revision procedures, 86% were single-stage revisions (Table 2.37). Conversion from a hemi to a total was the cause for 30% of revision procedures performed. 68% of the patients were female and their average age was 69.9. The average age for male patients undergoing revision was 68.5.
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Table 2.37 Details for shoulder revision procedures in 2012 (nine months).
Procedure type Patient procedure No. %
Total 257
Single-stage revision Revision hemi-arthroplasty of joint 27 11%
Single-stage revision Revision resurfacing arthoplasty of joint 13 5%
Single-stage revisionRevision resurfacing hemi-arthoplasty of joint
9 4%
Single-stage revisionRevision reverse polarity total prosthetic replacement
109 42%
Single-stage revision Revision total prosthetic replacement 63 25%
Stage one of two-stage revision 14 5%
Stage two of two-stage revision Revision hemi-arthroplasty of joint 4 2%
Stage two of two-stage revision Revision resurfacing arthoplasty of joint 1 <1%
Stage two of two-stage revisionRevision reverse polarity total prosthetic replacement
11 4%
Stage two of two-stage revision Revision total prosthetic replacement 6 2%
Indications for surgery
Aseptic loosening 36 14%
Conversion hemi to total 77 30%
Conversion total to hemi 1 <1%
Cuff insufficiency 65 25%
Infection 25 10%
Instability 34 13%
Periprosthetic fracture 11 4%
Other 60 23%
Side
Left 128 50%
Right 129 50%
Total shoulder revision procedures with patient data 241 94%
Female age 164 68%
Average 69.9
SD 9.1
Interquartile range 64.9 - 75.5
Male age 77 32%
Average 68.5
SD 10.3
Interquartile range 62.8 - 75.4
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3.1 Summary of data sources and linkage
Outcomes after joint replacement 2003 to 2012
Part 3
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The outcome analyses have been based on all patients with at least one primary joint replacement carried out between 1 April 2003 and 31 December 2012, inclusive, and whose record had been submitted to the NJR by the end of February 2013.
Documentation of implant survivorship and mortality require a person-level identifier to relate operations carried out on the same individual. Starting with a total of 1,419,738 NJR source file records, around 12.9% were lost because no suitable person-level identifier was found. In around half of these (48.7%), the patient had declined to give consent for details to be held, the remainder being attributable to tracing and linkage difficulties. A person-level identifier was available for 95.9% of operations from 2008 to 2012 but, in earlier years, the proportion had been much lower, for example, it was 58.9% in 2004. The implication of this is that the subset of patients with longer follow-up may be less representative than those patients with shorter follow-up.
Amongst the patients with person-level identifiers, 4.7% had solely revision operations recorded within the time frame, i.e. they had no primary operation record in the NJR. This was either because the primary had taken place at an earlier point in time (before the NJR data collection period began in 2003) or it had not been included for other reasons; these cases were excluded. This left 945,196 patients with at least one record of a primary joint replacement within the NJR, i.e. hips, knees, ankles, elbows or shoulders.
At the joint level, some further revisions were excluded if they could not be matched to primary joint replacements. For example, if a primary operation was recorded only for one side and there was a documented revision for the other side, the latter was excluded.
The resulting data sets are shown in Table 3.1. Shoulder and elbow replacements are not shown here but will be included in a later Report. Separate sets of analyses have been carried out for hips, knees and ankles, although the numbers for the latter are still quite small.
Table 3.2 opposite shows the composition of the three data sets. Of the 478,730 patients with primary hip operations 12.6% had operations documented for both hips; likewise 19.5% of the 499,015 patients with knee operations had operations on both sides.
Implant survivorship is later described with respect to the lifetime of the primary joint only, i.e. we have looked only at time to first revision, not the time from a revision
operation to any subsequent one. Table 3.2 shows the number of subsequent revision procedures and these numbers are small.
The unit of observation for all sets of survivorship analysis has been taken as the individual primary joint replacement. A patient with left and right replacements of a particular type, therefore, will have two entries, and an assumption is made that the survivorship of a
Table 3.1 Summary description of datasets used for survivorship analysis.
NJR dataSummary of data All NJR procedure-level data restructured to person-level
Time period 1 April 2003 – 31 December 2012
Data exclusions- Excludes data where patient-level identifier is not present- Excludes patients where no primary operation is recorded in the NJR- Excludes any revisions after the first revision
Number of primary operations 539,372 hips; 589,028 knees; 1,417 ankles
Number of revisions linked to a primary operationNJR identified primary-linked first revisions:11,780 hips; 11,666 knees; 9 ankles©
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replacement on one side is independent of the other. In practice it would be difficult to validate this, particularly given that some patients had had prior replacements not recorded in the NJR. Risk factors such as age are recorded at the time of primary operation and will therefore be different for the two procedures unless the two operations are performed at the same time.
A further complication is that patients may have more than one type of implant.
Figure 3.1 shows the overlap amongst patients in the dataset. For example, 443,190 patients had only hip operations in the data base, 35,422 had both hip and knee replacements and a further 24 had hip, knee and ankles. We stress this is only the composition within the NJR; ankle operations have only recently been included and so the figures are not generalisable.
Figure 3.1 Patients with hip, knee and ankle primary operations within the survivorship data sets.
Table 3.2 Composition of person-level datasets for survivorship analysis.
Hips Knees Ankles
Number Number Number
Number of patients 478,730 499,015 1,388
Number (%) of patients with only one primary joint operation 418,088 (87.3%) 409,002 (82.0%) 1,359 (97.9%)Number (%) of patients with different operation dates for left and right sides of the same primary joint
57,550 (12.0%) 82,440 (16.5%) 27 (1.9%)
Number (%) of patients with bilateral operations (both sides of the same primary joint replaced at the same time)
3,092 (0.6%) 7,573 (1.5%) 2 (0.1%)
Total number of primary joints 539,372 589,028 1,417
Number with at least one revision operation linked to the primary 11,780 11,666 9
Number with more than one revision procedure 1,524 1,821 0
HIPS ANKLES
KNEES463,368
443,190 1,069
35,422 201
94
24
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Part 33.2 Outcomes after primary hip replacement
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This section looks at revision and mortality for all primary hip operations performed between 1 April 2003 and 31 December 2012. Patients operated on at the beginning of the registry therefore had a potential for nearly 10 years follow up.
Details of the patient cohort are given in Tables 3.1 and 3.2 of the preceding section; a total of 539,372 hips were included.
Methodological note
Survival analyses have been used throughout this section, first looking at the need for revision and then looking at mortality. For revision, only the first revision has been considered here. The majority of implants did not require revision and survival analysis made use of the information that was available on them, i.e. that they had not been revised up to the end of the follow up period (the end of 2012) or prior to their death; these observations were regarded as being ‘censored’ at those times. For mortality, the event was death, censoring only those cases that were still alive at the end of 2012 (and not for any revision procedure).
The survival tables below show ‘Kaplan-Meier’ estimates of the cumulative chance (probability) of revision, or death, at different times from the primary operation. This is instead of the Nelson-Aalen estimates of ‘cumulative hazard’ used in earlier annual reports, a change that brings us more into line with other registries. Please see the Annexe to Survival Analysis at the end of the chapter for a fuller explanation of the change. Where rates are
very small, the cumulative probability and cumulative hazard are numerically very similar, but with more extended follow up, they have started to diverge.
Cumulative hazard estimates have continued to be used for graphs that compare the survival experiences of different sub-groups. Although either Kaplan-Meier or cumulative hazards could be used for visual comparison, the latter have some advantage - again see our Annexe.
The cumulative hazard plots now also include tables of the numbers at risk at each anniversary. These are particularly useful where a particular group has appeared to ‘plateau’ it may simply be because the number of cases fell so low that the occurrence of further revisions/deaths became unlikely.
All the Kaplan-Meier estimates shown have been multiplied by 100, therefore estimate cumulative percentage probability.
In the case of revisions, no attempt has been made to adjust for the competing risk of death.
Terminology note
The six main categories of bearing surfaces for hip replacements are ceramic-on-ceramic (CoC), ceramic-on-metal (CoM), ceramic-on-polyethylene (CoP), metal-on-metal (MoM), metal-on-polyethylene (MoP) and resurfacing procedures. The metal-on-metal group in this section refers
to patients with a stemmed prosthesis and metal bearing surfaces (a monobloc metal acetabular cup or a metal acetabular cup with a metal liner). Although they have metal-on-metal bearing surfaces, resurfacing procedures, which have a surface replacement femoral prosthesis combined with a metal acetabular cup, are treated as a separate category.
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Table 3.3 Numbers (%) of primary hip replacements by fixation and, within each fixation sub-group, by bearing surface.
Fixation Number (%)Bearing surface within
fixation groupNumber (%)
All cases 539,372 (100.0%) 539,372 (100.0%)
All cemented 201,580 (37.4%)
MoPMoMCoP
Others/unsure
178,077 (33.0%)1,229 (0.2%)
17,202 (3.2%)5,072 (0.9%)
All uncemented 205,317 (38.1%)
MoPMoMCoPCoCCoM
Others/unsure
74,762 (13.9%)28,367 (5.3%)27,964 (5.2%)
67,922 (12.6%)2,017 (0.4%)4,285 (0.8%)
All hybrid 84,671 (15.7%)
MoPMoMCoPCoC
Others/unsure
55,585 (10.3%)2,297 (0.4%)9,720 (1.8%)
15,239 (2.8%)1,830 (0.3%)
All reverse hybrid 12,296 (2.3%)MoPCoP
Others/unsure
8,397 (1.6%)3,816 (0.7%)
83 (<0.1%)All resurfacing 35,470 (6.6%) (MoM) 35,470 (6.6%)
Unsure 38 (<0.1%) Unsure 38 (<0.1%)
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3.2.1 Overview of primary hip surgery
Table 3.3 below shows the breakdown of cases by method of fixation and, within each fixation sub-group, by bearing surface.
The most commonly used type overall remained cemented metal-on-polyethylene (33%).
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Table 3.4 shows the distribution of fixation/bearing surface groups for each year of primary operation.
The percentage of cemented metal-on-polyethylene, the most popular type of implant, has been falling with
time whereas the percentages of both the uncemented and hybrid metal-on-polyethylene have been increasing.
The proportions of metal-on-metal and resurfacing implants have been falling since 2008.
Table 3.4 Percentage of primary hip replacements performed each year by type of hip fixation and constraint.
Fixation/bearing
Percentage of hip replacements by year of primary operation2003
n=14,410
2004n=
27,974
2005n=
40,125
2006n=
47,455
2007n=
60,375
2008n=
66,586
2009n=
67,384
2010n=
69,649
2011n=
72,248
2012n=
73,166All cemented 60.5 54.2 48.6 42.8 39.8 34.3 31.9 31.4 32.4 33.2
Cemented by bearing surface:
MoP 55.3 49.0 43.9 38.4 35.7 30.4 28.2 27.2 27.6 28.6
MoM 0.2 0.4 0.4 0.4 0.4 0.4 0.1 0.1 0.1 0.1
CoP 3.0 3.5 3.1 3.0 2.6 2.7 2.9 3.3 3.5 4.1
Others/unsure 2.0 1.3 1.2 1.0 1.1 0.9 0.6 0.9 1.2 0.4
All uncemented 16.8 21.4 25.6 30.0 33.3 39.3 43.1 45.7 44.9 44.8
Uncemented by bearing surface:
MoP 6.2 9.0 9.8 10.3 10.8 13.1 15.1 16.9 17.1 17.8
MoM 1.3 2.2 5.4 8.3 10.3 10.9 8.0 3.2 0.5 0.1
CoP 5.0 5.1 5.1 4.3 4.0 3.9 4.7 5.6 6.1 7.3
CoC 3.5 4.2 4.4 6.2 7.3 10.1 13.6 18.1 20.1 19.2
CoM 0.0 <0.05 <0.05 <0.05 0.1 0.4 0.9 1.0 0.4 0.1
Others/unsure 0.9 0.8 0.9 0.9 0.9 1.0 0.9 0.9 0.7 0.3
All hybrid 12.3 13.3 14.1 15.2 15.0 15.1 15.8 16.2 17.2 17.6
Hybrid by bearing surface:
MoP 8.2 9.1 9.2 9.7 9.8 9.7 10.4 10.8 11.5 11.5
MoM 0.7 0.5 0.5 0.7 0.8 0.9 0.4 0.2 0.1 <0.05
CoP 1.6 1.5 1.2 1.3 1.1 1.4 1.8 2.0 2.3 3.1
CoC 1.2 1.9 2.7 3.2 2.9 2.7 2.9 3.0 3.1 2.8
Others/unsure 0.7 0.4 0.5 0.5 0.4 0.4 0.3 0.3 0.3 0.1
All reverse hybrid 0.6 0.9 1.1 1.2 1.8 2.5 2.7 2.8 3.1 3.1
Reverse hybrid by bearing surface:
MoP 0.4 0.6 0.7 0.8 1.1 1.7 1.9 1.9 2.2 2.0
CoP 0.3 0.2 0.3 0.3 0.6 0.7 0.8 0.9 0.9 1.1
Others/unsure <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05All resurfacing (MoM)
9.8 10.2 10.7 10.8 10.2 8.8 6.5 3.8 2.5 1.3
All types 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0
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The primary operations were carried out by a total of 2,772 consultant surgeons across 456 units. The median number of primary procedures per consultant was 64, inter-quartile range (IQR) 10-244 and the median number of procedures per unit was 910.5, IQR 419.5-1677.
Table 3.5 below shows the distributions of consultant surgeon and unit caseloads for each type of fixation; consultants and units with fewer than 10 cases in the database have been excluded (683 of 2,772 consultant surgeons and 11 of 456 units).
The table shows, for each fixation type, the percentage of surgeons or units that carried out
procedures of that type, together with the median and IQR of the number of procedures they carried out.
Surgeons performing cemented THR carried out a median of 43 operations over the period they were observed with IQR 13 to 126 procedures. This means that 25% of surgeons performed fewer than 13 cemented hip replacements and 25% more than 126. Additionally, 10% of surgeons carrying out cemented hip replacements had performed between 782 and 1,390 procedures (not shown in table). Similarly, the surgeons with the highest 10% of caseloads performing uncemented THR carried out between 917 and 2,614 procedures over the period of observation.
Table 3.5 Distribution of consultant surgeon and unit caseload for each fixation type.
Fixation
Number of procedures carried out by consultant surgeons (n=2,089):
Number of procedures carried out by units (n=445):
% performing this fixation
type Median (IQR)
% performing this fixation
type Median (IQR)Cemented 95.2 43 (13-126) 99.6 252 (83-645)
Uncemented 84.4 38 (8-147) 98.0 296 (120.5-622.5)
Hybrids 71.3 11 (3-50) 94.6 69 (14-208)
Reverse hybrids 36.6 2 (1-8.5) 74.4 6 (2-25)
Resurfacing 37.2 12 (2-46) 88.1 46 (14.5-107)© N
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The median age at operation was 69 (IQR 61-76; range 7-105) years.10
Table 3.6 gives the breakdown of ages by fixation and by the main bearing surfaces within each fixation
sub-group. On the whole, resurfacing and ceramic-on-ceramic bearings tended to be used in younger patients although the age ranges were wide.
10 15 ages were 0 and assumed missing.
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13*IQR=inter-quartile range; **Excludes all sub-groups with ‘other/unsure’ bearing surfaces, ***The bearing surface for the 7 year old was other or unsure so not shown in sub groups presented.
Table 3.6 Age (in years) at primary hip replacement, by fixation and main bearing surface.
FixationBy bearing surface within
fixation group**Median (IQR*; range) of ages Minimum age Maximum age
All cases 69 (61-76) 7 105
All cemented 74 (68-79) 7*** 103
Cemented and
MoP 74 (69-79) 15 103
MoM 65 (58-73) 25 98
CoP 65 (59-71) 16 101
All uncemented 65 (58-72) 9 105
Uncemented and
MoP 71 (65-77) 14 101
MoM 64 (57-70) 13 105
CoP 65 (59-71) 13 100
CoC 61 (53-67) 9 100
CoM 63 (56-69) 20 92
All hybrid 70 (62-76) 12 100
Hybrid and
MoP 73 (67-78) 12 100
MoM 63 (56-71) 15 93
CoP 65 (59-72) 16 96
CoC 60 (54-66) 13 92
All reverse hybrid 71 (64-77) 13 100
Reverse hybrid and
MoP 73 (68-78) 13 100
CoP 64 (59-70) 16 94
All resurfacing 55 (49-60) 12 95
Resurfacing and
MoM 55 (49-60) 12 95
3.2.2 Revisions after primary hip surgery
Table 3.7 shows Kaplan-Meier estimates of the cumulative percentage probability of first revision, for any cause, for all cases combined and then subdivided by fixation and bearing surface within each fixation group. Estimates are shown, together with 95% Confidence Intervals (95% CI), at 30 and 90 days after the primary operation and at each anniversary up to the ninth year. These do not adjust for other factors such as age and gender.
At time points where the estimates are shown in italics, fewer than 100 cases remained at risk; if the numbers at risk are small, revisions, as they occur, may appear to have greater impact on the failure rate estimates, i.e. the step upwards may appear steeper.
Amongst the cemented hips, the revision rate at nine years
was highest for metal-on-metal. This is further exemplified by Figure 3.2, where the cumulative hazard for the three bearing surface groups are plotted together. The shaded bands in these figures indicate point-wise 95% CIs for the estimates.
A similar picture exists for uncemented hips, see Figure 3.3, namely that the metal-on-metal revision rates were the highest, higher even than those for resurfacing.
Amongst the hybrid hips, again the revision rates for metal-on-metal were highest – see Figure 3.4.
For the cumulative hazard curves for metal-on-metal in Figures 3.2 to 3.4, the tangents appeared to increase over the 9 years of follow up, suggesting that the hazard rate (the rate of revision amongst the unrevised cases) increased with time from primary operation.
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*Incl
udin
g th
e 38
with
uns
ure
fixat
ion/
bear
ing
surfa
ce; *
* W
ide
CIs
bec
ause
bas
ed o
n a
smal
l gro
up s
ize
(n=
83)
Tab
le 3
.7 K
apla
n-M
eier
est
imat
es o
f the
cum
ulat
ive
perc
enta
ge p
roba
bilit
y of
firs
t rev
isio
n (9
5% C
I), a
t diff
eren
t tim
es a
fter
the
prim
ary
oper
atio
n,
for
each
fixa
tion/
bear
ing
surfa
ce s
ub-g
roup
. For
the
estim
ates
in b
lue
italic
s, fe
wer
than
100
cas
es r
emai
n at
ris
k.
Fixa
tion/
bea
ring
typ
es30
day
s90
day
s1
year
2 ye
ars
3 ye
ars
4 ye
ars
5 ye
ars
6 ye
ars
7 ye
ars
8 ye
ars
9 ye
ars
All
case
s*0.
24
(0.2
3-0.
25)
0.40
(0.3
8-0.
42)
0.75
(0
.72-
0.77
)1.
20
(1.1
7-1.
23)
1.66
(1.6
2-1.
69)
2.15
(2.1
1-2.
20)
2.75
(2.6
9-2.
81)
3.38
(3.3
1-3.
45)
3.97
(3.8
8-4.
05)
4.53
(4.4
2-4.
63)
5.06
(4.9
2-5.
21)
All
cem
ente
d0.
12(0
.11-
0.14
)0.
22
(0.2
0-0.
24)
0.44
(0
.41-
0.47
)0.
74
(0.7
0-0.
78)
1.01
(0
.97-
1.06
)1.
24(1
.19-
1.30
)1.
52(1
.45-
1.58
)1.
79(1
.72-
1.87
)2.
09(2
.00-
2.18
)2.
41(2
.29-
2.52
)2.
71(2
.57-
2.87
)C
emen
ted
by
bea
ring
sur
face
:
MoP
0.13
(0.1
1-0.
14)
0.23
(0
.20-
0.25
)0.
45(0
.42-
0.48
)0.
74(0
.70-
0.79
)1.
01(0
.96-
1.06
)1.
24(1
.18-
1.30
)1.
50(1
.43-
1.57
)1.
75(1
.67-
1.83
)2.
02(1
.92-
2.11
)2.
33(2
.22-
2.46
)2.
62(2
.47-
2.78
)
MoM
0.16
(0.0
4-0.
65)
0.24
(0.0
8-0.
76)
0.67
(0.3
3-1.
33)
1.65
(1.0
6-2.
58)
2.87
(2.0
4-4.
04)
4.39
(3.3
1-5.
80)
6.32
(4.9
4-8.
08)
9.20
(7.3
2-11
.52)
12.4
3(9
.93-
15.5
1)14
.38
(11.
40-1
8.06
)21
.43
(15.
41-2
9.36
)
CoP
0.07
(0.0
4-0.
12)
0.14
(0.0
9-0.
20)
0.35
(0.2
7-0.
45)
0.64
(0.5
2-0.
78)
0.88
(0.7
3-1.
06)
1.02
(0.8
5-1.
21)
1.21
(1.0
2-1.
45)
1.41
(1.1
8-1.
68)
1.67
(1.3
9-2.
01)
1.84
(1.5
1-2.
24)
1.84
(1.5
1-2.
24)
Oth
ers/
unsu
re0.
18(0
.09-
0.34
)0.
24(0
.14-
0.42
)0.
51(0
.34-
0.75
)0.
75(0
.54-
1.04
)1.
05(0
.78-
1.42
)1.
20(0
.90-
1.60
)1.
60(1
.22-
2.10
)2.
18(1
.68-
2.84
)2.
55(1
.96-
3.32
)2.
83(2
.15-
3.72
)3.
24(2
.30-
4.57
)
All
unce
men
ted
0.36
(0
.34-
0.39
)0.
55
(0.5
2-0.
58)
0.99
(0.9
5-1.
03)
1.56
(1
.50-
1.62
)2.
19(2
.12-
2.26
)2.
88(2
.79-
2.98
)3.
76(3
.65-
3.88
) 4.
77(4
.62-
4.92
)5.
59(5
.30-
5.68
)6.
23(5
.99-
6.48
)6.
71(6
.40-
7.05
)U
ncem
ente
d b
y b
eari
ng s
urfa
ce:
MoP
0.42
(0.3
7-0.
47)
0.62
(0.5
6-0.
68)
1.06
(0
.98-
1.14
)1.
51(1
.42-
1.61
)1.
93(1
.82-
2.05
)2.
19(2
.07-
2.32
)2.
50(2
.35-
2.65
)2.
92(2
.74-
3.11
)3.
21(3
.00-
3.43
)3.
80(3
.48-
4.14
)4.
30(3
.82-
4.84
)
MoM
0.31
(0.2
6-0.
39)
0.48
(0.4
1-0.
57)
1.02
(0.9
1-1.
14)
1.99
(1.8
4-2.
17)
3.38
(3.1
7-3.
60)
5.24
(4.9
7-5.
52)
7.65
(7.3
0-8.
02)
10.6
5(1
0.16
-11.
16)
13.0
4(1
2.39
-13.
72)
15.5
5(1
4.57
-16.
59)
17.6
6(1
5.93
-19.
56)
CoP
0.30
(0.2
4-0.
37)
0.47
(0.4
0-0.
56)
0.81
(0.7
1-0.
93)
1.17
(1.0
4-1.
32)
1.55
(1.3
9-1.
72)
1.86
(1.6
8-2.
07)
2.16
(1.9
5-2.
40)
2.40
(2.1
6-2.
66)
2.66
(2.3
9-2.
97)
2.89
(2.5
6-3.
25)
3.03
(2.6
5-3.
45)
CoC
0.34
(0.2
9-0.
38)
0.53
(0.4
8-0.
59)
0.96
(0.8
9-1.
04)
1.50
(1.4
0-1.
60)
1.87
(1.7
6-2.
00)
2.20
(2.0
6-2.
34)
2.58
(2.4
1-2.
76)
2.96
(2.7
4-3.
19)
3.41
(3.1
2-3.
72)
3.85
(3.4
6-4.
27)
4.08
(3.5
9-4.
64)
CoM
0.15
(0.0
5-0.
46)
0.20
(0.0
7-0.
53)
0.65
(0.3
8-1.
12)
1.47
(1.0
1-2.
12)
2.94
(2.1
9-3.
95)
4.15
(3.0
6-5.
62)
5.51
(3.5
9-8.
42)
5.51
(3.5
9-8.
42)
5.51
(3.5
9-8.
42)
5.51
(3.5
9-8.
42)
-
Oth
ers/
unsu
re0.
77(0
.55-
1.08
) 0.
87(0
.63-
1.19
)1.
25(0
.96-
1.64
)1.
70(1
.35-
2.15
)2.
18(1
.76-
2.69
)2.
63(2
.14-
3.21
)3.
31(2
.72-
4.02
)4.
08(3
.35-
4.96
)4.
28(3
.51-
5.21
)4.
96(3
.93-
6.26
)5.
75(4
.36-
7.57
)
All
hyb
rid
s0.
22(0
.19-
0.26
)0.
36 (0
.32-
0.40
)0.
65
(0.5
9-0.
71)
0.98
(0
.91-
1.05
)1.
23(1
.15-
1.31
)1.
54(1
.44-
1.64
)1.
88(1
.77-
2.00
)2.
27(2
.13-
2.42
)2.
66(2
.49-
2.85
)2.
99(2
.77-
3.22
)3.
42(3
.10-
3.76
)H
ybri
ds
by
bea
ring
sur
face
:
MoP
0.24
(0.2
0-0.
28)
0.38
(0.3
3-0.
44)
0.69
(0.6
2-0.
77)
1.02
(0.9
3-1.
11)
1.23
(1.1
3-1.
34)
1.46
(1.3
5-1.
59)
1.78
(1.6
5-1.
93)
2.08
(1.9
1-2.
25)
2.35
(2.1
6-2.
57)
2.65
(2.4
0-2.
93)
2.99
(2.6
6-3.
37)
MoM
0.35
(0.1
7-0.
70)
0.44
(0.2
3-0.
81)
0.66
(0.4
0-1.
09)
1.60
(1.1
6-2.
21)
2.98
(2.3
4-3.
78)
4.68
(3.8
5-5.
69)
6.29
(5.2
7-7.
51)
9.34
(7.8
7-11
.06)
12.6
7(1
0.64
-15.
06)
13.9
2(1
1.61
-16.
63)
14.8
6(1
2.05
-18.
25)
CoP
0.11
(0.0
6-0.
21)
0.22
(0.1
4-0.
34)
0.47
(0.3
5-0.
64)
0.69
(0.5
3-0.
90)
0.93
(0.7
3-1.
18)
1.14
(0.9
0-1.
44)
1.37
(1.0
8-1.
73)
1.52
(1.1
9-1.
94)
1.75
(1.3
5-2.
27)
1.97
(1.5
0-2.
60)
2.72
(1.8
8-3.
95)
CoC
0.22
(0.1
6-0.
31)
0.32
(0.2
4-0.
42)
0.54
(0.4
3-0.
67)
0.86
(0.7
2-1.
03)
0.99
(0.8
4-1.
18)
1.27
(1.0
8-1.
50)
1.44
(1.2
3-1.
70)
1.67
(1.4
1-1.
97)
1.87
(1.5
8-2.
26)
2.12
(1.7
3-2.
60)
2.34
(1.8
1-3.
02)
Oth
ers/
unsu
re0.
22
(0.0
8-0.
58)
0.55
(0.3
0-1.
02)
1.12
(0.7
2-1.
73)
1.37
(0.9
2-2.
03)
1.58
(1.0
8-2.
30)
1.85
(1.2
9-2.
65)
2.06
(1.4
4-2.
92)
2.49
(1.7
5-3.
53)
2.93
(2.0
4-4.
21)
3.39
(2.2
5-5.
10)
4.07
(2.5
4-6.
50)
All
reve
rse
hyb
rid
s0.
16(0
.10-
0.24
)0.
31(0
.23-
0.43
)0.
76
(0.6
1-0.
93)
1.11
(0
.92-
1.33
)1.
48
(1.2
5-1.
75)
1.76
(1.4
9-2.
08)
2.13
(1.7
8-2.
53)
2.46
(2.0
4-2.
96)
2.99
(2.4
1-3.
72)
3.31
(2.5
2-4.
33)
3.31
(2.5
2-4.
33)
Res
erve
hyb
rid
s b
y b
eari
ng s
urfa
ce:
MoP
0.18
(0.1
1-0.
30)
0.35
(0.2
4-0.
50)
0.81
(0.6
3-1.
03)
1.13
(0.9
1-1.
40)
1.42
(1.1
6-1.
74)
1.71
(1.4
0-2.
10)
2.20
(1.7
7-2.
72)
2.55
(2.0
2-3.
20)
3.02
(2.3
2-3.
91)
3.02
(2.3
2-3.
91)
3.02
(2.3
2-3.
91)
CoP
0.11
(0.0
4-0.
28)
0.21
(0.1
1-0.
43)
0.63
(0.4
2-0.
96)
1.01
(0.7
1-1.
43)
1.54
(1.1
3-2.
10)
1.79
(1.3
3-2.
42)
1.94
(1.4
1-2.
65)
2.11
(1.5
2-2.
92)
2.80
(1.8
3-4.
26)
3.67
(2.0
9-6.
40)
3.67
(2.0
9-6.
40)
Oth
ers/
unsu
re**
0.00
1.23
(0.1
7-8.
44)
1.23
(0.1
7-8.
44)
2.61
(0.6
6-10
.04)
4.10
(1.3
4-12
.24)
4.10
(1.3
4-12
.24)
4.10
(1.3
4-12
.24)
7.94
(2.6
5-22
.50)
7.94
(2.6
5-22
.50)
7.94
(2.6
5-22
.50)
7.94
(2.6
5-22
.50)
All
resu
rfac
ing
(Mo
M)
0.25
(0.2
0-0.
31)
0.66
(0.5
8-0.
75)
1.27
(1.1
6-1.
39)
2.18
(2.0
3-2.
34)
3.14
(2.9
6-3.
33)
4.39
(4.1
7-4.
63)
5.82
(5.5
5-6.
10)
7.32
(7.0
0-7.
65)
9.02
(8.6
3-9.
43)
10.5
4(1
0.05
-11.
05)
12.3
1(1
1.62
-13.
04)
© National Joint Registry 2013
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
133www.njrcentre.org.uk
Figure 3.2 Comparison of cumulative hazard of first revision for cemented hips with different bearing surfaces (with 95% CI).
0
5
10
15
20
25
30
35
0 1 2 3 4 5 6 7 8 9
Years since primary surger
Numbers at risk
y
Cum
ulat
ive
haza
rd x
100
1 2 3 4 5 6 7 98Cemented MoP
Cemented MoM
Cemented CoP
178,077
1,229
17,202
152,981
1,151
14,022
130,206
1,072
11,325
108,931
1,002
8,961
88,203
880
6,984
67,448
612
5,172
47,008
397
3,652
30,708
216
2,319
16,134
96
1,164
5,594
15
344
© N
atio
nal J
oint
Reg
istr
y 20
13
134 www.njrcentre.org.uk
Figure 3.3 Comparison of cumulative hazard of first hip revision for uncemented hips with different bearing surfaces (with 95% CI).
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9
Years since primary surgery
Cum
ulat
ive
haza
rd x
100
Uncemented MoP
Uncemented MoM
Uncemented CoP
74,762
28,367
27,964
67,922
2,017
35,470
60,095
27,716
22,234
53,029
1,942
33,989
47,032
26,841
17,670
38,276
1,621
31,820
34,874
24,022
13,639
25,689
921
28,841
24,669
18,424
10,443
16,673
310
24,276
16,385
11,517
7,877
10,147
53
18,459
10,371
5,880
5,538
5,918
10
12,547
6,010
2,476
3,617
3,134
1
7,759
2,689
648
1,832
1,512
1
3,881
670
142
602
445
0
1,273
Uncemented CoC
Uncemented CoM
Resurfacing
Numbers at risk
© N
atio
nal J
oint
Reg
istr
y 20
13
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
135www.njrcentre.org.uk
Figure 3.4 Comparison of cumulative hazard of a first hip revision for hybrid (not including reverse hybrid) hips with different bearing surfaces (with 95% CI).
0
5
10
15
20
0 1 2 3 4 5 6 7 8 9
Years since primary surgery
Cum
ulat
ive
haza
rd x
100
Hybrid MoP
Hybrid MoM
Hybrid CoP
55,585
2,297
9,720
15,239
45,908
2,247
7,357
13,020
37,004
2,145
5,673
10,672
29,075
1,951
4,295
8,584
21,909
1,627
3,092
6,592
15,596
1,073
2,189
4,802
10,122
610
1,559
3,104
6,095
338
993
1,690
2,957
190
548
671
911
79
187
163Hybrid CoC
Numbers at risk
© N
atio
nal J
oint
Reg
istr
y 20
13
136 www.njrcentre.org.uk
Table 3.8 shows the revision rates for each case, for all cases and broken down by fixation and, within each fixation group, by bearing surface. In the initial years of the formation of the registry, adverse soft tissue reaction was not included in the clinical assessment forms. Therefore, there were fewer ‘patient-years at risk’ for this reason.
The main reasons for revision were pain and aseptic loosening; resurfacing seemed to have the highest incidence of each, with uncemented hips a close
contender. Resurfacings also appeared to have the highest incidence of adverse soft tissue reactions. The incidence of dislocation/subluxation, however, was lowest for resurfacings.
After further subdivision by bearing surface, amongst the cemented, uncemented and hybrid fixation groups, the metal-on-metal sub-groups had the highest incidences of pain and aseptic loosening and also appeared to have the highest incidences of adverse soft tissue reactions.
Methodological note
The previous section looked at revisions for any reason. A number of reasons may be associated with any revision; for example, pain and osteolysis. This means the reasons are not mutually exclusive and therefore cannot be regarded as representing ‘competing risks’. Here we have calculated incidence rates for each reason using patient-
time incidence rates (PTIRs); the total number of revisions for that reason has been divided by the total of the individual patient-years at risk. The figures shown are the numbers per 1,000 years at risk. This method is appropriate if the hazard rate (the rate at which revisions occur in the unrevised cases) remains constant. The latter is explored further later in this section.
3.2.3 Revisions for different causes after primary hip surgery
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
137www.njrcentre.org.uk
*Including the 38 with unknown fixation/bearing. **Based on a small group size (n=83), therefore estimates are unreliable.
Table 3.8 Revision rates (95% CI), expressed as number of revisions per 1,000 patient-years, for each recorded reason for first hip revision. Rates shown are for all revised cases and by fixation and bearing surface.
Fixation/bearing types
Patient-years at risk
(x1,000)
Number of revisions per 1,000 patient-years for:
PainDislocation/ subluxation Infection
Aseptic loosening Lysis
Periprosthetic fracture
Implant fracture
All cases* 2,026.41.37
(1.32-1.42)1.03
(0.99-1.08)0.83
(0.80-0.88)1.44
(1.39-1.49)0.29
(0.27-0.31)0.64
(0.61-0.68)0.17
(0.15-0.19)
All Cemented 824.50.48
(0.44-0.53)0.89
(0.83-0.96)0.79
(0.73-0.85)0.93
(0.87-1.00)0.18
(0.15-0.21)0.30
(0.27-0.34)0.06
(0.05-0.08)
Cemented by bearing surface:
MoP 735.10.45
(0.40-0.50)0.92
(0.85-0.99)0.78
(0.72-0.84)0.93
(0.86-1.00)0.17
(0.15-0.21)0.31
(0.27-0.35)0.05
(0.04-0.07)
MoM 6.14.13
(2.79-6.11)0.83
(0.34-1.99)1.16
(0.55-2.43)4.13
(2.79-6.11)1.65
(0.89-3.07)1.16
(0.55-2.43)0.83
(0.34-2.00)
CoP 62.40.43
(0.30-0.63)0.69
(0.51-0.93)0.87
(0.66-1.13)0.67
(0.50-0.91)0.11
(0.05-0.24)0.10
(0.04-0.21)0.05
(0.02-0.15)
Others/unsure 20.90.62
(0.36-1.07)0.62
(0.36-1.07)0.96
(0.62-1.48)0.91
(0.58-1.43)0.14
(0.05-0.45)0.34
(0.16-0.70)0.24
(0.10-0.58)All uncemented
680.81.85
(1.75-1.95)1.29
(1.21-1.38)0.97
(0.89-1.04)1.94
(1.84-2.05)0.31
(0.27-0.35)0.82
(0.75-0.89)0.28
(0.24-0.32)
Uncemented by bearing surface:
MoP 239.60.99
(0.87-1.12)1.62
(1.47-1.79)0.89
(0.78-1.02)1.53
(1.38-1.70)0.20
(0.15-0.27)1.01
(0.89-1.15)0.12
(0.08-0.17)
MoM 132.15.32
(4.94-5.73)1.10
(0.93-1.29)1.60
(1.40-1.83)3.44
(3.14-3.77)0.82
(0.68-0.99)0.64
(0.51-0.79)0.16
(0.10-0.24)
CoP 97.20.76
(0.61-0.96)1.20
(1.00-1.44)0.64
(0.50-0.82)1.44
(1.22-1.70)0.16
(0.10-0.27)0.51
(0.39-0.68)0.14
(0.09-0.24)
CoC 188.21.10
(0.96-1.26)1.05
(0.92-1.21)0.80
(0.68-0.94)1.64
(1.46-1.83)0.13
(0.09-0.19)0.83
(0.71-0.97)0.63
(0.53-0.76)
CoM 5.92.37
(1.40-4.00)1.19
(0.57-2.49)1.52
(0.79-2.93)2.71
(1.66-4.42)0.68
(0.25-1.80)0.34
(0.08-1.35)0.17
(0.02-1.20)
Others/unsure 17.91.40
(0.95-2.07)1.34
(0.90-2.00)0.56
(0.30-1.04)2.13
(1.55-2.93)0.50
(0.26-0.97)1.18
(0.77-1.80)0.39
(0.19-0.82)
All hybrid 304.00.73
(0.64-0.84)1.19
(1.07-1.32)0.74
(0.65-0.84)0.83
(0.73-0.94)0.25
(0.20-0.31)0.65
(0.56-0.75)0.12
(0.08-0.16)
Hybrids by bearing surface:
MoP 196.90.52
(0.43-0.63)1.35
(1.20-1.52)0.77
(0.66-0.91)0.80
(0.69-0.94)0.23
(0.17-0.31)0.68
(0.57-0.80)0.09
(0.06-0.15)
MoM 11.44.54
(3.46-5.96)1.84
(1.20-2.82)0.96
(0.53-1.74)2.97
(2.12-4.16)1.49
(0.92-2.39)1.66
(1.06-2.60)0.17
(0.04-0.70)
CoP 30.60.62
(0.40-0.97)0.98
(0.69-1.40)0.65
(0.42-1.01)0.52
(0.32-0.85)0.13
(0.05-0.35)0.46
(0.27-0.77)0.03
(0.005-0.23)
CoC 56.90.69
(0.50-0.94)0.65
(0.47-0.90)0.55
(0.38-0.78)0.65
(0.47-0.90)0.11
(0.05-0.23)0.47
(0.33-0.69)0.25
(0.15-0.42)
Others/unsure 8.21.34
(0.74-2.41)0.85
(0.41-1.78)1.34
(0.74-2.41)0.85
(0.41-1.78)0.49
(0.18-1.29)0.49
(0.18-1.29)0
All reverse hybrid
36.2 0.86
(0.60-1.22)1.19
(0.88-1.60)1.08
(0.79-1.48)1.38
(1.05-1.82)0.11
(0.04-0.29)0.61
(0.40-0.92)0.08
(0.03-0.26)
Reverse hybrids by bearing surface:
MoP 24.60.57
(0.34-0.96)1.30
(0.92-1.84)1.14
(0.79-1.65)1.22
(0.85-1.75)0.08
(0.02-0.33)0.69
(0.43-1.11)0.08
(0.02-0.33)
CoP 11.31.51
(0.94-2.43)0.98
(0.54-1.76)0.98
(0.54-1.76)1.60
(1.01-2.54)0.18
(0.04-0.71)0.44
(0.18-1.07)0.09
(0.01-0.63)Others/unsure**
0.3 0 0 06.26
(1.57-25.03)0 0 0
All Resurfacing (MoM)
180.64.78
(4.47-5.11)0.43
(0.34-0.53)0.65
(0.55-0.78)2.92
(2.68-3.18)0.82
(0.70-0.97)1.57
(1.39-1.76)0.35
(0.28-0.45)
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Table 3.8 (continued)
Fixation/bearing types
Patient-years at risk (x1,000)
Number of revisions per 1,000 patient-years for:
Patient-years at risk (x1,000)
Adversesoft tissuereaction***Implant failure
Head/socket mismatch Malalignment
Other indication
All cases* 2,026.400.28
(0.26-0.31)0.06
(0.05-0.07)0.50
(0.47-0.53)0.66
(0.63-0.70)797.5
0.68 (0.63-0.74)
All Cemented 824.50.11
(0.09-0.14)0.03
(0.02-0.04)0.27
(0.24-0.31)0.19
(0.16-0.22)260.4
0.04 (0.02-0.07)
Cemented by bearing surface:
MoP 735.10.10
(0.08-0.13)0.03
(0.02-0.04)0.28
(0.24-0.32)0.17
(0.14-0.20)227.6
0.02 (0.01-0.05)
MoM 6.11.16
(0.55-2.43)0.17
(0.02-1.20)0.33
(0.08-1.32)2.97
(1.87-4.72)1.6
3.10 (1.30-7.40)
CoP 62.40.14
(0.08-0.28)0.02
(0.002-0.11)0.22
(0.13-0.38)0.14
(0.08-0.28)24.4 0
Others/unsure 20.90.10
(0.02-0.38)0
0.24 (0.10-0.58)
0.24 (0.10-0.58)
6.8 0
All uncemented 680.80.50
(0.45-0.55)0.10
(0.08-0.13)0.72
(0.66-0.78)0.96
(0.89-1.03)340.5
1.02 (0.91-1.13)
Uncemented by bearing surface:
MoP 239.60.43
(0.35-0.52)0.09
(0.06-0.13)0.71
(0.61-0.83)0.46
(0.38-0.55)120.0
0.18 (0.12-0.28)
MoM 132.10.95
(0.79-1.13)0.09
(0.05-0.16)0.95
(0.80-1.14)2.57
(2.31-2.86)51.7
5.50 (4.90-6.20)
CoP 97.20.35
(0.25-0.49)0.09
(0.05-0.18)0.54
(0.41-0.70)0.55
(0.42-0.71)38.8
0.10 (0.04-0.27)
CoC 188.20.35
(0.28-0.45)0.12
(0.08-0.18)0.63
(0.53-0.76)0.72
(0.61-0.85)117.1
0.19 (0.12-0.29)
CoM 5.90.68
(0.25-1.80)0.17
(0.02-1.20)1.19
(0.57-2.49)0.85
(0.35-2.03)5.6
1.60 (0.84-3.10)
Others/unsure 17.90.34
(0.15-0.75)0.17
(0.05-0.52)0.73
(0.42-1.25)0.56
(0.30-1.04)7.4
0.67 (0.28-1.60)
All hybrid 304.00.24
(0.19-0.31)0.03
(0.01-0.05)0.40
(0.33-0.48)0.34
(0.28-0.41)128.6
0.14 (0.09-0.22)
Hybrids by bearing surface:
MoP 196.90.24
(0.18-0.32)0.03
(0.01-0.06)0.42
(0.34-0.52)0.23
(0.17-0.31)84.2
0.04 (0.01-0.11)
MoM 11.40.35
(0.13-0.93)0.17
(0.04-0.70)0.96
(0.53-1.74)2.62
(1.83-3.75)3.5
3.70 (2.10-6.30)
CoP 30.60.20
(0.09-0.44)0
0.16 (0.07-0.39)
0.29 (0.15-0.57)
14.4 0
CoC 56.90.23
(0.13-0.39)0.02
(0.00(2)-0.12)0.37
(0.24-0.57)0.30
(0.19-0.48)23.5
0.09 (0.02-0.34)
Others/unsure 8.20.36
(0.12-1.13)0
0.24 (0.06-0.97)
0.36 (0.12-1.13)
3.0 0
All reverse hybrid 36.2 0.14
(0.06-0.33)0.06
(0.01-0.22)0.41
(0.25-0.69)0.39
(0.23-0.65)20.4 0
Reverse hybrids by bearing surface:
MoP 24.60.12
(0.04-0.38)0.08
(0.02-0.33)0.45
(0.25-0.81)0.37
(0.19-0.70)13.8 0
CoP 11.30.18
(0.04-0.71)0
0.36 (0.13-0.95)
0.36 (0.13-0.95)
6.4 0
Others/unsure** 0.3 0 0 03.13
(0.44-22.00)0.1 0
All Resurfacing (MoM)
180.60.36
(0.28-0.46)0.12
(0.08-0.18)0.93
(0.80-1.08)2.27
(2.06-2.50)47.6
3.55 (3.05-4.13)
*Including the 38 with unknown fixation/bearing. **Based on a small group size (n=83), therefore estimates are unreliable. ***This reason was not asked in the early versions of the clinical assessment forms MDSv1 and MDSv2 for joint replacement/revision surgery and hence, for this reason, there are fewer patient-years at risk.
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
139www.njrcentre.org.uk
Table 3.9 illustrates how the risk of revision (for any reason) changed with time from primary operation.
The number of revisions per 1,000 patient-years was calculated for different periods after the primary operation, within the first year from primary operation, and between 1-3, 3-5, 5-7 and 7+ years after surgery.
Note the maximum follow-up for any implant was 9.75 years.
The rate was higher initially, with a small decrease between one and three years, after which the rate began to rise. The rates were less reliable after seven years because there were fewer patient-years at risk.
Table 3.9 Revision rates, expressed as numbers per 1,000 patient-years, for any reason, according to time interval from primary operation.
Time from primary operation Patient-years at risk (x1,000) Revision rate per 1,000 patient-years (95% CI)
<1 year 497.6 7.71 (7.47-7.96)
1-3 years 756.8 4.60 (4.45-4.75)
3-5 years 469.0 5.51 (5.30-5.72)
5-7 years 227.8 6.36 (6.04-6.69)
>7 years* 75.1 5.75 (5.23-6.32)
*current maximum observed follow up is 9.75 years
In Table 3.10 the breakdown of Table 3.9 has been repeated, this time showing separate breakdowns for each reason. There were trends of increasing risk of pain and aseptic loosening with time. Risk of
subluxation/dislocation, infection and periprosthetic fracture were highest early on, then fell. Incidence of adverse soft tissue reaction seemed to increase with time.
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Table 3.10 Revision rates (95% CI), expressed as numbers per 1,000 patient-years, for each reason, by time interval from primary operation.
Time from primary operation
Patient-years
at risk (x1,000)
Number of revisions per 1,000 patient-years for:
PainDislocation/ subluxation Infection
Aseptic loosening Lysis
Periprosthetic fracture
Implant fracture
<1 year 497.60.85
(0.77-0.94)2.32
(2.19-2.45)1.28
(1.18-1.38)1.28
(1.18-1.38)0.10
(0.07-0.13)1.49
(1.38-1.60)0.27
(0.22-0.31)
1-3 years 756.81.25
(1.17-1.33)0.66
(0.61-0.72)0.87
(0.80-0.93)1.38
(1.30-1.47)0.21
(0.18-0.25)0.29
(0.26-0.33)0.14
(0.12-0.17)
3-5 years 469.01.77
(1.66-1.90)0.55
(0.48-0.62)0.58
(0.51-0.65)1.48
(1.38-1.60)0.40
(0.34-0.46)0.39
(0.34-0.46)0.12
(0.09-0.16)
5-7 years 227.8 1.96
(1.79-2.15)0.58
(0.48-0.68)0.44
(0.36-0.53)1.75
(1.59-1.93)0.56
(0.47-0.66)0.54
(0.46-0.65)0.17
(0.12-0.23)>7 years***
75.1 1.72
(1.44-2.04)0.75
(0.57-0.97)0.39
(0.27-0.56)1.88
(1.59-2.21)0.84
(0.65-1.07)0.48
(0.35-0.66)0.15
(0.08-0.26)
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Time from primary operation
Patient-years at risk
(x1,000)
Number of revisions per 1,000 patient-years for: Patient-years at risk
(x1,000)
Adverse soft tissue reaction**
Implant failure
Head/socket mismatch Malalignment
Other indication
<1 year 497.60.26
(0.22-0.31)0.12
(0.10-0.16)0.91
(0.83-0.99)0.81
(0.74-0.90)301.0
0.10 (0.07-0.15)
1-3 years 756.80.16
(0.13-0.19)0.05
(0.03-0.07)0.40
(0.36-0.45)0.57
(0.52-0.63)376.3
0.71 (0.63-0.80)
3-5 years 469.00.36
(0.31-0.42)0.03
(0.01-0.05)0.35
(0.30-0.41)0.69
(0.62-0.77)116.2
2.04 (1.80-2.32)
5-7 years 227.8 0.51
(0.42-0.61)0.03
(0.01-0.06)0.31
(0.25-0.39)0.61
(0.52-0.73)3.4
2.36 (1.18-4.72)
>7 years*** 75.1 0.52
(0.38-0.71)0.04
(0.01-0.12)0.39
(0.27-0.56)0.48
(0.35-0.66)0.6
1.80 (0.25-1.30)
Table 3.10 (continued)
*Includes the 38 with unknown fixation/bearing. ** This reason was not asked in the early versions of the clinical assessment forms MDSv1 and MDSv2 for joint replacement/revision surgery and hence, for these reasons, there are fewer patient-years at risk. ***Current maximum observed follow up is 9.75 years.
Note on dislocations/subluxation: There were 2097 first revisions performed where dislocations/subluxation was given as a reason (out of all 539,372 operations); in 1,361 of these (64.9%) dislocation/subluxation was the only given reason. From tables 3.9-3.10 above, revisions due to dislocation/subluxation were more common in uncemented and hybrid/reverse hybrid hips than cemented hips and were more common within the first year after primary operation.
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3.2.4 Revisions after primary hip surgery for the main stem-cup brand combinations
Table 3.11 show Kaplan-Meier estimates of the cumulative percentage probability of revision (for any reason) for the main stem-cup brands.
As in our previous reports, we have only included those stem-cup combinations with more than 2,500 procedures in the case of cemented, uncemented, hybrid and reverse hybrid hips, and more than 1,000 in the case of resurfacings.
The figures in italics were at time points where fewer than 100 cases remained at risk.
Note it is possible that these sub-groups may differ in composition with respect to other factors that might influence revision, such as age and gender; no attempt here has been made to adjust for such factors.
Some further subdivisions by bearing type, however, are shown in the table that immediately follows, Table 3.12.
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
141www.njrcentre.org.uk
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Table 3.11 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) at different times after the primary operation, for cup-stem brand combinations with large group sizes (>2,500 or >1,000 in the case of resurfacings). Blue italics indicate that fewer than 100 cases remain at risk.
Stem/cup brand
No. of patients
Cumulative percentage probability of first revision (95% CI) at time shown if time since primary operation is:
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 yearsCemented:
Charnley Cemented Stem/ Charnley Ogee
9,0990.37
(0.26-0.52)0.85
(0.67-1.061.18
(0.97-1.44)1.46
(1.22-1.75)1.84
(1.56-2.17)2.16
(1.84-2.54)2.48
(2.12-2.91)2.92
(2.48-3.45)3.17
(2.66-3.78)
Charnley Cemented Stem/ Charnley Cemented Cup
10,3070.29
(0.20-0.41)0.58
(0.45-0.76)0.80
(0.64-1.01)1.03
(0.85-1.27)1.34
(1.12-1.61)1.64
(1.38-1.94)1.88
(1.59-2.23)2.33
(1.96-2.75)2.49
(2.09-2.96)
C-Stem Cemented/Elite Plus Ogee
3,7490.44
(0.27-0.73)0.70
(0.47-1.04)0.90
(0.63-1.29)1.07
(0.76-1.49)1.17
(0.84-1.62)1.28
(0.93-1.77)1.55
(1.11-2.16)1.97
(1.38-2.81)1.97
(1.38-2.81)
Stanmore Modular Stem/ Stanmore-Arcom Cup
4,1350.38
(0.23-0.63)0.58
(0.38-0.89)0.98
(0.69-1.38)1.10
(0.79-1.54)1.45
(1.05-1.98)1.61
(1.17-2.21)1.61
(1.17-2.21)1.61
(1.17-2.21)1.61
(1.17-2.21)
CPT/ZCA 8,2340.69
(0.53-0.90)0.94
(0.74-1.18)1.22
(0.99-1.51)1.50
(1.22-1.84)1.92
(1.58-2.33)2.31
(1.90-2.81)2.73
(2.22-3.36)2.88
(2.31-3.58)2.88
(2.31-3.58)Exeter V40/Contemporary
55,6560.43
(0.38-0.49)0.71
(0.63-0.78)0.93
(0.85-1.03)1.14
(1.04-1.26)1.39
(1.26-1.52)1.65
(1.51-1.82)1.84
(1.66-2.03)2.11
(1.88-2.37)2.30
(1.99-2.64)Exeter V40/Elite Plus Ogee
17,2610.29
(0.22-0.39)0.51
(0.41-0.63)0.74
(0.61-0.89)0.86
(0.72-1.03)1.04
(0.87-1.24)1.31
(1.11-1.56)1.50
(1.26-1.79)1.57
(1.30-1.90)1.57
(1.30-1.90)Exeter V40/Exeter Duration
13,7810.58
(0.47-0.73)0.91
(0.76-1.09)1.20
(1.02-1.42)1.51
(1.30-1.76)1.74
(1.51-2.01)2.12
(1.84-2.44)2.54
(2.22-2.94)3.07
(2.61-3.60)3.23
(2.73-3.82)
Exeter V40/ Elite Plus Cemented Cup
6,1240.43
(0.29-0.64)0.69
(0.50-0.95)0.88
(0.65-1.18)0.95
(0.71-1.28)0.99
(0.74-1.33)1.14
(0.83-1.56)1.33
(0.95-1.85)1.50
(1.03-2.16)1.50
(1.03-2.16)
Exeter V40/Exeter Rimfit
4,0240.67
(0.42-1.05)0.91
(0.55-1.51)- - - - - - -
C-Stem AMT Cemented Stem/ Elite Plus Cemented Cup
2,6580.44
(0.24-0.79)0.54
(0.31-0.92)0.75
(0.45-1.25)0.92
(0.57-1.49)1.12
(0.70-1.78)1.12
(0.70-1.78)- - -
Uncemented:
Accolade/Trident
16,9400.97
(0.83-1.13)1.62
(1.43-1.85)2.18
(1.94-2.46)2.60
(2.31-2.93)3.22
(2.83-3.67)3.55
(3.05-4.12)3.88
(3.12-4.81)3.88
(3.12-4.81)3.88
(3.12-4.81)Corail/Duraloc Cementless Cup
4,0230.72
(0.50-1.04)1.21
(0.92-1.61)1.66
(1.30-2.12)1.88
(1.49-2.37)2.28
(1.83-2.83)2.64
(2.13-3.27)3.11
(2.51-3.84)3.78
(3.02-4.73)4.66
(3.51-6.17)
Corail/Pinnacle 67,7240.82
(0.75-0.89)1.32
(1.23-1.42)1.86
(1.74-1.98)2.49
(2.34-2.65)3.14
(2.94-3.34)4.03
(3.75-4.33)4.89
(4.48-5.34)5.89
(5.11-6.79)8.07
(5.70-11.36)Corail/ASR Resurfacing Cup
2,5971.00
(0.68-1.47)3.29
(2.67-4.05)7.47
(6.52-8.56)14.25
(12.94-15.69)23.28
(21.56-25.12)33.82
(31.50-36.26)39.04
(36.12-42.10)43.30
(38.30-48.66)-
Furlong HAC Stem/CSF
14,8520.91
(0.77-1.08)1.30
(1.12-1.50)1.61
(1.42-1.84)1.85
(1.63-2.09)2.02
(1.79-2.27)2.27
(2.01-2.55)2.58
(2.29-2.91)2.89
(2.54-3.28)2.97
(2.59-3.40)
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Stem/cup brand
No. of patients
Cumulative percentage probability of first revision (95% CI) at time shown if time since primary operation is:
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 yearsFurlong HAC Stem/CSF Plus
11,3911.10
(0.92-1.31)1.54
(1.32-1.81)1.70
(1.46-1.99)1.87
(1.58-2.21)2.01
(1.63-2.47)2.01
(1.63-2.47)- - -
SL-Plus Cementless Stem/ EP/Fit Plus
4,1861.27
(0.97-1.67)2.22
(1.78-2.70)2.85
(2.37-3.43)3.37
(2.83-4.01)4.26
(3.59-5.04)4.69
(3.92-5.60)5.49
(4.45-6.76)5.75
(4.62-7.14)5.75
(4.62-7.14)
Taperloc Cementless Stem/Exceed ABT
9,8931.15
(0.95-1.39)1.44
(1.21-1.73)1.70
(1.42-2.04)1.93
(1.59-2.34)2.34
(1.85-2.96)2.72
(2.06-3.59)- - -
Hybrid:
CPT/Trilogy 8,9870.83
(0.66-1.05)1.11
(0.90-1.37)1.21
(0.99-1.49)1.62
(1.33-1.97)1.94
(1.60-2.35)2.26
(1.85-2.75)2.48
(2.01-3.04)2.63
(2.10-3.29)3.04
(2.19-4.21)Exeter V40/ Pinnacle
2,8030.48
(0.27-0.85)0.79
(0.50-1.26)1.02
(0.66-1.59)1.13
(0.73-1.75)1.29
(0.82-2.03)1.68
(0.95-2.98)1.68
(0.95-2.98)1.68
(0.95-2.98)-
Exeter V40/ Trident
28,3670.59
(0.51-0.69)0.90
(0.79-1.03)1.09
(0.96-1.24)1.25
(1.10-1.41)1.48
(1.30-1.67)1.73
(1.51-1.97)2.06
(1.75-2.42)2.31
(1.91-2.80)2.65
(1.96-3.58)Exeter V40/ Trilogy
10,3750.57
(0.44-0.73)0.80
(0.64-1.00)1.02
(0.83-1.25)1.20
(0.98-1.45)1.38
(1.13-1.67)1.64
(1.35-1.99)1.80
(1.47-2.20)2.12
(1.66-2.71)2.30
(1.75-3.01)
Reverse hybrid:
Corail/ Elite Plus Cemented Cup
2,5590.54
(0.31-0.93)0.93
(0.60-1.42)1.26
(0.85-1.86)1.52
(1.04-2.21)2.04
(1.36-3.04)2.04
(1.36-3.04)2.04
(1.36-3.04)2.04
(1.36-3.04)-
Corail/Marathon
3,1400.38
(0.20-0.70)0.65
(0.39-1.09)0.93
(0.57-1.53)0.93
(0.57-1.53)0.93
(0.57-1.53)- - - -
Resurfacing:
Adept Resurfacing Cup
3,2931.23
(0.90-1.67)1.85
(1.44-2.39)2.57
(2.06-3.20)3.54
(2.90-4.31)5.00
(4.13-6.03)6.67
(5.45-8.15)8.70
(6.91-10.93)8.70
(6.91-10.93)-
ASR Resurfacing Cup
3,0261.59
(1.20-2.10)3.44
(2.85-4.16)5.91
(5.12-6.81)9.44
(8.44-10.55)13.71
(12.48-15.05)18.57
(17.06-20.19)24.07
(22.18-26.11)29.69
(27.03-32.55)36.40
(30.94-42.48)
BHR Resurfacing Cup
18,2801.05
(0.92-1.21)1.66
(1.49-1.86)2.38
(2.17-2.62)3.15
(2.89-3.43)3.85
(3.56-4.17)4.69
(4.35-5.06)5.61
(5.21-6.04)6.61
(6.12-7.13)8.11
(7.40-8.88)
Cormet 2000 Resurfacing Cup
3,6291.44
(1.10-1.88)2.67
(2.19-3.25)3.55
(2.99-4.21)5.27
(4.57-6.07)7.39
(6.52-8.36)8.96
(7.96-10.08)11.41
(10.14-12.83)13.85
(12.23-15.65)16.34
(14.19-18.78)
Durom Resurfacing Cup
1,6601.40
(0.93-2.10)2.78
(2.08-3.70)3.83
(2.99-4.90)4.69
(3.74-5.87)5.89
(4.79-7.24)7.08
(5.80-8.63)9.45
(7.74-11.53)9.80
(7.99-12.01)9.80
(7.99-12.01)
Recap Magnum
1.6801.85
(1.31-2.63)2.77
(2.07-3.69)3.56
(2.75-4.60)4.36
(3.43-5.55)6.04
(4.78-7.62)7.43
(5.83-9.45)8.66
(6.51-11.49)8.66
(6.51-11.49)-
Conserve Plus Resurfacing Cup
1,3201.98
(1.35-2.89)3.62
(2.73-4.78)5.03
(3.96-6.38)6.83
(5.54-8.41)8.23
(6.74-10.02)10.12
(8.28-12.36)10.63
(8.59-13.11)12.22
(8.93-16.62)12.22
(8.93-16.62)
Table 3.11 (continued)
The cemented, uncemented and hybrid stem-cup brand sub-groups with more than 10,000 procedures in the preceding table (Table 3.11) have been further divided by bearing surface.
Table 3.12 shows the estimated cumulative percentage probabilities for the resulting fixation/bearing sub-groups in which there were more than 1,000 procedures.
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Table 3.12 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) at different times after the primary operation for cup-stem brand combinations with large group sizes (>10,000) with further subdivision by main bearing surface (provided the sub-group size >1,000). Blue italics indicate that fewer than 100 cases remain at risk.
Stem/cup brand
Bearing surface
No. of patients
Cumulative percentage probability of first revision (95% CI) at time shown if time since primary operation is:
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 yearsCemented:
Exeter V40/Contemporary
MoP 51,9120.42
(0.36-0.48)0.70
(0.63-0.78)0.92
(0.83-1.02)1.14
(1.03-1.25)1.39
(1.26-1.52)1.65
(1.49-1.82)1.83
(1.65-2.03)2.12
(1.88-2.40)2.33
(2.00-2.70)
CoP 3,2980.48
(0.29-0.80)0.68
(0.44-1.06)1.05
(0.71-1.54)1.18
(0.81-1.71)1.30
(0.88-1.92)1.63
(1.07-2.46)1.87
(1.20-2.90)1.87
(1.20-2.90)1.87
(1.20-2.90)Exeter V40/Elite Plus Ogee
MoP 16,0260.30
(0.23-0.40)0.50
(0.40-0.63)0.73
(0.60-0.90)0.85
(0.70-1.02)1.02
(0.85-1.22)1.27
(1.06-1.52)1.47
(1.22-1.77)1.55
(1.27-1.89)1.55
(1.27-1.89)
CoP 1,0420.21
(0.05-0.85)0.68
(0.31-1.51)0.96
(0.48-1.92)1.14
(0.59-2.20)1.41
(0.74-2.71)1.41
(0.74-2.71)1.41
(0.74-2.71)1.41
(0.74-2.71)1.41
(0.74-2.71)
Uncemented:
Accolade/Trident
MoP 8,2810.97
(0.77-1.21)1.56
(1.29-1.88)2.25
(1.89-2.66)2.71
(2.28-3.23)3.24
(2.63-3.98)3.39
(2.73-4.20)3.39
(2.73-4.20)3.39
(2.73-4.20)-
CoP 2,1710.85
(0.52-1.39)1.83
(1.25-2.67)2.22
(1.53-3.22)2.79
(1.86-4.20)3.43
(2.26-5.21)3.43
(2.26-5.21)3.43
(2.26-5.21)3.43
(2.26-5.21)3.43
(2.26-5.21)
CoC 6,3191.02
(0.80-1.31)1.69
(1.38-2.07)2.16
(1.79-2.60)2.49
(2.07-2.99)3.16
(2.61-3.83)3.60
(2.89-4.47)4.10
(3.02-5.57)4.10
(3.02-5.57)4.10
(3.02-5.57)Corail/Pinnacle
MoP 23,9490.86
(0.75-0.99)1.21
(1.07-1.37)1.47
(1.30-1.66)1.69
(1.50-1.92)1.82
(1.60-2.08)2.19
(1.89-2.55)2.41
(2.03-2.87)2.62
(2.10-3.29)2.62
(2.10-3.29)
MoM 11,7110.83
(0.68-1.01)1.55
(1.34-1.79)2.38
(2.12-2.68)3.51
(3.18-3.89)4.84
(4.41-5.32)6.51
(5.91-7.17)8.45
(7.52-9.50)11.10
(9.06-13.58)19.89
(11.37-33.48)
CoP 6,1340.65
(0.47-0.89)0.96
(0.72-1.28)1.25
(0.94-1.66)1.60
(1.19-2.14)1.84
(1.34-2.51)1.84
(1.34-2.51)1.84
(1.34-2.51)1.84
(1.34-2.51)-
CoC 23,4960.83
(0.72-0.96)1.37
(1.21-1.55)1.83
(1.63-2.05)2.26
(2.01-2.54)2.53
(2.23-2.86)2.91
(2.50-3.39)3.05
(2.57-3.62)3.05
(2.57-3.62)-
CoM 1,7420.46
(0.23-0.93)1.28
(0.83-1.95)2.86
(2.07-3.95)3.72
(2.64-5.22)5.06
(2.85-8.90)5.06
(2.85-8.90)5.06
(2.85-8.90)5.06
(2.85-8.90)-
Furlong HAC Stem/CSF
MoP 6,7290.98
(0.77-1.25)1.41
(1.14-1.73)1.82
(1.51-2.19)2.05
(1.71-2.44)2.23
(1.87-2.65)2.76
(2.32-3.27)2.91
(2.45-3.46)3.48
(2.84-4.26)3.48
(2.84-4.26)
CoP 6,2280.74
(0.55-0.98)1.07
(0.84-1.37)1.28
(1.02-1.60)1.53
(1.24-1.89)1.63
(1.33-2.00)1.68
(1.37-2.06)1.93
(1.57-2.37)1.99
(1.62-2.45)2.13
(1.69-2.68)
CoC 1,6081.25
(0.81-1.93)1.70
(1.17-2.47)2.03
(1.44-2.85)2.30
(1.66-3.18)2.59
(1.90-3.51)2.68
(1.98-3.63)3.70
(2.74-4.98)4.44
(3.25-6.06)4.44
(3.25-6.06)Furlong HAC Stem/CSF Plus
MoP 2,6261.35
(0.97-1.89)1.73
(1.27-2.35)1.87
(1.38-2.52)2.40
(1.70-3.40)3.02
(1.86-4.89)- - - -
CoP 1,2811.11
(0.64-1.91)1.58
(0.98-2.55)1.73
(1.08-2.76)1.73
(1.08-2.76)1.73
(1.08-2.76)- - - -
CoC 7,4221.00
(0.79-1.27)1.47
(1.20-1.81)1.65
(1.35-2.01)1.70
(1.39-2.09)1.70
(1.39-2.09)1.70
(1.39-2.09)- - -
Hybrid:
Exeter V40/ Trident
MoP 15,1130.64
(0.52-0.78)0.98
(0.82-1.17)1.18
(1.00-1.40)1.30
(1.10-1.54)1.50
(1.26-1.78)1.68
(1.39-2.04)2.18
(1.66-2.86)2.36
(1.76-3.17)2.36
(1.76-3.17)
CoP 3,3010.55
(0.33-0.89)0.77
(0.50-1.18)1.02
(0.68-1.52)1.02
(0.68-1.52)1.68
(1.00-2.80)1.68
(1.00-2.80)2.16
(1.19-3.90)2.16
(1.19-3.90)2.16
(1.19-3.90)
CoC 9,3750.53
(0.40-0.70)0.82
(0.65-1.04)0.99
(0.80-1.23)1.19
(0.97-1.47)1.42
(1.16-1.74)1.74
(1.41-2.14)1.98
(1.57-2.49)2.31
(1.74-3.07)2.89
(1.84-4.53)Exeter V40/ Trilogy
MoP 8,2100.54
(0.40-0.73)0.75
(0.58-0.97)0.96
(0.76-1.22)1.10
(0.88-1.39)1.33
(1.07-1.67)1.61
(1.28-2.01)1.75
(1.38-2.21)2.07
(1.54-2.76)2.07
(1.54-2.76)CoP 1,876 0.55
(0.29-1.01)0.79
(0.47-1.34)1.08
(0.68-1.72)1.42
(0.93-2.17)1.42
(0.93-2.17)1.69
(1.11-2.55)1.93
(1.24-2.98)2.32
(1.42-3.77)2.32
(1.42-3.77)
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3.2.5 Revisions after primary hip surgery: Effect of head sizes for polyethylene liners
Four sub-groups were identified with polyethylene liners,
i. metal-on-polyethylene monobloc-cup (n=185,027)
ii. (metal-on-polyethylene - metal shell with polyethylene liners (n=129,152)
iii. ceramic-on-polyethylene – polyethylene monobloc-cup (n=20,841)
iv. ceramic-on-polyethylene - metal shell with polyethylene liners (n=37,278)
The Graphs (i)-(iv) in Figure 3.5 show the respective cumulative hazards broken down by head size. The same scale has been used for all graphs to facilitate comparison between them. Only head sizes where there were more than 500 procedures are shown.
A Cox ‘proportional hazards’ regression analysis was performed to compare the head sizes in each case. The most frequently used head size, 28mm, was used as the baseline for comparison in each analysis.
In the case of (i), metal-on-polyethylene monobloc-cup, there were significant differences between the five head sizes shown (P<0.001). Rates of revision for 22.25mm head size did not differ significantly from the baseline of 28mm heads (Hazard rate ratio (HRR) 1.05 (95% CI 0.95-1.17) P=0.31). Revision rates for 26mm heads were significantly lower (0.80 (0.69-0.93) P=0.003) than for 28mm heads and rates for both 32mm and 36mm were higher (1.19 (1.02-1.40) P=0.031 & 2.08 (1.27-3.41) P=0.004, respectively).
For (ii) metal-on-polyethylene with metal shell/polyethylene liner, the differences between the head sizes were not significant overall (P=0.055), however the revision rates were higher for 44mm heads than the baseline 28mm heads (HRR 1.84, 95% CI 1.17-2.90, P=0.008) whereas other head sizes did not differ significantly (minimum P=0.14).
For the other groups, (iii) and (iv), there were no significant differences amongst the sets of head sizes shown (P=0.69, P=0.15, respectively), although there were too few cases for larger head sizes to make worthwhile comparisons.
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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Figure 3.5 (i) Comparison of the cumulative hazard for revision for different head sizes for metal-on-polyethylene monobloc cup. (NB only head sizes where n>500 are shown)
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8 9
Years since primary surger
Cum
ulat
ive
haza
rd x
100
y
Head size 22.5mm
Head size 26mm
Head size 28mm
29,582
16,642
120,152
16,784
1,331
27,420
15,416
103,028
11,586
746
25,021
14,049
86,715
7,925
393
22,410
12,742
71,059
5,258
165
19,585
10,951
55,970
3,317
30
16,573
8,990
40,629
2,056
3
13,107
6,943
26,182
1,172
0
9,701
4,945
15,606
639
0
5,922
2,772
7,224
291
0
2,312
965
2,260
78
0
Head size 32mm
Head size 36mm
Numbers at risk
© N
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146 www.njrcentre.org.uk
(ii) Comparison of the cumulative hazard for revision for different head sizes for metal-on-polyethylene with metal shell/polyethylene liners. (NB only head sizes where n>500 are shown)
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8 9
Years since primary surger
Cum
ulat
ive
haza
rd x
100
y
Head size 22.5mm
Head size 26mm
Head size 28mm
850
737
68,789
32,691
22,394
2,928
698
722
680
60,999
23,357
16,227
2,462
571
608
615
52,854
16,037
10,769
1,923
452
527
534
44,150
10,190
6,272
1,382
320
474
464
35,350
5,840
2,997
838
193
404
386
26,202
3,051
1,317
286
58
333
298
17,662
1,512
476
25
2
239
208
10,739
614
171
10
1
139
108
5,039
219
66
5
1
45
23
1,462
20
14
1
0
Head size 32mm
Head size 36mm
Head size 40mm
Head size 44mm
Numbers at risk
© N
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Figure 3.5
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
147www.njrcentre.org.uk
(iii) Comparison of the cumulative hazard for revision for different head sizes for ceramic-on-polyethylene with polyethylene monobloc cup. (NB only head sizes where n>500 are shown)
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8 9
Years since primary surger
Cum
ulat
ive
haza
rd x
100
y
Head size 22.25mm
Head size 28mm
Head size 32mm
2,314
15,115
3,073
2,082
12,558
2,074
1,814
10,310
1,339
1,599
8,134
829
1,376
6,259
447
1,104
4,506
210
801
3,040
120
485
1,958
62
190
1,032
23
0
364
9
Numbers at risk
© N
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Figure 3.5
148 www.njrcentre.org.uk
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8 9
Years since primary surger
Cum
ulat
ive
haza
rd x
100
y
Head size 28mm
Head size 32mm
Head size 36mm
18,790
11,265
6,883
16,743
8,077
4,229
14,724
5,591
2,657
12,686
3,497
1,524
10,569
2,096
711
8,443
1,184
313
6,161
725
120
4,125
406
21
2,199
151
0
748
37
0
Numbers at risk
© N
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(iv) Comparison of the cumulative hazard for revision for different head sizes for ceramic-on-polyethylene with metal shell/polyethylene liners. (NB only head sizes where n>500 are shown)
Figure 3.5
3.2.6 Mortality after primary hip surgery
This section describes the mortality of the cohort up to nine years from primary operation, according to gender and age group. Deaths were updated at the end of February 2013 using data from the Patient Demographic Service. Two hundred cases were excluded because the NHS number was not traceable and therefore no death date could be ascertained. A further three were excluded because of uncertainty in gender (n=1) and age (n=2), leaving 539,169, with a total of 42,805 reported deaths. Amongst these were 3,091 bilateral operations, with the left and right side operated on the same day; here the second of the two has been excluded, leaving 536,078 procedures and 42,655 deaths.
Table 3.13 shows Kaplan-Meier estimates of cumulative percentage mortality at 30 days, 90 days and at each anniversary up to the ninth, for all cases and by age and gender.
Note the cases were not ‘censored’ when further revision surgery was undertaken. Such surgery may have contributed to the overall mortality as shown here. The impact of this has not been quantified.
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© National Joint Registry 2013
Tab
le 3
.13
Kap
lan-
Mei
er e
stim
ates
of t
he c
umul
ativ
e pe
rcen
tage
mor
talit
y (9
5% C
I), a
t diff
eren
t tim
es a
fter
prim
ary
hip
oper
atio
n, fo
r al
l cas
es a
nd b
y ag
e/ge
nder
.
No
. of
pat
ient
s
Cum
ulat
ive
per
cent
age
pro
bab
ility
of
first
rev
isio
n (9
5% C
I) at
tim
e sh
ow
n if
time
sinc
e p
rim
ary
op
erat
ion
is:
30 d
ays
90 d
ays
1 ye
ar2
year
s3
year
s4
year
s5
year
s6
year
s7
year
s8
year
s9
year
sA
ll ca
ses
536,
078
0.25
(0.2
4-0.
260.
51(0
.50-
0.53
)1.
52(1
.49-
1.56
)3.
06(3
.01-
3.11
)4.
93(4
.86-
5.00
)7.
15(7
.06-
7.23
)9.
54(9
.43-
9.64
)12
.17
(12.
05-1
2.30
)14
.97
(14.
82-1
5.13
)18
.14
(17.
94-1
8.35
)21
.41
(21.
11-2
1.71
)
By
gen
der
and
ag
e g
roup
Mal
es:
<55
ye
ars
32,5
650.
08
(0.0
6-0.
12)
0.16
(0
.12-
0.21
)0.
49
(0.4
2-0.
57)
0.87
(0
.77-
0.98
)1.
28
(1.1
5-1.
43)
1.70
(1
.54-
1.87
)2.
08
(1.8
9-2.
28)
2.64
(2
.40-
2.89
)3.
23
(2.9
3-3.
55)
3.76
(3
.39-
4.17
)4.
39
(3.8
8-4.
96)
55-
59
year
s22
,505
0.05
(0
.03-
0.09
)0.
17
(0.1
2-0.
23)
0.57
(0
.48-
0.68
)1.
05
(0.9
2-1.
20)
1.78
(1
.60-
1.99
)2.
62
(2.3
8-2.
89)
3.19
(2
.91-
3.49
)3.
84
(3.5
1-4.
20)
4.78
(4
.37-
5.24
)5.
97
(5.4
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3.2.7 In-depth study: Metal-on-metal hip resurfacing
Since the last annual report we have examined metal-on-metal hip resurfacing in greater depth. A research paper comparing the failure rates of metal-on-metal hip resurfacings with alternative forms of hip replacement was published in the Lancet in November 2012.
Smith AJ, Dieppe P, Howard PW, Blom AW; National Joint Registry for England and Wales. Failure rates of metal-on-metal hip resurfacings: Analysis of data from the National Joint Registry for England and Wales. Lancet. 2012 Nov 17;380(9855):1759-66
We have analysed data from the NJR to test the following hypotheses: larger head size is related to higher failure rates; metal-on-metal has significantly worse results in women; and hip resurfacing gives better implant survivorship than stemmed THR in younger patients.
Methods
Analysis was based on 434,560 THRs between April 2003 and September 2011 where patient-identifiers are present that allow revisions to be linked to primary operations (81.8% of 531,247 operations). These operations were performed in 447 units under the care of 2,584 consultant surgeons.
The analysis estimated all-cause revision rates. The unit of analysis was implant (rather than patient) so bilateral procedures were included (2,645). We have compared revision rates for three types of bearing surface: resurfacing, ceramic-on-ceramic, and metal-on-polyethylene. A range of commonly used head sizes were compared for the resurfacing and ceramic-on-ceramic groups whereas the most commonly used head size of 28mm (Table 1) was been chosen for the metal-on-polyethylene group. A confounding variable was the fixation of the implant. We have addressed this by reporting ceramic-on-ceramic results for uncemented fixation as this was most commonly used (45,099/57,748, 78.1%) while for metal-on-polyethylene, results were shown separately for cemented, uncemented and hybrid fixations.
There were substantial differences between the bearing groups in terms of patient characteristics. To reduce the effects of confounding, analysis was based on the large majority with an American Society of Anaesthesiologists (ASA) grade of 1 or 2 at time of primary surgery and those whose surgery was undertaken for osteoarthritis only (Table 1). The now-withdrawn ASR implants (2,829, 8.9% of the total) were excluded from the resurfacing analysis so as not to distort the results. Furthermore, sensitivity analysis confirmed that the results for the newer technologies of resurfacing and ceramic-on-ceramic were not distorted by a ‘learning curve’ effect of less experienced surgeons (see web appendix published in Lancet).
Multivariable analysis has been used to adjust for patient age and ASA grade and to measure the effect of head size. As head size and gender were highly correlated, separate models were estimated for men and women to avoid multicollinearity. Separate models were also specified for the different bearing groups.
Flexible parametric survival models that estimate the cumulative incidence of revision in the presence of the competing risk of death were used. Standard survival analysis treats death simply as censored information but this has been shown to overestimate revision rates. In all models, head size, age and ASA grade were selected as predictors of revision and age and ASA grade were predictors of the competing risk of death. The effect of age was allowed to differ for the main and competing risks. These models produce hazard ratios, which are a measure of relative risk (averaged over time). To illustrate the absolute effect of these factors, the models have been used to predict revision rates for a typical patient by estimating the covariate-adjusted cumulative incidence function in the presence of competing risks.
One resurfacing brand, the Birmingham Hip Resurfacing system (BHR), was used in more than half of cases giving large enough numbers to repeat the multivariable analysis approach for the BHR cases alone (15,386/26,199, 58.9%). This enabled the potentially confounding influence of different brand effects to be removed. We have compared the BHR with the most commonly used alternatives in each group: the Exeter V40 Contemporary metal-on-
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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polyethylene 28mm cemented THR (23,906/69,569, 34.4%) and the Corail Pinnacle 36mm ceramic-on-ceramic uncemented THR (9,604/18,370, 52.3%).
The reasons for revision across all groups were also examined by dividing the number of revisions for each reason by the total person time at risk of revision (per 1,000 patient-years). This was equivalent to a person-time incidence rate and 95% confidence intervals have been estimated assuming a Poisson distribution.
Results
Overall, 7.4% (31,932/434,560) of THRs were resurfacing procedures. Annual numbers in England and Wales reached a peak of 6,650 operations in 2007 but thereafter fell to around 2,000 in 2011. Resurfacing patients were most commonly aged 59 years while the median age was 55. Overall, 78.4% of patients were aged 45-65 years and 69.1% of resurfacings were undertaken on men (Table L1).
Unadjusted analysis suggested that revision rates for resurfacing procedures were higher than for stemmed THR (five-year revision rate of 5.2% (95% CI 4.9-5.5%) compared with 2.8% (95% CI 2.7-2.9%). However, this overall rate disguised differences according to gender (Figure L1). In women, 8.5% of resurfacings had been revised by five years (95% CI 7.8-9.2%) compared with 3.6% in men (95% CI 3.3-3.9%). A head size of between 46mm and 54mm was used for 92.1% (20342/22076) of male resurfacing patients while 76.5% (7541/9856) of females had a head size of 42-46mm. Just 1% (98/9,856) of women received the larger head sizes above 50mm. In total, 15 resurfacing brands were used.
The multivariable models for resurfacing procedures confirmed that head size was an independent predictor of revision for both men (hazard ratio 0.951, 95% CI 0.945-0.978, p<0.0005 per unit increase in head size) and women (hazard ratio 0.921, 95% CI 0.892-0.951, p<0.0005) indicating that smaller head sizes were more likely to be revised. These hazard ratios can be broadly interpreted as each 1mm increase in head size being associated with a 5-8% reduction in the hazard (the risk of revision at a particular point in time). Age was a significant predictor
of the competing risk of death but not of revision for either men or women. ASA grade was a significant predictor of revision for men only (hazard ratio 1.267, 95% CI 1.042-1.540, p=0.018) indicating that patients with ASA grade 2 were more likely to be revised than those with ASA grade 1.
Predicted revision rates from these models illustrate the absolute effect of head size. For a 55-year-old man, the five-year revision rate with a 46mm head was 4.1% compared with 2.6% for a 54mm head (Table L2). Resurfacing revision rates for women were much higher than for men (five-year revision rate of 8.3% with a 42mm head size) (Table L3). This was true even with the same head size: a 55-year-old woman had a five-year revision rate of 6.1% with a 46mm head size compared with 4.1% for a 55-year-old man. Only 0.4% (35/9,856) of women had a head size of 54mm or above associated with the lowest revision rates in men.
Resurfacing procedures with a large head size (54mm or greater) resulted in revision rates which were not significantly worse than those of other common surgical options (Table L2). In men, a 54mm resurfacing head had a five-year revision rate of 2.6% compared with 2.1% for an uncemented 40mm ceramic-on-ceramic prosthesis and 1.9% for a cemented 28mm metal-on-polyethylene articulation. However, the smaller resurfacing head sizes compared less well. Key results are illustrated in Figure L2. Overall, just 23% (5,085/22,076) of male resurfacings used the 54mm or larger head size that had the lowest revision rates.
In women, resurfacing, even with larger heads, offered significantly poorer implant survivorship than all other common surgical options (Table L3). In 55-year-old women, a 46mm resurfacing procedure had a fiveyear revision rate of 6.1% compared with 2.5% for a 36mm ceramic-on-ceramic prosthesis and 1.5% for a cemented 28mm metal-on-polyethylene articulation (Figure L3).
Generally, the BHR had better implant survivorship than other resurfacing brands. Unadjusted analysis for all male patients shows a five-year revision rate of 2.4% (95% CI 2.1-2.7%) for the BHR compared with 8.1% (95% CI 6.7-9.8%) for the now-withdrawn ASR
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Figure L1 Cumulative hazard of revision after resurfacing by gender (with 95% CI).
Years since primary surgery
Female
Male
2%
4%
6%
8%
10%
12%
14%
0 1 2 3 4 5 6 7
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and 4.2% (95% CI 3.7-4.9%) for other resurfacing brands. The equivalent five-year revision rates in women were more than twice as high for all brands (5.8% (95% CI 5.1-6.6%) for the BHR, 21.0% (95% CI 17.7-24.9%) for the ASR and 9.2% (95% CI 8.1-10.5%) for other brands). However, the multivariable models indicated that in men aged 55, the BHR with the 54mm head size did not demonstrate better implant survivorship than the Exeter/Contemporary or the Corail/Pinnacle and had considerably worse implant survivorship in women (Table L4).
Resurfacings were most commonly revised for pain, periprosthetic fracture, and aseptic loosening (Table L5). Revision for periprosthetic fracture was up to eight times more common in resurfacing than in other surgical options. Revisions for pain in women were up to 10 times higher with resurfacing than with other surgical options and revisions for aseptic loosening were up to four times higher. Revisions for dislocation in resurfacing were lower than other options in men.
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Figure L2 Estimated cumulative incidence of revision for 55-year-old male by prosthesis type.
Figure L3 Estimated cumulative incidence of revision for 55-year-old female by prosthesis type.
Years since primary surgery
Resurfacing 46mm
Resurfacing 52mm
Resurfacing 48mm
Resurfacing 50mm
Resurfacing 54mm
Uncemented ceramic-on-ceramic 40mm
Cemented metal-on-polyethylene 28mm0
1%
2%
3%
4%
5%
Cum
ulat
ive
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ce o
f rev
isio
n
0 1 2 3 4 5 6 7
Years since primary surgery
Resurfacing 42mm
Uncemented ceramic-on-ceramic 36mm
Resurfacing 44mm
Resurfacing 46mm
Cemented metal-on-polyethylene 28mm0
1%2%3%4%5%6%7%8%9%
10%11%12%
Cum
ulat
ive
inci
denc
e of
rev
isio
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0 1 2 3 4 5 6 7
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Table L1 Description of comparison groups: number of cases (percentage of total).
Bearing surface
Resurfacing (N=31,932)Ceramic-on-ceramic
(N=57,748) Metal-on-polyethylene
(N=226,165)Head sizeLess than 28mm 0 (0.0%) 0 (0.0%) 22,140 (9.9%)28mm 0 (0.0%) 12,274 (21.3%) 154,305 (68.2%)30-34mm 0 (0.0%) 18,680 (32.3% 30,059 (13.3%)36-40mm 577 (1.8%) 26,339 (46.0%) 16,113 (7.2%)42mm 2,107 (6.6%) 0 (0.0%) 0 (0.0%)44mm 2,032 (6.4%) 0 (0.0%) 349 (0.2%)46mm 5,626 (17.6%) 0 (0.0%) 0 (0.0%)48mm 3,735 (11.7%) 0 (0.0%) 0 (0.0%)50mm 8,905 (27.9%) 0 (0.0%) 0 (0.0%)52mm 3,397 (10.6%) 0 (0.0%) 0 (0.0%)54mm 4,054 (12.7%) 0 (0.0%) 0 (0.0%)56-62mm 1,066 (3.3%) 0 (0.0%) 0 (0.0%)Unknown size 379 (1.2%) 455 (0.8%) 3,199 (1.4%)Age (mean age in years) 54.1 59.6 72.7Aged less than 40 years 1,934 (6.1%) 2,874 (5.0%) 558 (0.3%)Aged 40-49 6,877 (21.5%) 6,065 (10.5%) 1,929 (0.9%)Aged 50-59 14,067 (44.1%) 16,877 (29.2%) 12,451 (5.5%)Aged 60-69 8,229 (25.8%) 22,918 (39.7%) 58,865 (26.0%)Aged 70 or over 825 (2.6%) 9,014 (15.6%) 152,362 (67.4%)GenderMale 22,076 (69.1%) 25,290 (43.8%) 78,891 (34.9%)Female 9,856 (30.9%) 32,458 (56.2%) 147,274 (65.1%)ASA grade1 - fit and healthy 15,613 (48.9%) 16,048 (27.8%) 29,320 (13.0%)2 - mild systemic disease that does not limit activity
15,336 (48.0%) 37,196 (64.4%) 157,492 (69.6%)
3 - systemic disease that limits activity but is not incapacitating
947 (3.0%) 4,385 (7.6%) 37,764 (16.7%)
4/5 - incapacitating, life-threatening systemic disease/not expected to survive 24 hours without an operation
36 (0.1%) 119 (0.2%) 1589 (0.7%)
DiagnosisOsteoarthritis only 29,550 (92.5%) 50,626 (87.7%) 208,173 (92.0%)Other 2,382 (7.5%) 7,122 (12.3%) 17,992 (8.0%)Total (% of all THR) 31,932 (7.4%) 57,748 (13.3%) 226,165 (52.0%)Multivariable model samplesTotal in model 26,119 (81.8%) 36,009 (62.4%) 115,574 (51.1%)Number of surgeons 698 (27.0%) 1,202 (46.5%) 2,144 (83.0%)Number of units 372 (83.2%) 397 (88.8%) 434 (97.1%)Numbers followed up by yearLess than 1 year 1,681 (6.4%) 9,034 (25.1%) 14,871 (12.9%)1 - < 2 years 2,692 (10.3%) 8,868 (24.6%) 16,967 (14.7%)2 - < 3 years 3,708 (14.2%) 6,419 (17.8%) 17,257 (14.9%)3 - < 4 years 4,457 (17.1%) 4,577 (12.7%) 17,852 (15.4%)4 - < 5 years 4,335 (16.6%) 2,940 (8.2%) 16,906 (14.6%)5 - < 6 years 3,653 (14.0%) 1,980 (5.5%) 13,218 (11.4%)6 - < 7 years 2,835 (10.9%) 1,182 (3.3%) 10,265 (8.9%)7 or more years 2,756 (10.6%) 1,008 (2.8%) 8,237 (7.1%)
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Note: among the full sample of hip replacements (N=434,560), there are other bearing surfaces which are not shown in this table: 46,290 ceramic-on-polyethylene (10.7% of the total), 31,171 stemmed metal-on-metal (7.2% of total), 2,430 other combinations (0.6%), and 38,824 unknown bearings (8.9%).
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Table L2 Predicted revision rates for 55-year-old males by prosthesis and head size (95% CI).
Type/head size Year 1 Year 3 Year 5 Year 7
Resurfacing 46mm 1.57 (1.26-1.95) 2.81 (2.31-3.42) 4.05 (3.34-4.90) 5.23 (4.29-6.38)
48mm 1.40 (1.17-1.68) 2.52 (2.15-2.94) 3.63 (3.12-4.21) 4.69 (3.99-5.51)
50mm 1.26 (1.06-1.48) 2.25 (1.96-2.58) 3.25 (2.85-3.70) 4.20 (3.65-4.84)
52mm 1.12 (0.94-1.34) 2.02 (1.74-2.34) 2.91 (2.52-3.35) 3.77 (3.23-4.38)
54mm 1.00 (0.82-1.23) 1.80 (1.50-2.17) 2.60 (2.18-3.11) 3.37 (2.80-4.06)
Ceramic-on-ceramic
Uncemented 28mm 1.24 (0.92-1.68) 2.46 (1.87-3.22) 3.41 (2.64-4.40) 4.08 (3.14-5.28)
Uncemented 32mm 1.05 (0.84-1.30) 2.07 (1.72-2.50) 2.88 (2.39-3.47) 3.45 (2.81-4.23)
Uncemented 36mm 0.88 (0.71-1.10) 1.75 (1.43-2.14) 2.43 (1.96-3.02) 2.91 (2.28-3.71)
Uncemented 40mm 0.74 (0.55-1.01) 1.48 (1.09-2.00) 2.05 (1.49-2.83) 2.46 (1.73-3.47)
Metal-on-polyethylene
Cemented 28mm 0.56 (0.43-0.73) 1.28 (1.00-1.64) 1.91 (1.50-2.44) 2.40 (1.87-3.06)
Hybrid 28mm 1.26 (0.83-1.92) 2.19 (1.48-3.24) 3.21 (2.20-4.67) 4.10 (2.80-5.97)
Uncemented 28mm 1.41 (1.03-1.93) 2.57 (1.92-3.42) 3.48 (2.63-4.59) 4.18 (3.14-5.56)
Table L3 Predicted revision rates for 55-year-old females by prosthesis and head size (95% CI).
Type/head size Year 1 Year 3 Year 5 Year 7
Resurfacing 42mm 1.81 (1.47-2.24) 5.09 (4.33-5.97) 8.33 (7.18-9.65) 11.67 (10.00-13.58)
44mm 1.54 (1.26-1.88) 4.33 (3.75-4.99) 7.11 (6.24-8.09) 9.99 (8.71-11.43)
46mm 1.31 (1.07-1.60) 3.69 (3.17-4.28) 6.07 (5.28-6.95) 8.54 (7.39-9.85)
Ceramic-on-ceramic
Uncemented 28mm 0.87 (0.68-1.12) 1.87 (1.50-2.33) 2.63 (2.12-3.25) 3.31 (2.63-4.17)
Uncemented 32mm 0.84 (0.69-1.01) 1.81 (1.53-2.13) 2.54 (2.15-3.01) 3.20 (2.62-3.92)
Uncemented 36mm 0.81 (0.65-1.02) 1.75 (1.41-2.17) 2.46 (1.95-3.09) 3.10 (2.38-4.03)
Metal-on-polyethylene
Cemented 28mm 0.60 (0.32-1.10) 1.12 (0.62-2.01) 1.47 (0.82-2.60) 1.81 (0.99-3.28)
Hybrid 28mm 0.70 (0.49-1.02) 1.23 (0.87-1.73) 1.82 (1.30-2.53) 2.48 (1.77-3.47)
Uncemented 28mm 0.81 (0.60-1.07) 1.46 (1.12-1.91) 1.94 (1.49-2.53) 2.25 (1.71-2.95)
Note: results are estimated from multivariable competing risks flexible parametric survival models based on 18,375 resurfacing cases, 16,136 uncemented ceramic-on-ceramic cases, and for 28mm metal-on-polyethylene: 22,407 cemented, 6,634 hybrid and 9,352 uncemented cases. Results are based on an ASA grade of 2.
Note: results are estimated from multivariable competing risks flexible parametric survival models based on 7,744 resurfacing cases, 19,873 uncemented ceramic-on-ceramic cases, and for 28mm metal-on-polyethylene: 47,162 cemented, 13,383 hybrid and 16,636 uncemented cases. Results are based on an ASA grade of 2.
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Table L4 Comparison of most commonly used brands; predicted revision rates for 55-year old patients (95% CI).
Type/head size Year 1 Year 3 Year 5 Year 7
Males aged 55 BHR 46mm 1.52 (1.12-2.05) 2.48 (1.87-3.28) 3.43 (2.61-4.50) 4.32 (3.26-5.70)
BHR 50mm 1.15 (0.92-1.43) 1.87 (1.54-2.28) 2.60 (2.15-3.12) 3.27 (2.69-3.97)
BHR 54mm 0.86 (0.65-1.15) 1.41 (1.09-1.84) 1.96 (1.52-2.52) 2.47 (1.90-3.20)Uncemented Corail /Pinnacle ceramic-on-ceramic 36mm
0.93 (0.65-1.35) 1.90 (1.36-2.64) 2.52 (1.72-3.67) -
Cemented Exeter V40/ Contemporary metal-on-polyethylene 28mm
0.53 (0.28-1.02) 1.00 (0.54-1.86) 1.31 (0.71-2.41) 1.61 (0.86-3.02)
Females aged 55
BHR 42mm 2.01 (1.52-2.66) 5.02 (4.03-6.25) 8.23 (6.73-10.04) 11.76 (9.59-14.36)
BHR 46mm 1.20 (0.91-1.57) 3.00 (2.43-3.71) 4.96 (4.08-6.00) 7.14 (5.86-8.67)Uncemented Corail/Pinnacle ceramic-on-ceramic 36mm
0.63 (0.42-0.94) 1.53 (1.07-2.20) 2.00 (1.35-2.95) -
Cemented Exeter V40/ Contemporary metal-on-polyethylene 28mm
0.42 (0.25-0.71) 0.87 (0.54-1.41) 1.38 (0.86-2.20) 1.94 (1.18-3.17)
Note: results are estimated from multivariable competing risks flexible parametric survival models based on 10,889 male and 4,497 female BHR resurfacing cases, 5,389 male and 4,213 female Corail Pinnacle 36mm ceramic-on-ceramic cases and 7,857 male and 16,049 female cases for the Exeter/Contemporary. Results are based on an ASA grade of 2. Seven-year revision rates cannot be estimated for the Corail/Pinnacle ceramic-on-ceramic 36mm as this has only been in use in England and Wales since 2005.
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Table L5 Reasons for revision (95% CI), expressed as incidence per 1,000 patient-years, by articulation and fixation.
Resurfacing
Uncemented ceramic-on-
ceramic
Uncemented metal-on-
polyethylene 28mm
Hybrid11 metal-on-polyethylene
28mm
Cemented metal-on-polyethylene
28mm
Males Aseptic loosening 1.42 (1.17-1.72) 1.80 (1.42-2.27) 1.88 (1.48-2.41) 0.73 (0.47-1.14) 0.75 (0.58-0.97)
Dislocation/subluxation 0.18 (0.10-0.31) 1.13 (0.84-1.52) 1.56 (1.19-2.04) 1.77 (1.32-2.36) 0.75 (0.58-0.97)
Implant failure 0.07 (0.03-0.16) 0.46 (0.29-0.73) 0.35 (0.20-0.62) 0.12 (0.04-0.37) 0.10 (0.05-0.20)
Implant fracture 0.29 (0.19-0.44) 0.62 (0.41-0.92) 0.03 (0.00-0.21) 0.15 (0.06-0.41) 0.05 (0.02-0.13)
Incorrect sizing 0.03 (0.01-0.11) 0.05 (0.01-0.21) 0.03 (0.00-0.21) 0.00 - 0.00 -
Infection 0.55 (0.40-0.75) 1.13 (0.84-1.52) 1.12 (0.81-1.54) 1.15 (0.80-1.65) 1.09 (0.88-1.34)
Lysis 0.25 (0.16-0.39) 0.08 (0.02-0.24) 0.29 (0.16-0.55) 0.19 (0.08-0.46) 0.24 (0.15-0.37)
Malalignment 0.64 (0.48-0.86) 0.59 (0.39-0.89) 0.68 (0.45-1.02) 0.27 (0.13-0.56) 0.21 (0.13-0.34)
Other 1.12 (0.90-1.39) 0.69 (0.48-1.01) 0.18 (0.08-0.39) 0.31 (0.15-0.61) 0.15 (0.09-0.26)
Pain 1.70 (1.42-2.02) 1.13 (0.84-1.52) 1.00 (0.72-1.40) 0.77 (0.50-1.19) 0.46 (0.34-0.64)
Periprosthetic fracture 1.54 (1.28-1.86) 0.64 (0.43-0.95) 0.38 (0.22-0.66) 0.69 (0.44-1.10) 0.51 (0.38-0.70)
Person time (years) 73,143.3 38,917.4 33,959.7 26,061.9 79,971.8
Number revised 457 255 185 128 267
Number of operations 18,375 16,136 9,352 6,634 22,407
Females
Aseptic loosening 3.73 (3.14-4.43) 1.25 (0.97-1.61) 1.17 (0.92-1.49) 0.83 (0.61-1.12) 0.75 (0.63-0.90)
Dislocation/subluxation 0.77 (0.53-1.13) 1.09 (0.83-1.42) 1.72 (1.41-2.10) 1.38 (1.09-1.75) 0.81 (0.69-0.96)
Implant failure 0.37 (0.22-0.64) 0.41 (0.26-0.64) 0.21 (0.12-0.38) 0.28 (0.16-0.47) 0.05 (0.03-0.10)
Implant fracture 0.32 (0.17-0.57) 0.66 (0.46-0.93) 0.05 (0.02-0.17) 0.06 (0.02-0.18) 0.03 (0.01-0.07)
Incorrect sizing 0.09 (0.03-0.27) 0.12 (0.06-0.27) 0.05 (0.02-0.17) 0.02 (0.00-0.14) 0.01 (0.00-0.05)
Infection 0.63 (0.42-0.96) 0.41 (0.26-0.64) 0.39 (0.26-0.59) 0.32 (0.19-0.52) 0.56 (0.46-0.69)
Lysis 0.86 (0.60-1.23) 0.12 (0.06-0.27) 0.07 (0.03-0.19) 0.18 (0.09-0.34) 0.14 (0.10-0.21)
Malalignment 1.15 (0.84-1.56) 0.78 (0.57-1.07) 0.82 (0.61-1.09) 0.47 (0.32-0.71) 0.30 (0.23-0.39)
Other 2.78 (2.28-3.40) 0.74 (0.53-1.02) 0.41 (0.27-0.62) 0.18 (0.09-0.34) 0.17 (0.12-0.25)
Pain 5.28 (4.57-6.10) 1.00 (0.76-1.33) 0.68 (0.49-0.93) 0.51 (0.35-0.75) 0.41 (0.33-0.52)
Periprosthetic fracture 1.61 (1.24-2.09) 0.94 (0.71-1.26) 0.55 (0.39-0.78) 0.32 (0.19-0.52) 0.19 (0.14-0.27)
Person time (years) 34,859.4 48,806.1 56,259.4 50,637.5 167,174.5
Number revised 477 274 248 167 411
Number of operations 7,744 19,873 16,636 13,383 47,162
11 Not including reverse hybrid
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3.2.8 Conclusions
This year’s report confirms many of the trends shown in previous years. Once again we stress that implant survivorship alone is an incomplete measure of outcome. Implant survivorship gives little indication of satisfaction, relief of pain, improvement in function and greater participation in society. Readers should also understand that each year more data are available and thus analysis can give a more accurate picture. Each year’s analysis thus supersedes the previous analyses and may, in places, appear contradictory with previous reports from a smaller dataset. Furthermore, the data are imperfect and rely on accurate and comprehensive reporting by surgeons. Some fields, such as body mass index (BMI), were not initially reported but we are encouraged that in 2012 over 60% of entries included BMI data. We would urge surgeons to complete all fields in the NJR forms in order to allow meaningful analysis. This year we have analysed survivorship for metal-on-polyethylene bearings by head size for the first time. We have not attempted to sub-classify polyethylene as what constitutes so called third generation polyethylene is not clearly defined. This analysis shows that there appears to be an association between increased implant failure and larger head sizes.
We note that metal-on-metal stemmed hip replacement and hip resurfacing have virtually ceased with fewer than one in one thousand hip replacements performed in 2012 belonging to each of these classes of implant. The failure rates in these classes continue to be markedly higher than the alternatives. Other bearing surfaces continue to have very low failure rates regardless of fixation, especially for ceramic-on-polyethylene bearings.
As we now have more data, we have been able to extend brand analysis to more stem/cup combinations. Brand analysis of stem/cup combinations shows higher unadjusted failure rates with uncemented stem/cup combinations than with hybrid or all cemented combinations. The best survivorship at nine years is achieved with all-cemented components.
The in-depth analysis of hip resurfacing highlights the high failure rate, particularly amongst women. It also demonstrates that failure rate is related to both gender and head size, with smaller femoral heads and female gender independently associated with higher rates of implant revision. In men with the largest head sizes the failure rates are not significantly worse than alternatives. Only 23% of men who have undergone resurfacing in England and Wales have these larger femoral heads.
Mortality in the first 30 or 90 days after surgery remains very low, which is reassuring. However, mortality at nine years after hip replacement is high in those over the age of 75 suggesting than long-term implant survivorship is unlikely to be important in this age group.
Part 33.3 Outcomes after primary knee replacement
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In the period 2003 to 2012 589,028 knees were replaced for the first time. The knee is made up of three compartments: medial, lateral and patello femoral compartments; when a ‘total’ knee replacement (TKR) is implanted two out of the three compartments are always replaced (medial and lateral) and the patella is resurfaced if the surgeon considers this to be of benefit to the patient. If a single compartment is replaced then the term ‘unicompartmental’ is applied to the implant (UKR). The medial, lateral or patello-femoral compartments can be replaced independently, if clinically appropriate.
There is variation in the constraint of the tibial insert depending on whether the posterior cruciate ligament is preserved (cruciate retaining CR) or sacrificed (posterior-stabilised, PS) at the time of surgery. Additional constraint may be necessary to allow the
implant to deal with additional ligament deficiency or bone loss, where a constrained condylar (CCK) or hinged knee would be used, even in a primary situation. The tibial construct may be modular with a metallic tibial tray and a polyethylene insert or non-modular being constructed of polyethylene alone. In recent years all-polyethylene tibial components have increased in popularity so as to contain costs of the implant.
The tibial insert may be mobile or remain in a fixed position on the tibial tray. This also applies to medial and lateral unicompartmental knees. Many brands of total knee implant exist in fixed and mobile forms with CR or PS constraint.
The method of fixation used to secure the vast majority of knee replacements in place is cement (83.4% from table 3.14), unlike hip replacements.
Terminology note
Both total and partial knee replacement procedures are discussed in this section. At present, the NJR does not distinguish between medial and lateral unicondylar knee replacements during the data collection process. In addition, there are other possible knee designs, such as combinations of unicondylar and patello-femoral
replacements, but these are not reported on here as numbers are too small.
With regard to the use of the phrase ‘constraint’ here, for brevity, total knee replacements are termed unconstrained (instead of posterior cruciate-retaining) or posterior-stabilised (instead of posterior cruciate-stabilised).
3.3.1 Overview of primary knee surgery
Table 3.14 shows the proportion of all kinds of primary knee operations performed, broken down by fixation method and bearing type. The vast majority of replacements were of the total knee joint with an all cemented implant being the most common fixation method used (83.4% of all primary knee operations were total replacements using all cemented components). Nearly 9% of all primary operations were unicondylar and, of the remaining total knee replaced joints, 6.5% were either all uncemented or a hybrid type (made up of both cemented and uncemented parts).
Over half of all operations (54%) were total knee replacements which were all cemented, unconstrained and fixed, followed by 21% which were all cemented,
posterior-stabilised and fixed. A number of primary operations could not be classified according to their bearing/constraint (approximately 2.5%).
Table 3.15 shows the annual change in usage of primary knee replacement. Overall, over 80% of all primaries utilised an all cemented fixation method and, since 2003, the share of all implant replacements of this type has increased by some 5%. The main decline in type of primary surgery has been in the use of all uncemented and hybrid total knee replacements over time. Each approximately has halved in terms of proportion of implants of this type now used compared to figures for 2003. There has also been a steady increase in use of all cemented all polyethylene tibial implants (2.1% of primary surgeries in 2012 compared to less than half a percent of all primary surgeries between 2003 and 2005).
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Table 3.14 Numbers and percentages of primary knee replacements by fixation method and bearing type.
Type of primary knee operation Number of primary knee operations Percentage of totalFixation method Bearing Type
Total knee replacement
All cemented 490,939 83.4
Cemented and
unconstrained, fixed 317,914 54.0
unconstrained, mobile 25,931 4.4
posterior-stabilised, fixed 123,162 20.9
posterior-stabilised, mobile 8,276 1.4
constrained condylar 2,173 0.4
all polyethylene tibia 6,124 1.0
bearing type unknown 7,359 1.3
All uncemented 31,382 5.3
All hybrid 7,307 1.2
Uncemented/hybrid and
unconstrained, fixed 18,865 3.2
unconstrained, mobile 16,502 2.8
posterior stabilised, fixed 2,479 0.4
other constraint 350 0.06
bearing type unknown 493 0.08
Unicompartmental knee replacement
All unicondylar 51,474 8.7
Unicondylar and
fixed 13,763 2.3
mobile 36,982 6.3
bearing type unknown 729 0.1
All patello-femoral 7,881 1.3
Knee type unknown 45 0.01
All types 589,028 100.0©
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Table 3.15 Percentage of primary knee replacements performed each year by method of fixation and, within each fixation group, by bearing type.
Percentage of knee replacements each year by fixation and bearing type
2003 2004 2005 2006 2007 2008 2009 2010 2011 2012Total knee replacement
All cemented 81.5 80.8 81.7 81.4 81.9 81.9 82.7 84.0 85.6 86.9
Cemented and
unconstrained, fixed 53.3 53.0 53.0 50.7 50.5 51.4 53.1 54.5 56.6 59.8unconstrained, mobile
4.0 4.2 5.2 6.3 6.3 5.6 4.6 3.9 2.8 2.3
posterior-stabilised, fixed
20.8 20.6 19.8 20.1 20.4 21.0 21.4 21.7 21.6 20.6
posterior-stabilised, mobile
0.9 1.1 1.6 1.9 1.7 1.4 1.4 1.4 1.2 1.1
constrained condylar 0.4 0.5 0.4 0.3 0.3 0.3 0.3 0.4 0.4 0.5
all polyethylene tibia 0.3 0.2 0.4 0.6 0.9 0.9 0.7 1.0 1.7 2.1bearing type unknown
1.8 1.3 1.4 1.6 1.8 1.4 1.2 1.1 1.2 0.6
All uncemented 6.7 6.6 6.2 6.5 6.5 6.2 5.7 4.7 4.1 3.3
All hybrid 2.8 2.8 2.4 1.7 1.4 1.4 1.2 0.9 0.5 0.4
Uncemented/hybrid and
unconstrained, fixed 4.9 4.7 4.3 4.0 4.1 4.0 3.7 2.7 1.9 1.4
unconstrained, mobile 3.5 3.7 3.3 3.2 3.1 3.1 2.7 2.6 2.4 2.1posterior stabilised, fixed
0.9 0.7 0.6 0.7 0.5 0.4 0.4 0.3 0.2 0.2
other constraint 0.0 0.0 0.2 0.2 0.1 0.1 0.0 0.0 0.0 0.0bearing type unknown
0.3 0.3 0.2 0.2 0.1 0.1 0.1 0.0 0.0 0.0
Unicompartmental knee replacement
All unicondylar 8.0 8.7 8.6 9.2 8.8 9.1 9.0 9.0 8.4 8.1
Unicondylar and
fixed 1.4 1.8 2.1 2.3 2.0 2.1 2.2 2.6 2.6 2.9
mobile 6.5 6.7 6.5 6.8 6.7 6.8 6.6 6.2 5.8 5.2bearing type unknown
0.2 0.2 0.1 0.2 0.1 0.2 0.2 0.1 0.1 0.0
All patello-femoral 1.0 1.0 1.0 1.1 1.4 1.5 1.5 1.4 1.5 1.3
Knee type unknown 0.2 0.01
All types 13,512 27,697 41,846 49,459 66,587 73,806 75,494 78,061 81,032 81,534
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2,722 consultant surgeons carried out at least one type of primary knee arthroplasty between 2003 and 2012. The median number of primary operations performed by a surgeon was 107 (IQR 21 to 315) over the whole period. The total number of surgical units in which at least one primary knee operation was carried out in the time period was 448. The median number of operations performed in a unit was 954 (IQR 460 to 1825).
Table 3.16 summarises the key features of the distribution of primary operations carried out by surgeons and units in terms of the proportions who performed each type of procedure and the median and IQR of the number of procedures they carried out. Surgeons and units who performed fewer than 10
operations over the whole period were excluded (i.e. 475 surgeons and 15 units, respectively).
Surgeons performing cemented TKR carried out a median of 137 operations of this type over the whole period they were observed with an IQR of 47 to 316 procedures. This means that 25% of surgeons had a caseload of fewer than 47 cemented total knee replacements over the time and 25% of surgeons carried out more than 316 procedures. The 10% of surgeons with the highest caseload completed between 517 and 2,599 all cemented primary TKRs (not shown in table 3.16). The majority of surgeons and units carried out very few, if any, uncemented and hybrid TKRs.
Table 3.16 Distribution of consultant surgeon and unit caseload12 for each fixation type.
Distribution of primary knee operations by fixation type performed by
(i) Consultant Surgeons (n=2,247) (ii) Surgical Units (n=433)% performing
this fixation type Median IQR
% performing this fixation
type Median IQRTotal knee replacement
All cemented 99.7 137 (47-316) 100.0 838 (390-1591)
All uncemented 26.6 6 (1-41) 64.0 16 (2-77)
All hybrid 29.5 2 (1-5) 71.4 4 (2-14)
Unicompartmental knee replacement
All unicondylar 57.2 13 (3-43) 97.7 69 (25-148)
All patello-femoral 30.7 5 (2-13) 82.7 11 (4-27)
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12 Only surgeons or units with at least 10 primary operations recorded in the NJR are presented in the tables. The total count of surgeons who had performed any knee operation between 2003 and 2012 is 2,722. Of these, 475 have performed fewer than 10 operations over this period. Excluding these from reported results leaves 2,247 surgeons. The total count of units who had performed any knee operation between 2003 and 2012 is 448. Of these, 15 have performed fewer than 10 operations over this period. Excluding these from reported results leaves 433 units.
Table 3.17 shows the age distribution of patients undergoing a first replacement of their knee joint. The median age of a person receiving a cemented total knee replacement was 70 years (with an inter-quartile range of 64 to 77 years). However, for unicompartmental primary knee surgery, patients were typically 6 (unicondylar) and 11 years younger
(patello-femoral). The 99th percentile of patient age for all types of surgery ranged between 85 and 88 years, indicating that surgery was rarely undertaken in a person aged 90 or older, although the maximum age of a patient who underwent primary surgery over the nine year period was aged 102 years.
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Table 3.17 Age (in years) at primary operation13 for different types of knee replacement; by fixation and bearing type.
Fixation Bearing TypeMedian (IQR)14
of ages Minimum age15 Maximum ageTotal knee replacement
All cemented 70 (64-77) 14 102
Cemented and
unconstrained, fixed 70 (64-77) 16 101
unconstrained, mobile 69 (62-75) 23 97
posterior-stabilised, fixed 71 (64-77) 15 102
posterior-stabilised, mobile 65 (59-73) 22 95
constrained, condylar 72 (63-79) 20 96
all polyethylene tibia 75 (70-79) 25 96
bearing type unknown 70 (63-77) 14 99
All uncemented 69 (62-75) 20 101
All hybrid 69 (62-76) 23 96
Hybrid and
unconstrained, fixed 69 (62-76) 24 99
unconstrained, mobile 69 (62-76) 25 101
posterior-stabilised, fixed 66 (59-74) 20 93
other bearing type 65 (57-73) 33 95
bearing type unknown 69 (61-76) 23 91
Unicompartmental knee replacement
All unicondylar 64 (57-70) 18 100
Unicondylar and
fixed 63 (56-70) 18 100
mobile 64 (58-71) 23 100
bearing type unknown 63 (56-70) 31 90
All patello-femoral 59 (51-68) 1 93
Fixation unknown 69 (59-77) 43 85
All types 70 (63-76) 1 102
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13 Ages at primary operation excluding those 19 cases where age was recorded as zero years. Based on a total of 589,009 joints.14 The interquartile range (IQR) shows the age range of the middle 50% of patients arranged in order of their age at time of primary knee operation.15 The lowest age excluding 19 cases where age was recorded as zero years. The patello-femoral joint replacement in a one year old in the table above
certainly represents a data input error.
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3.3.2 Revisions after primary knee surgery
Table 3.18 shows Kaplan-Meier estimates of the cumulative percentage probability of first revision, for any cause, for all cases combined and then subdivided by knee types. Estimates are shown, together with 95% Confidence Intervals (95% CIs), at 30 and 90 days after the primary operation and at each anniversary up to the 9th.
These estimates are not adjusted for other factors such as age and gender and these will be looked at in the future. The unicondylar and patello-femoral replacements seem to have done particularly badly
but are generally used in younger patients. This may be a function of milder disease in these patients, or the desire to delay a total knee replacement for as long as possible. Younger patients too may be more active which puts more strain on their implants.
Figure 3.6 compares the cumulative hazard of a first revision for the main types of primary knee replacement surgery over time. Patello-femoral and unicompartmental knee replacements were revised much earlier than total knee replacements. All curves increase in a reasonably linear fashion as time increases, indicating that the hazard rate was, by and large, constant over time.
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Tab
le 3
.18
Kap
lan-
Mei
er e
stim
ates
of t
he c
umul
ativ
e pe
rcen
tage
pro
babi
lity
of fi
rst r
evis
ion
(95%
CI)
at s
peci
fied
times
afte
r pr
imar
y kn
ee
repl
acem
ent,
by fi
xatio
n an
d be
arin
g ty
pe.
Cum
ulat
ive
per
cent
age
pro
bab
ility
of
a fir
st r
evis
ion
(95%
CI)
at t
ime
sho
wn
if tim
e el
apse
d s
ince
pri
mar
y o
per
atio
n is
:
Fix
atio
n/b
eari
ng t
ype
30
day
s90
day
s1
year
2 ye
ars
3 ye
ars
4 ye
ars
5 ye
ars
6 ye
ars
7 ye
ars
8 ye
ars
9 ye
ars
Tota
l kne
e re
pla
cem
ent
All
cem
ente
d0.
03
(0.0
3-0.
04)
0.07
(0
.07-
0.08
)0.
38
(0.3
6-0.
40)
0.96
(0
.93-
0.99
)1.
45
(1.4
1-1.
49)
1.81
(1
.76-
1.85
)2.
11
(2.0
6-2.
16)
2.36
(2
.31-
2.42
)2.
63
(2.5
6-2.
70)
2.88
(2
.80-
2.97
)3.
12
(3.0
1-3.
24)
Cem
ente
d an
d
unco
nstr
aine
d, fi
xed
0.02
(0
.02-
0.03
)0.
06
(0.0
5-0.
07)
0.33
(0
.31-
0.35
)0.
88
(0.8
4-0.
92)
1.33
(1
.29-
1.38
)1.
66
(1.6
1-1.
71)
1.92
(1
.86-
1.99
)2.
19
(2.1
2-2.
26)
2.44
(2
.36-
2.53
)2.
71
(2.6
0-2.
81)
2.90
(2
.77-
3.04
)un
cons
trai
ned,
m
obile
0.09
(0
.06-
0.13
)0.
13
(0.0
9-0.
18)
0.51
(0
.43-
0.60
)1.
22
(1.0
9-1.
37)
1.84
(1
.67-
2.03
)2.
35
(2.1
5-2.
57)
2.65
(2
.43-
2.89
)2.
89(2
.65-
3.16
)3.
14
(2.8
6-3.
44)
3.31
(2
.99-
3.66
)3.
78
(3.2
4-4.
40)
post
erio
r-st
abilis
ed,
fixed
0.04
(0
.03-
0.05
)0.
08
(0.0
7-0.
10)
0.43
(0
.39-
0.47
)1.
03
(0.9
7-1.
09)
1.53
(1
.45-
1.61
)1.
89
(1.8
0-1.
99)
2.28
(2
.18-
2.40
)2.
52
(2.4
0-2.
64)
2.79
(2
.65-
2.94
)3.
06
(2.8
9-3.
24)
3.32
(3
.08-
3.58
)po
ster
ior-
stab
ilised
, m
obile
0.07
(0
.03-
0.16
)0.
13
(0.0
7-0.
24)
0.68
(0
.52-
0.89
)1.
56
(1.2
9-1.
87)
2.22
(1
.89-
2.60
)2.
73
(2.3
5-3.
17)
3.08
(2
.66-
3.56
)3.
53
(3.0
4-4.
09)
3.84
(3
.28-
4.49
)3.
84
(3.2
8-4.
49)
5.01
(3
.55-
7.06
)
cons
trai
ned
cond
ylar
0.14
(0
.04-
0.43
)0.
47
(0.2
5-0.
87)
1.02
(0
.66-
1.58
)1.
85
(1.3
0-2.
61)
2.56
(1
.87-
3.51
)3.
04
(2.2
4-4.
13)
3.35
(2
.47-
4.54
)3.
35
(2.4
7-4.
54)
3.65
(2
.64-
5.04
)4.
48
(2.8
7-6.
96)
4.48
(2
.87-
6.96
)
all p
olye
thyl
ene
tibia
00.
10
(0.0
5-0.
23)
0.39
(0
.25-
0.61
)0.
93
(0.6
8-1.
27)
1.48
(1
.12-
1.95
)1.
74
(1.3
3-2.
27)
2.29
(1
.76-
2.98
)2.
41
(1.8
4-3.
15)
2.64
(1
.96-
3.55
)2.
64
(1.9
6-3.
55)
2.64
(1
.96-
3.55
)be
arin
g ty
pe
unkn
own
0.01
(0
.05-
0.20
)0.
19
(0.1
1-0.
32)
0.63
(0
.47-
0.85
)1.
56
(1.2
9-1.
89)
2.27
(1
.92-
2.68
)2.
80
(2.4
0-3.
27)
3.27
(2.8
1-3.
80)
3.40
(2
.92-
3.96
)3.
80
(3.2
3-4.
47)
3.92
(3
.31-
4.64
)4.
36
(3.3
4-5.
60)
All
unce
men
ted
0.04
(0
.02-
0.07
)0.
12
(0.0
8-0.
16)
0.61
(0
.53-
0.70
)1.
50
(1.3
6-1.
65)
2.11
(1.9
4-2.
29)
2.50
(2.3
1-2.
70)
2.86
(2
.64-
3.08
)3.
16
(2.9
2-3.
41)
3.47
(3
.20-
3.77
)3.
69
(3.3
7-4.
02)
4.03
(3.6
1-4.
50)
All
hyb
rid
0.03
(0
.01-
0.11
)0.
07
(0.0
3-0.
17)
0.54
(0
.39-
0.74
)1.
31
(1.0
6-1.
61)
1.75
(1
.46-
2.10
)2.
00
(1.6
9-2.
38)
2.32
(1
.96-
2.73
)2.
55
(2.1
6-3.
00)
2.93
(2
.48-
3.46
)3.
11
(2.6
2-3.
68)
3.44
(2
.70-
4.39
)
Unc
emen
ted/
hybr
id a
nd
unco
nstr
aine
d, fi
xed
0.02
(0
.01-
0.05
)0.
07
(0.0
4-0.
13)
0.59
(0
.49-
0.71
)1.
47
(1.3
0-1.
66)
1.96
(1
.75-
2.18
)2.
22
(2.0
0-2.
46)
2.51
(2.2
7-2.
77)
2.66
(2
.40-
2.95
)3.
02
(2.7
1-3.
36)
3.12
(2
.79-
3.48
)3.
60
(3.0
4-4.
27)
unco
nstr
aine
d,
mob
ile0.
05
(0.0
3-0.
11)
0.15
(0
.10-
0.22
)0.
63
(0.5
1-0.
76)
1.38
(1
.21-
1.59
)2.
01
(1.7
9-2.
26)
2.42
(2
.17-
2.71
)2.
79
(2.5
0-3.
11)
3.13
(2
.80-
3.49
)3.
38
(3.0
2-3.
79)
3.50
(3
.10-
3.94
)3.
75
(3.2
4-4.
32)
post
erio
r st
abilis
ed,
fixed
0.04
(0
.01-
0.29
)0.
08
(0.0
2-0.
32)
0.42
(0
.23-
0.78
)1.
80
(1.3
2-2.
44)
2.63
(2
.03-
3.40
)3.
31
(2.6
1-4.
19)
4.11
(3
.28-
5.15
)4.
65
(3.7
2-5.
80)
5.25
(4
.18-
6.57
)6.
70
(5.1
5-8.
70)
6.70
(5
.15-
8.70
)
othe
r co
nstr
aint
0
00.
31
(0.0
4-2.
18)
2.23
(1
.07-
4.62
)2.
88
(1.5
1-5.
47)
3.22
(1
.74-
5.90
)3.
22
(1.7
4-5.
90)
4.28
(2
.42-
7.53
)4.
28
(2.4
2-7.
53)
4.28
(2
.42-
7.53
)4.
28
(2.4
2-7.
53)
bear
ing
type
un
know
n0.
20
(0.0
3-1.
43)
0.20
(0
.03-
1.43
)0.
82
(0.3
1-2.
17)
1.24
(0
.56-
2.74
)2.
41
(1.3
4-4.
32)
2.91
(1
.70-
4.97
)3.
20
(1.9
0-5.
36)
3.95
(2
.41-
6.45
)4.
47
(2.7
4-7.
28)
4.47
(2
.74-
7.28
)4.
47
(2.7
4-7.
28)
© National Joint Registry 2013
Con
tinue
d >
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
167www.njrcentre.org.uk
Cum
ulat
ive
per
cent
age
pro
bab
ility
of
a fir
st r
evis
ion
(95%
CI)
at t
ime
sho
wn
if tim
e el
apse
d s
ince
pri
mar
y o
per
atio
n is
:
Fix
atio
n/b
eari
ng t
ype
30
day
s90
day
s1
year
2 ye
ars
3 ye
ars
4 ye
ars
5 ye
ars
6 ye
ars
7 ye
ars
8 ye
ars
9 ye
ars
Uni
com
par
tmen
tal k
nee
rep
lace
men
t
All
unic
ond
ylar
0.05
(0
.03-
0.07
)0.
15
(0.1
2-0.
19)
1.22
(1
.13-
1.32
)3.
12
(2.9
6-3.
29)
4.59
(4
.39-
4.80
)5.
87(5
.64-
6.12
)7.
06
(6.7
8-7.
34)
8.22
(7
.89-
8.56
)9.
40(9
.00-
9.81
)10
.63
(10.
13-1
1.15
)11
.57
(10.
92-1
2.26
)
Uni
cond
ylar
and
fixed
0.05
(0
.02-
0.11
)0.
10
(0.0
6-0.
17)
0.89
(0
.74-
1.07
)3.
01
(2.7
0-3.
34)
4.70
(4
.29-
5.14
)6.
22
(5.7
3-6.
76)
7.41
(6
.83-
8.02
)8.
37
(7.7
1-9.
07)
9.28
(8
.52-
10.1
1)9.
74
(8.8
9-10
.67)
10.7
2 (9
.34-
12.2
9)
mob
ile
0.05
(0
.03-
0.08
)0.
17
(0.1
3-0.
22)
1.35
(1
.23-
1.47
)3.
20
(3.0
1-3.
40)
4.59
(4
.36-
4.84
)5.
82
(5.5
5-6.
11)
7.02
(6
.70-
7.35
)8.
24
(7.8
6-8.
64)
9.50
(9
.04-
9.99
)10
.94
(10.
35-1
1.56
)11
.86
(11.
11-1
2.65
)be
arin
g ty
pe
unkn
own
00.
14
(0.0
2-0.
97)
0.84
(0
.38-
1.86
)1.
43
(0.7
7-2.
65)
3.17
(2
.05-
4.89
)3.
81
(2.5
3-5.
71)
4.14
(2
.76-
6.18
)5.
41
(3.6
1-8.
09)
6.07
(4
.00-
9.17
)7.
22
(4.5
2-11
.42)
9.11
(5
.27-
15.5
0)
All
pat
ello
-fem
ora
l0
0.05
(0
.02-
0.14
)1.
09
(0.8
7-1.
36)
3.22
(2
.81-
3.68
)5.
50
(4.9
4-6.
12)
7.43
(6
.74-
8.19
)9.
69
(8.8
3-10
.62)
10.8
1 (9
.85-
11.8
6)12
.88
(11.
65-1
4.23
)14
.75
(13.
15-1
6.52
)16
.11
(14.
09-1
8.39
)
Oth
ers/
unkn
ow
n0
00
00
00
02.
63
(0.3
7-17
.25)
2.63
(0
.37-
17.2
5)0
All
typ
es0.
03
(0.0
3-0.
04)
0.08
(0
.07-
0.09
)0.
48
(0.4
6-0.
49)
1.22
(1
.19-
1.25
)1.
83
(1.7
9-1.
87)
2.29
(2.2
4-2.
34)
2.70
(2
.65-
2.76
)3.
05
(2.9
9-3.
12)
3.43
(3
.36-
3.50
)3.
79
(3.7
0-3.
88)
4.12
(4
.00-
4.24
)
© National Joint Registry 2013
Tab
le 3
.18
(con
tinue
d)
168 www.njrcentre.org.uk
Figure 3.6 Cumulative hazard (x100) of a first revision for different types of primary knee replacement at increasing years after the primary surgery (with 95% CI).
22
20
18
16
14
12
10
8
6
4
2
0 1 2 3 4 5 6 7 8 9
Years since primary surgery
Cum
ulat
ive
haza
rd x
100
Cemented
Uncemented
Hybrid
490,939
31,382
7,307
7,881
51,474
413,315
28,199
6,845
6,679
44,107
337,600
24,441
6,295
5,361
36,376
267,439
20,415
5,471
4,181
28,915
202,689
15,975
4,508
3,071
21,999
142,760
11,425
3,504
2,028
15,428
91,079
7,320
2,595
1,202
9,918
54,676
4,369
1,778
712
5,825
25,627
2,142
896
335
2,762
7,913
670
280
105
828
Patello-femoral
Unicondylar
Numbers at risk
© N
atio
nal J
oint
Reg
istr
y 20
13
Figure 3.7 compares the cumulative hazard of a first revision of a prosthesis for different bearing types of cemented TKR. There is no marked separation of the cumulative hazard curves for any of the types of bearing shown and the confidence intervals for each type overlap. This strongly suggests that the different bearing types by and large have similar cumulative
hazard of the need of revision surgery. However, the curvature of the hazard curves of each type over time indicates that the hazard rate changes over time with the risk of needing a revision of the implant in earlier years (up to five years after surgery) being higher than later times after surgery.
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
169www.njrcentre.org.uk
Figure 3.7 Comparison of the cumulative hazard (x100) of a knee prosthesis first revision for different bearing types at increasing years after the primary surgery when the primary arthroplasty method of fixation was cemented only (with 95% CI).
8
7
6
5
4
3
2
1
0 1 2 3 4 5 6 7 8 9
Years since primary surger
Cum
ulat
ive
haza
rd x
100
y
PS mobile
C cond
PT
8,276
2,173
6,124
25,931
123,162
317,914
7,359
7,257
1,661
4,356
23,743
104,490
265,085
6,723
6,147
1,294
2,973
21,054
85,328
215,218
5,586
4,958
956
2,147
17,676
67,223
169,856
4,623
3,854
730
1,588
14,007
50,491
128,326
3,693
2,812
537
976
9,881
35,159
90,705
2,690
1,782
335
465
5,945
22,327
58,653
1,572
942
214
211
3,151
13,414
35,853
891
352
106
84
1,279
6,469
16,905
432
104
25
30
378
1,986
5,226
164
UC mobile
PS �xed
UC �xed
Unknown
Numbers at risk
© N
atio
nal J
oint
Reg
istr
y 20
13Key: UC fixed=unconstrained and fixed, UC mobile= unconstrained and mobile, PS fixed=posterior-stabilised and fixed, PS mobile=posterior-stabilised and mobile, C cond=constrained and condylar, PT=polyethylene tibia.
3.3.3 Revisions for different causes after primary knee surgery
Methodological note
The previous section looked at revisions for any reason. For any revision, a number of reasons may be related to the first revision of the implant. The reasons are not mutually exclusive of each other. Incidence rates for each reason have been calculated
using patient–time incidence rates; the total number of revisions for that reason divided by the total number of individual patient-years at risk. The figures are given as the numbers of revisions for that reason per 1,000 years at risk. This method is appropriate if the hazard rate remains constant.
Table 3.19 shows the revision rates for each reason recorded on the clinical assessment forms for joint replacement/revision surgery for all cases and then
subdivided by fixation type and whether the primary procedure was a TKR or an UKR. Table 3.20 shows these first knee revision rates for each reason
170 www.njrcentre.org.uk
by fixation/bearing type. In earlier versions of the clinical assessment forms recording the type of joint replacement or revision operation to be undertaken and reasons for this, both ‘stiffness’ and ‘arthritis’ were not originally included as options for indicating the need for revising the implant. Therefore, for these reasons for revision, there are fewer years at which patients are at risk specifically for these categories.
The main reasons for revision were pain, aseptic loosening and infection in a primary TKR. Pain and aseptic loosening were also primary reasons given for revision of an UKR (and amongst the highest incidence rates for revision) alongside implant instability and failure and dislocation. Progression of arthritis was a key reason for revision of both unicondylar and patello-femoral UKRs.
Table 3.19 Revision rates (95% CI), expressed as number of revisions per 1,000 patient-years, for each recorded reason for first knee revision. Rates shown are for all revised cases and by fixation type.
Patient-years
at risk (x1,000)
Number of revisions per 1,000 patient-years for:
PainDislocation/ subluxation Infection
Aseptic loosening Lysis
Periprosthetic fracture
Implant fracture
All cases* 2173.51.18
(1.14-1.23)0.23
(0.21-0.25)1.10
(1.06-1.15)1.41
(1.36-1.46)0.25
(0.23-0.28)0.14
(0.12-0.15)0.02
(0.02-0.03)By fixation:
Cemented 1,800.00.78
(0.74-0.82)0.14
(0.12-0.16)1.16
(1.11-1.21)1.05
(1.01-1.10)0.23
(0.21-0.26)0.11
(0.10-0.13)0.02
(0.01-0.02)
Uncemented 130.81.30
(1.12-1.51)0.30
(0.22-0.41)0.90
(0.75-1.08)2.01
(1.78-2.27)0.28
(0.20-0.38)0.15
(0.10-0.24)0.07
(0.04-0.13)
Hybrid 35.90.95
(0.68-1.33)0.20
(0.09-0.41)1.23
(0.91-1.65)1.23
(0.91-1.65)0.25
(0.13-0.48)0.08
(0.03-0.26)0.06
(0.01-0.22)
Unicondylar 191.8 4.16
(3.88-4.46)0.93
(0.81-1.08)0.76
(0.64-0.89)4.29
(4.01-4.59)0.48
(0.39-0.59)0.33
(0.26-0.43)0.05
(0.02-0.09)
Patello-femoral 27.6 6.37
(5.50-7.38)1.01
(0.70-1.47)0.36
(0.19-0.67)2.24
(1.75-2.88)0.07
(0.02-0.29)0.25
(0.12-0.53)0.11
(0.04-0.34)
Patient-years
at risk (x1,000)
Number of revisions per 1,000 patient-years for: Patient-years
at risk (x1,000) Stiffness**
Patient-years
at risk (x1,000)
Arthritis***
Implant failure
Component size
mismatch MalalignmentOther
indication
All cases* 2173.50.27
(0.25-0.29)0.73
(0.70-0.77)0.44
(0.41-0.47)0.64
(0.61-0.68)2000.0
0.39 (0.36-0.42)
893.10.42
(0.38-0.46)By fixation:
Cemented 1,800.00.17
(0.15-0.19)0.67
(0.63-0.70)0.37
(0.34-0.40)0.42
(0.39-0.45)1700.0
0.39 (0.36-0.42)
744.10.16
(0.14-0.20)
Uncemented 130.80.23
(0.16-0.33)0.93
(0.78-1.11)0.58
(0.46-0.73)0.50
(0.39-0.63)119.2
0.53 (0.41-0.68)
46.30.22
(0.12-0.40)
Hybrid 35.90.33
(0.19-0.59)0.84
(0.58-1.20)0.39
(0.23-0.66)0.25
(0.13-0.48)30.9
0.36 (0.20-0.64)
9.7 0
Unicondylar 191.81.06
(0.92-1.21)1.14
(1.00-1.30)0.80
(0.69-0.94)2.37
(2.16-2.60)178.1
0.29 (0.22-0.38)
12.72.27
(1.96-2.63)Patello-femoral
27.61.73
(1.31-2.31)1.09
(0.76-1.55)1.85
(1.40-2.43)4.05
(3.37-4.88)25.9
0.66 (0.41-1.06)
80.24.81
(3.74-6.18)
Table 3.19 (continued)
*Including the one case with bearing type unknown. **This reason was not asked in the earliest version of the clinical assessment form MDSv1 for joint replacement or revision surgery. Therefore, there are fewer patient-years at risk. ***This reason was not asked in the early versions of the clinical assessment forms MDSv1 and MDSv2 for joint replacement/revision surgery and hence, for these reasons, there are fewer patient-years at risk.
© N
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
171www.njrcentre.org.uk
Table 3.20 Revision rates (95% CI), expressed as number of revisions per 1,000 patient-years, for each recorded reason for first knee revision. Rates shown are for each fixation/bearing surface sub-group.
By fixation/bearing
Patient-years
at risk (x1,000)
Number of revisions per 1,000 patient-years for:
PainDislocation/ subluxation Infection
Aseptic loosening Lysis
Periprosthetic fracture
Implant fracture
Total knee replacement
Cementedunconstrained, fixed
1,100.00.76
(0.71-0.81)0.13
(0.11-0.15)1.05
(0.99-1.11)0.93
(0.87-0.99)0.21
(0.18-0.24)0.08
(0.07-0.10)0.02
(0.01-0.03)unconstrained, mobile
110.21.09
(0.91-1.30)0.24
(0.16-0.35)1.23
(1.04-1.46)1.35
(0.58-1.43)0.35
(0.26-0.48)0.15
(0.10-0.25)0.01
(0.00-0.06)posterior-stabilised, fixed
448.50.68
(0.61-0.76)0.13
(0.10-0.17)1.38
(1.27-1.49)1.24
(1.14-1.34)0.26
(0.21-0.31)0.16
(0.13-0.20)0.01
(0.00-0.02)posterior-stabilised, mobile
32.31.30
(0.96-1.76)0.28
(0.14-0.54)1.14
(0.83-1.58)1.18
(0.86-1.62)0.31
(0.17-0.57)0.28
(0.14-0.54)0.09
(0.03-0.29)constrained, condylar
6.90.58
(0.22-1.54)0.58
(0.22-1.50)3.61
(2.44-5.35)1.45
(0.78-2.69)0.43
(0.14-1.34)0.43
(0.14-1.34)0
all polyethylene tibia
15.80.63
(0.34-1.18)0.32
(0.13-0.76)1.39
(0.92-2.11)0.89
(0.52-1.49)0.25
(0.09-0.67)0.13
(0.03-0.51)0
Bearing type unknown
30.11.30
(0.95-1.77)0.17
(0.07-0.40)1.46
(1.09-1.97)1.70
(1.29-2.23)0.23
(0.11-0.49)0.13
(0.05-0.35)0.07
(0.02-0.27)
Uncemented/Hybridunconstrained, fixed
83.90.98
(0.79-1.21)0.17
(0.10-0.40)1.00
(0.81-1.24)1.79
(1.52-2.10)0.20
(0.13-0.33)0.10
(0.05-0.19)0.05
(0.02-0.13)unconstrained, mobile
67.01.37
(1.12-1.68)0.37
(0.25-0.55)0.92
(0.72-1.19)1.85
(1.55-2.21)0.33
(0.22-0.50)0.19
(0.11-0.33)0.09
(0.04-0.20)posterior-stabilised, fixed
11.31.96
(1.29-2.97)0.62
(0.30-1.30)1.16
(0.67-1.99)2.13
(1.43-3.18)0.36
(0.13-0.95)0.18
(0.04-0.71)0
other constraint 1.83.26
(1.46-7.25)0
0.54 (0.08-3.85)
0 0 0 0
Bearing type unknown
2.70.74
(0.19-2.96)0
0.74 (0.19-2.96)
3.33 (1.73-6.40)
0.74 (0.19-2.96)
00.37
(0.05-2.6)
Unicompartmental knee replacement
Unicondylar
fixed 46.44.96
(4.35-5.64)0.13
(0.06-0.29)0.90
(0.67-1.22)4.70
(4.11-5.36)0.43
(0.28-0.67)0.32
(0.19-0.54)0.06
(0.02-0.20)
mobile 142.23.91
(3.60-4.25)1.21
(1.04-1.40)0.71
(0.58-0.86)4.20
(3.88-4.56)0.51
(0.40-0.64)0.34
(0.26-0.46)0.04
(0.01-0.08)Bearing type unknown
3.23.77
(2.14-6.63)0.31
(0.04-2.23)0.63
(0.16-2.51)2.20
(1.05-4.61)0 0
0.31 (0.04-2.20)
Patello-femoral
27.66.37
(5.50-7.38)1.00
(0.70-1.50)0.36
(0.19-0.67)2.24
(1.75-2.88)0.07
(0.02-0.29)0.25
(0.12-0.53)0.11
(0.04-0.34)Others/unknown
0.3 0 0 02.92
(0.41-20.76)0 0 0
© N
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Reg
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Blue italic estimates based on a small group size (n<30), therefore estimates are unreliable. *This reason was not asked in the earliest version of the clinical assessment form MDSv1 for joint replacement or revision surgery. Therefore, there are fewer patient-years at risk. **This reason was not asked in the early versions of the clinical assessment forms MDSv1 and MDSv2 for joint replacement/revision surgery and hence, for these reasons, there are fewer patient-years at risk.
Continued >
172 www.njrcentre.org.uk
Table 3.20 (continued)
By fixation/bearing
Patient-years
at risk (x1,000)
Number of revisions per 1,000 patient-years for: Patient-
years at risk
(x1,000) Stiffness*
Patient-years
at risk (x1,000) Arthritis**
Implant failure
Component size
mismatch MalalignmentOther
indicationCementedunconstrained, fixed
1,100.00.14
(0.12-0.16)0.62
(0.58-0.67)0.38
(0.34-0.42)0.42
(0.38-0.46)1,100.0
0.38 (0.35-0.42)
477.2 0.14
(0.12-0.19)unconstrained, mobile
110.20.28
(0.20-0.40)1.06
(0.89-1.27)0.48
(0.37-0.63)0.44
(0.34-0.59)103.9
0.56 (0.43-0.72)
40.80.10
(0.04-0.26)posterior-stabilised, fixed
448.50.19
(0.16-0.24)0.64
(0.57-0.72)0.34
(0.29-0.39)0.35
(0.30-0.41)414.0
0.31 (0.26-0.37)
191.00.21
(0.15-0.29)posterior-stabilised, mobile
32.30.28
(0.14-0.54)1.21
(0.88-1.65)0.25
(0.12-0.49)1.08
(0.78-1.51)30.9
0.97 (0.68-1.39)
12.40.16
(0.04-0.64)
constrained, condylar
6.90.43
(0.14-1.34)1.01
(0.48-2.12)0.14
(0.02-1.03)0.29
(0.07-1.16)6.4
0.31 (0.08-1.25)
2.7 0
all polyethylene tibia
15.80.25
(0.09-0.67)0.57
(0.30-1.09)0.25
(0.09-0.67)0.70
(0.39-1.26)15.4
0.39 (0.17-0.87)
9.50.21
(0.05-0.84)bearing type unknown
30.10.27
(0.13-0.53)0.70
(0.45-1.07)0.37
(0.20-0.66)0.76
(0.51-1.15)27.5
0.33 (0.17-0.63)
10.60.38
(0.14-1.00)
Uncemented/Hybridunconstrained, fixed
83.90.24
(0.15-0.37)0.85
(0.67-1.07)0.44
(0.32-0.61)0.41
(0.29-0.57)75.2
0.44 (0.31-0.62)
29.60.07
(0.02-0.27)unconstrained, mobile
67.00.27
(0.17-0.43)0.85
(0.66-1.10)0.58
(0.43-0.79)0.34
(0.23-0.52)60.9
0.43 (0.29-0.63)
22.20.36
(0.18-0.72)posterior-stabilised, fixed
11.30.18
(0.04-0.71)1.33
(0.80-2.21)1.16
(0.67-1.99)1.16
(0.67-1.99)10.1
0.99 (0.53-1.84)
3.4 0
other constraint 3.30.54
(0.08-3.85)2.17
(0.81-5.78)0
0.54 (0.08-3.85)
1.81.10
(0.28-4.40)0.3 0
Bearing type unknown
2.70.37
(0.05-2.63)1.85
(0.77-4.45)0.37
(0.05-2.63)1.11
(0.36-3.44)2.1
1.40 (0.45-4.33)
0.5 0
Unicompartmental knee replacement
Unicondylar
fixed 46.40.82
(0.60-1.13)0.93
(0.69-1.25)0.80
(0.58-1.10)1.94
(1.58-2.38)43.9
0.41 (0.26-0.65)
21.12.84
(2.21-3.66)
mobile 142.21.14
(0.98-1.33)1.20
(1.03-1.40)0.82
(0.68-0.98)2.53
(2.28-2.81)131.3
0.25 (0.18-0.35)
57.82.08
(1.74-2.48)Bearing type unknown
3.20.94
(0.30-2.92)1.26
(0.47-3.35)0.31
(0.04-2.23)1.26
(1.05-4.61)3.0 0 1.3
1.56 (0.39-6.22)
Patello-femoral
27.61.74
(1.31-2.31)1.09
(0.76-1.55)1.85
(1.40-2.43)4.05
(3.37-4.88)25.9
0.66 (0.41-1.06)
12.74.81
(3.74-6.18)Other/unknown
0.32.92
(0.41-21.00)0 0 0 0.3 0 -
Blue italic estimates based on a small group size (n<30), therefore estimates are unreliable. *This reason was not asked in the earliest version of the clinical assessment form MDSv1 for joint replacement or revision surgery. Therefore, there are fewer patient-years at risk. **This reason was not asked in the early versions of the clinical assessment forms MDSv1 and MDSv2 for joint replacement/revision surgery and hence, for these reasons, there are fewer patient-years at risk.
© N
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
173www.njrcentre.org.uk
3.3.4 Revisions after primary knee surgery by main brands for TKR and UKR
Tables 3.21 and 3.22 show the Kaplan-Meier estimates of the cumulative percentage probability of first revision (for any reason) of a primary TKR (table 3.21) and primary UKR (table 3.22) by implant brand. We have only included those brands that have been used in a primary knee procedure in 1,000 or more operations. Figures in blue indicate those time points
where fewer than 100 primary knee joint replacements remain at risk. No attempt has been made to adjust for other factors that may influence the chance of revision so the figures are unadjusted probabilities.
Table 3.23 shows Kaplan-Meier estimates of the cumulative percentage probability of first revision of a primary TKR or primary UKR by implant brand and bearing type for those brands/bearing types which were implanted on at least 1,000 occasions.
174 www.njrcentre.org.uk
Table 3.21 Kaplan-Meier estimated cumulative percentage probability of first revision (95% CI) of a primary total knee replacement by main type of implant brand at the indicated number of years after primary operation.16
Brand17
Number of knee
joints
Cumulative percentage probability of a first revision (95% CI) at time shown if time elapsed since primary operation is
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 yearsAdvance MP
5,2580.29
(0.17-0.49)1.20
(0.91-1.58)1.62
(1.27-2.06)1.98
(1.58-2.48)2.22
(1.78-2.77)2.94
(2.33-3.71)3.17
(2.50-4.01)3.42
(2.63-4.45)3.98
(2.79-5.66)
AGC 53,4400.28
(0.24-0.33)0.92
(0.83-1.01)1.38
(1.28-1.50)1.74
(1.62-1.88)1.97
(1.83-2.11)2.30
(2.14-2.47)2.54
(2.35-2.74)2.85
(2.62-3.11)3.12
(2.83-3.45)
Columbus 4,3190.45
(0.28-0.72)1.54
(1.16-2.04)2.07
(1.60-2.66)2.52
(1.97-3.23)2.88
(2.23-3.73)3.29
(2.48-4.37)4.37
(2.58-7.35)4.37
(2.58-7.35)-
E-Motion Bicondylar Knee
2,0010.69
(0.40-1.19)1.55
(1.05-2.27)2.54
(1.84-3.50)2.64
(1.92-3.62)2.79
(2.03-3.83)3.55
(2.41-5.22)3.55
(2.41-5.22)3.55
(2.41-5.22)3.55
(2.41-5.22)
Endoplus Bicondylar Knee
13,8330.70
(0.57-0.86)1.34
(1.16-1.55)1.81
(1.59-2.05)2.18
(1.94-2.45)2.44
(2.17-2.74)2.68
(2.38-3.02)2.85
(2.53-3.23)3.00
(2.58-3.48)3.00
(2.58-3.48)
Genesis 2 30,0100.42
(0.35-0.51)0.96
(0.84-1.10)1.39
(1.23-1.56)1.84
(1.64-2.06)2.07
(1.85-2.32)2.27
(2.01-2.56)2.34
(2.07-2.66)2.43
(2.11-2.79)2.43
(2.11-2.79)
Genesis 2 Oxinium
4,8320.55
(0.37-0.82)1.35
(1.03-1.77)2.25
(1.80-2.82)2.69
(2.17-3.34)3.37
(2.71-4.19)3.75
(2.99-4.71)4.50
(3.51-5.77)4.82
(3.69-6.29)4.82
(3.69-6.29)Insall-Burstein 2
2,0580.30
(0.13-0.66)0.90
(0.57-1.43)1.58
(1.11-2.24)2.17
(1.61-2.93)2.69
(2.04-3.53)3.08
(2.36-4.00)3.45
(2.67-4.46)3.79
(2.91-4.93)3.79
(2.91-4.93)
Kinemax 10,8620.24
(0.16-0.35)1.03
(0.86-1.25)1.76
(1.52-2.03)2.21
(1.95-2.51)2.67
(2.37-3.00)3.00
(2.68-3.36)3.49
(3.13-3.89)3.91
(3.50-4.37)4.30
(3.81-4.86)
LCS 2,0380.64
(0.37-1.10)1.09
(0.72-1.65)1.75
(1.26-2.43)2.06
(1.52-2.79)2.33
(1.75-3.10)2.39
(1.80-3.16)2.61
(1.99-3.43)2.74
(2.10-3.58)2.94
(2.25-3.83)LCS Complete
18,2350.47
(0.38-0.56)1.13
(0.98-1.31)1.70
(1.50-1.93)2.25
(2.01-2.53)2.64
(2.35-2.96)2.88
(2.56-3.24)3.12
(2.73-3.56)3.12
(2.73-3.56)-
Maxim 2,1240.30
(0.13-0.66)0.93
(0.59-1.47)1.63
(1.14-2.32)2.02
(1.46-2.80)2.33
(1.71-3.18)2.33
(1.71-3.18)3.02
(2.18-4.19)3.33
(2.35-4.72)5.05
(3.00-8.46)
MRK 5,5340.27
(0.16-0.45)0.76
(0.55-1.06)1.32
(1.01-1.71)1.63
(1.28-2.08)1.73
(1.36-2.21)1.83
(1.42-2.36)1.83
(1.42-2.36)3.33
(1.74-6.31)3.33
(1.74-6.31)Natural Knee II
2,5380.33
(0.17-0.67)0.88
(0.57-1.37)1.32
(0.91-1.91)1.76
(1.26-2.45)2.21
(1.62-3.01)2.66
(1.96-3.61)2.80
(2.06-3.79)2.80
(2.06-3.79)2.80
(2.06-3.79)
Nexgen 73,9660.37
(0.33-0.42)0.88
(0.81-0.96)1.38
(1.28-1.48)1.74
(1.63-1.87)2.16
(2.03-2.31)2.47
(2.31-2.64)2.75
(2.56-2.95)3.06
(2.82-3.32)3.26
(2.96-3.60)
Opetrak 2,2320.73
(0.44-1.20)2.14
(1.57-2.91)2.56
(1.92-3.41)3.26
(2.49-4.27)3.74
(2.87-4.87)4.09
(3.12-5.35)4.62
(3.33-6.39)5.43
(3.63-8.10)5.43
(3.63-8.10)PFC Sigma Bicondylar Knee
187,7280.36
(0.34-0.39)0.87
(0.82-0.91)1.28
(1.22-1.34)1.55
(1.49-1.62)1.81
(1.73-1.89)1.96
(1.88-2.05)2.14
(2.04-2.24)2.30
(2.19-2.42)2.45
(2.30-2.61)
Profix 3,9410.36
(0.22-0.61)0.98
(0.71-1.36)1.22
(0.91-1.63)1.52
(1.17-1.98)1.81
(1.41-2.33)2.28
(1.78-2.91)2.36
(1.84-3.01)2.36
(1.84-3.01)2.94
(1.90-4.53)
Rotaglide 1,0670.21
(0.05-0.84)0.58
(0.24-1.40)1.62
(0.92-2.85)2.01
(1.18-3.41)2.59
(1.55-4.30)3.08
(1.81-5.21)3.80
(2.15-6.66)3.80
(2.15-6.66)3.80
(2.15-6.66)
Rotaglide + 2,1080.57
(0.33-1.01)1.85
(1.35-2.53)2.79
(2.15-3.61)3.40
(2.69-4.31)3.66
(2.91-4.60)4.12
(3.30-5.14)4.62
(3.71-5.74)4.74
(3.81-5.90)5.45
(4.19-7.07)
Scorpio 34,1850.40
(0.34-0.47)1.17
(1.06-1.30)1.71
(1.57-1.86)2.08
(1.92-2.26)2.43
(2.25-2.63)2.70
(2.49-2.92)3.13
(2.87-3.40)3.26
(2.98-3.56)3.53
(3.13-3.97)
Triathlon 29,7660.44
(0.36-0.53)1.07
(0.94-1.22)1.54
(1.36-1.74)1.84
(1.62-2.10)1.93
(1.69-2.21)2.11
(1.78-2.50)2.98
(1.89-4.69)2.98
(1.89-4.69)-
Vanguard 17,0980.35
(0.26-0.46)0.95
(0.77-1.16)1.57
(1.30-1.89)2.04
(1.68-2.48)2.36
(1.92-2.91)2.56
(2.00-3.26)3.41
(2.02-5.70)3.41
(2.02-5.70)-
16 Estimates in blue indicate that fewer than 100 cases remain at risk at the time shown. 17 Brands shown have been used in at least 1,000 primary total knee replacement operations.
© N
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
175www.njrcentre.org.uk
Table 3.22 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) of a primary unicompartmental knee replacement by main type of implant brand at the indicated number of years after primary operation.18
Brand19
Number of knee
joints
Cumulative percentage probability of a first revision (95% CI) at time shown if time elapsed since primary operation is
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 years
Patello-femoral
Avon 3,7940.76
(0.52-1.11)2.35
(1.89-2.93)4.01
(3.37-4.76)5.58
(4.79-6.50)7.68
(6.69-8.82)8.51
(7.42-9.75)10.94
(9.49-12.60)12.53
(10.72-14.61)13.88
(11.61-16.56)
FPV 1,2270.89
(0.48-1.65)4.16
(3.06-5.64)6.35
(4.88-8.23)8.74
(6.80-11.21)9.16
(7.09-11.78)9.16
(7.09-11.78)9.16
(7.09-11.78)- -
Journey PFJ Oxinium
1,0641.98
(1.26-3.08)4.60
(3.39-6.23)8.20
(6.43-10.43)9.69
(7.68-12.19)13.89
(11.08-17.34)17.52
(12.98-23.41)17.52
(12.98-23.41)- -
Unicondylar
AMC/Uniglide 2,2792.58
(1.99-3.35)5.18
(4.28-6.26)6.98
(5.89-8.26)8.36
(7.12-9.81)9.07
(7.73-10.63)10.57
(8.94-12.48)11.78
(9.75-14.19)11.78
(9.75-14.19)11.78
(9.75-14.19)
MG Unicondylar 2,3610.89
(0.58-1.37)2.53
(1.97-3.25)3.83
(3.12-4.70)4.72
(3.92-5.69)5.71
(4.80-6.79)6.64
(5.62-7.84)7.03
(5.93-8.32)7.23
(6.08-8.59)7.23
(6.08-8.59)Oxford Partial Knee
35,9471.18
(1.07-1.30)2.91
(2.73-3.10)4.25
(4.03-4.50)5.43
(5.16-5.71)6.61
(6.30-6.95)7.82
(7.44-8.21)9.10
(8.63-9.58)10.52
(9.92-11.15)11.49
(10.72-12.31)
Preservation 1,5092.26
(1.62-3.15)4.86
(3.89-6.08)7.53
(6.29-8.99)9.57
(8.17-11.20)11.13
(9.60-12.89)12.55
(10.88-14.46)13.85
(12.00-15.97)15.08
(13.00-17.46)17.31
(14.43-20.68)
Sigma HP 3,1421.04
(0.72-1.50)3.17
(2.47-4.06)4.96
(3.84-6.41)6.51
(4.66-9.05)6.51
(4.66-9.05)- - - -
Zimmer Unicompartment
3,7340.52
(0.32-0.85)2.11
(1.62-2.76)3.36
(2.67-4.24)4.69
(3.74-5.87)5.27
(4.15-6.69)5.27
(4.15-6.69)5.27
(4.15-6.69)5.27
(4.15-6.69)5.27
(4.15-6.69)
18 Estimates in blue indicate that fewer than 100 cases remain at risk at the time shown. 19 Brands shown have been used in at least 1,000 primary unicompartmental knee replacement operations.
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Table 3.23 Kaplan-Meier estimates of the cumulative percentage probability of first revision (95% CI) of a total knee replacement at the indicated number of years after primary operation, by main implant brands and type of fixation and constraint20.
Brand 21No. of joints
Cumulative percentage probability of a first revision (95% CI) at time shown if time elapsed since primary operation is
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 years
Advance MPcemented unconstrained, fixed
5,1890.30
(0.18-0.50)1.22
(0.93-1.60)1.61
(1.27-2.06)1.98
(1.58-2.49)2.23
(1.78-2.78)2.96
(2.34-3.73)3.18
(2.51-4.04)3.45
(2.64-4.49)4.03
(2.80-5.76)
AGC
cemented unconstrained, fixed
50,1600.25
(0.21-0.30)0.85
(0.76-0.94)1.32
(1.21-1.43)1.68
(1.55-1.82)1.90
(1.76-2.05)2.24
(2.07-2.41)2.45
(2.26-2.66)2.78
(2.53-3.04)3.07
(2.76-3.41)
Uncemented/hybrid unconstrained, fixed
2,0511.14
(0.76-1.72)2.51
(1.90-3.31)2.91
(2.25-3.77)3.42
(2.66-4.39)3.54
(2.76-4.54)3.99
(3.09-5.14)4.26
(3.25-5.57)4.26
(3.25-5.57)4.26
(3.25-5.57)
Columbus
cemented unconstrained, fixed
4,0510.39
(0.23-0.67)1.39
(1.02-1.89)1.85
(1.40-2.45)2.29
(1.74-3.00)2.68
(2.02-3.57)3.14
(2.29-4.30)4.38
(2.41-7.91)4.38
(2.41-7.91)-
E-Motion Bicondylar Knee
Uncemented/hybrid unconstrained, mobile
1,4160.89
(0.51-1.56)1.50
(0.95-2.34)2.08
(1.41-3.08)2.20
(1.50-3.23)2.37
(1.61-3.47)3.26
(2.04-5.20)3.26
(2.04-5.20)- -
Endoplus Bicondylar Knee
cemented unconstrained, fixed
7,4400.75
(0.58-0.97)1.43
(1.18-1.72)1.84
(1.56-2.18)2.21
(1.89-2.59)2.48
(2.12-2.91)2.72
(2.31-3.20)3.05
(2.55-3.65)3.05
(2.55-3.65)3.05
(2.55-3.65)
cemented unconstrained, mobile
4,2350.55
(0.37-0.83)1.11
(0.83-1.48)1.56
(1.22-1.99)1.91
(1.53-2.40)2.19
(1.76-2.71)2.41
(1.95-2.97)2.47
(2.00-3.05)2.47
(2.00-3.05)2.47
(2.00-3.05)
Uncemented/hybrid unconstrained, mobile
1,4460.66
(0.34-1.26)1.14
(0.69-1.89)1.90
(1.27-2.86)2.51
(1.73-3.64)2.65
(1.84-3.83)2.86
(1.98-4.14)2.86
(1.98-4.14)4.23
(2.15-8.26)4.23
(2.15-8.26)
Genesis 2
cemented uncons-trained, fixed
21,9350.32
(0.25-0.41)0.81
(0.69-0.96)1.18
(1.02-1.38)1.62
(1.40-1.87)1.85
(1.60-2.14)2.11
(1.81-2.45)2.16
(1.85-2.53)2.27
(1.90-2.71)2.27
(1.90-2.71)
cemented posterior stabilised, fixed
6,7360.79
(0.59-1.05)1.48
(1.18-1.85)2.02
(1.64-2.49)2.54
(2.08-3.10)2.80
(2.27-3.46)2.80
(2.27-3.46)2.80
(2.27-3.46)2.80
(2.27-3.46)2.80
(2.27-3.46)
Genesis 2 Oxinium
cemented uncons-trained, fixed
3,2590.47
(0.28-0.79)1.03
(0.71-1.50)1.93
(1.44-2.58)2.25
(1.70-2.97)3.04
(2.31-3.99)3.35
(2.53-4.42)3.73
(2.80-4.96)4.08
(2.99-5.57)4.08
(2.99-5.57)
Insall-Burstein 2
cemented posterior stabilised, fixed
1,8690.33
(0.15-0.72)0.66
(0.38-1.16)1.35
(0.91-2.01)2.01
(1.44-2.78)2.43
(1.79-3.29)2.68
(2.00-3.60)3.10
(2.33-4.13)3.48
(2.59-4.67)3.48
(2.59-4.67)
Kinemax
Cemented uncons-trained, fixed
10,6560.25
(0.17-0.36)1.05
(0.88-1.27)1.78
(1.54-2.05)2.22
(1.95-2.53)2.69
(2.39-3.03)3.03
(2.71-3.40)3.51
(3.14-3.92)3.94
(3.52-4.40)4.28
(3.79-4.83)
LCS
Uncemented/hybrid uncons-trained, mobile
1,3560.74
(0.40-1.38)1.12
(0.67-1.85)1.80
(1.21-2.67)2.11
(1.46-3.04)2.35
(1.66-3.32)2.35
(1.66-3.32)2.43
(1.72-3.42)2.43
(1.72-3.42)2.43
(1.72-3.42)
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Continued >
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177www.njrcentre.org.uk
Brand 21No. of joints
Cumulative percentage probability of a first revision (95% CI) at time shown if time elapsed since primary operation is
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 years
LCS Complete
cemented unconstrained, mobile
8,0650.39
(0.28-0.56)0.93
(0.73-1.18)1.56
(1.28-1.89)2.31
(1.94-2.74)2.77
(2.33-3.29)3.07
(2.57-3.66)3.37
(2.74-4.15)3.37
(2.74-4.15)-
Uncemented/hybrid uncons-trained, mobile
10,0490.54
(0.41-0.71)1.32
(1.09-1.58)1.84
(1.57-2.17)2.21
(1.89-2.56)2.53
(2.17-2.96)2.75
(2.34-3.22)2.95
(2.48-3.52)2.95
(2.48-3.52)-
Maxim
cemented unconstrained, fixed
1,3150.08
(0.01-0.57)0.59
(0.28-1.23)1.33
(0.80-2.19)1.75
(1.12-2.74)2.12
(1.40-3.22)2.12
(1.40-3.22)2.85
(1.87-4.35)3.30
(2.10-5.16)4.51
(2.43-8.29)
MRK
cemented unconstrained, fixed
5,4390.27
(0.16-0.46)0.78
(0.56-1.08)1.34
(1.03-1.73)1.65
(1.30-2.11)1.76
(1.38-2.25)1.86
(1.44-2.39)1.86
(1.44-2.39)3.38
(1.77-6.41)3.38
(1.77-6.41)
Natural Knee II
cemented unconstrained, fixed
2,3940.36
(0.18-0.71)0.94
(0.61-1.46)1.41
(0.97-2.04)1.75
(1.24-2.46)2.14
(1.55-2.95)2.37
(1.72-3.25)2.37
(1.72-3.25)2.37
(1.72-3.25)2.37
(1.72-3.25)
Nexgen
cemented uncons-trained, fixed
29,3770.25
(0.20-0.32)0.66
(0.57-0.78)1.10
(0.96-1.25)1.41
(1.24-1.59)1.65
(1.46-1.87)2.00
(1.75-2.28)2.18
(1.88-2.52)2.44
(2.03-2.93)2.44
(2.03-2.93)
posterior stabilised, fixed
36,6510.43
(0.37-0.51)0.94
(0.84-1.05)1.44
(1.30-1.58)1.84
(1.68-2.02)2.37
(2.17-2.58)2.65
(2.43-2.89)2.99
(2.73-3.28)3.38
(3.04-3.76)3.62
(3.20-4.11)Uncemented/hybrid uncons-trained, fixed
4,5390.53
(0.35-0.79)1.43
(1.11-1.84)2.08
(1.68-2.57)2.42
(1.98-2.96)2.76
(2.27-3.35)2.88
(2.37-3.50)2.96
(2.43-3.61)2.96
(2.43-3.61)3.27
(2.53-4.22)
posterior stabilised, fixed
1,4840.21
(0.07-0.66)1.02
(0.59-1.75)1.58
(1.01-2.47)1.84
(1.19-2.83)2.32
(1.53-3.50)2.32
(1.53-3.50)3.01
(1.92-4.71)3.86
(2.22-6.66)3.86
(2.22-6.66)
Opetrak
cemented posterior stabilised, fixed
1,4940.69
(0.37-1.28)2.27
(1.59-3.23)2.66
(1.90-3.71)3.40
(2.48-4.64)4.07
(2.99-5.52)4.58
(3.35-6.25)4.58
(3.35-6.25)4.58
(3.35-6.25)4.58
(3.35-6.25)
PFC Sigma Bicondylar Knee
Cemented unconstrained, fixed
115,4730.33
(0.30-0.37)0.79
(0.74-0.85)1.14
(1.07-1.21)1.39
(1.31-1.48)1.61
(1.52-1.70)1.77
(1.67-1.87)1.93
(1.81-2.05)2.12
(1.98-2.27)2.18
(2.03-2.35)
unconstrained, mobile
6,5040.61
(0.45-0.84)1.26
(1.01-1.58)1.89
(1.56-2.29)2.18
(1.82-2.62)2.47
(2.06-2.96)2.59
(2.15-3.11)2.79
(2.29-3.40)2.79
(2.29-3.40)2.79
(2.29-3.40)posterior stabilised, fixed
51,7060.37
(0.32-0.43)0.91
(0.83-1.01)1.39
(1.28-1.51)1.67
(1.54-1.81)1.96
(1.81-2.12)2.10
(1.94-2.27)2.31
(2.12-2.51)2.44
(2.22-2.67)2.79
(2.43-3.21)
posterior stabilised, mobile
5,3460.70
(0.50-0.98)1.62
(1.29-2.04)2.31
(1.89-2.81)2.90
(2.41-3.50)3.27
(2.72-3.94)3.67
(3.03-4.44)4.00
(3.25-4.92)4.00
(3.25-4.92)7.10
(3.00-16.28)
all polyethylene tibia
4,1480.33
(0.18-0.60)0.59
(0.35-0.98)1.31
(0.85-2.00)1.43
(0.94-2.19)2.59
(1.64-4.08)2.59
(1.64-4.08)2.59
(1.64-4.08)2.59
(1.64-4.08)2.59
(1.64-4.08)
Constraint unknown
1,6180.26
(0.10-0.68)0.88
(0.51-1.51)1.61
(1.06-2.44)1.89
(1.28-2.80)2.31
(1.58-3.37)2.31
(1.58-3.37)2.57
(1.73-3.79)2.57
(1.73-3.79)2.57
(1.73-3.79)Uncemented/hybrid uncons-trained, fixed
1,6180.31
(0.13-0.75)0.57
(0.30-1.10)1.07
(0.65-1.74)1.30
(0.83-2.04)1.58
(1.04-2.40)1.58
(1.04-2.40)1.58
(1.04-2.40)1.58
(1.04-2.40)1.58
(1.04-2.40)
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Table 3.23 (continued)
Continued >
178 www.njrcentre.org.uk
Brand 21No. of joints
Cumulative percentage probability of a first revision (95% CI) at time shown if time elapsed since primary operation is
1 year 2 years 3 years 4 years 5 years 6 years 7 years 8 years 9 years
Profix
Uncemented/hybrid uncons-trained, fixed
2,2730.23
(0.09-0.54)0.80
(0.50-1.28)1.02
(0.66-1.55)1.20
(0.81-1.80)1.29
(0.87-1.91)1.29
(0.87-1.91)1.29
(0.87-1.91)1.29
(0.87-1.91)2.11
(0.95-4.67)
Rotaglide
cemented uncons-trained, fixed
1,0180.11
(0.01-0.75)0.50
(0.19-1.32)1.58
(0.87-2.85)1.99
(1.15-3.45)2.59
(1.53-4.38)3.12
(1.80-5.37)3.89
(2.17-6.92)3.89
(2.17-6.92)3.89
(2.17-6.92)
Rotaglide +
cemented uncons-trained, mobile
1,6880.42
(0.20-0.84)1.65
(1.13-2.39)2.63
(1.95-3.54)3.19
(2.43-4.19)3.35
(2.56-4.38)3.74
(2.88-4.85)4.00
(3.09-5.18)4.16
(3.21-5.39)4.52
(3.40-6.01)
Scorpio
cemented unconstrained, fixed
15,7400.39
(0.31-0.51)1.13
(0.97-1.32)1.72
(1.51-1.96)2.14
(1.90-2.41)2.44
(2.17-2.74)2.73
(2.43-3.07)3.16
(2.79-3.57)3.34
(2.93-3.82)3.52
(3.00-4.13)
unconstrained, mobile
1,1620.26
(0.08-0.80)1.59
(1.00-2.51)2.40
(1.65-3.48)3.13
(2.24-4.36)3.60
(2.60-4.97)3.97
(2.81-5.59)3.97
(2.81-5.59)3.97
(2.81-5.59)3.97
(2.81-5.59)posterior stabilised, fixed
9,9480.29
(0.20-0.42)1.07
(0.87-1.30)1.62
(1.37-1.91)1.94
(1.66-2.27)2.36
(2.03-2.73)2.63
(2.27-3.06)2.85
(2.43-3.33)2.95
(2.50-3.48)2.95
(2.50-3.48)
posterior stabilised, mobile
1,3720.37
(0.15-0.89)0.99
(0.57-1.70)1.48
(0.95-2.31)1.91
(1.28-2.84)2.12
(1.44-3.10)2.25
(1.54-3.28)2.44
(1.67-3.56)2.44
(1.67-3.56)4.71
(1.80-12.02)
Uncemented/hybrid uncons-trained, fixed
4,7120.59
(0.40-0.86)1.34
(1.04-1.73)1.64
(1.30-2.07)1.78
(1.42-2.23)2.13
(1.71-2.66)2.26
(1.81-2.83)3.29
(2.52-4.29)3.45
(2.64-4.52)3.97
(2.81-5.60)
Triathlon
cemented unconstrained, fixed
22,3530.38
(0.30-0.48)0.94
(0.79-1.11)1.48
(1.27-1.72)1.76
(1.50-2.05)1.83
(1.56-2.15)2.03
(1.67-2.47)2.91
(1.81-4.66)2.91
(1.81-4.66)-
posterior stabilised, fixed
6,4830.51
(0.35-0.73)1.24
(0.96-1.60)1.47
(1.15-1.89)1.95
(1.45-2.61)2.10
(1.54-2.87)2.10
(1.54-2.87)- - -
Vanguard
cemented unconstrained, fixed
14,1850.33
(0.24-0.46)0.91
(0.72-1.14)1.52
(1.23-1.88)2.04
(1.63-2.55)2.48
(1.94-3.18)2.81
(2.05-3.84)3.82
(2.17-6.69)3.82
(2.17-6.69)-
posterior stabilised, fixed
1,9320.53
(0.26-1.06)1.08
(0.63-1.84)1.89
(1.17-3.06)2.49
(1.52-4.07)2.49
(1.52-4.07)2.49
(1.52-4.07)- - -
20 Estimates in blue indicate that fewer than 100 cases remain at risk at the time shown. 21 Brands shown have been used in at least 1,000 primary knee replacement operations for that type of fixation and bearing type.
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Table 3.23 (continued)
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
179www.njrcentre.org.uk
Table 3.24 Age and gender distribution of patients undergoing all types of primary knee replacement operations for the period 2003 to 2012.
Gender Number of patients PercentageFemale
Under 55 23,576 4.1
55-59 29,001 5.0
60-64 47,426 8.2
65-69 57,169 9.8
70-74 63,898 11.0
75-79 59,293 10.2
80 and above 50,660 8.7
Male
Under 55 16,887 2.9
55-59 22,126 3.8
60-64 41,468 7.1
65-69 48,537 8.4
70-74 49,842 8.6
75-79 41,114 7.1
80 and above 30,256 5.2
Total 581,253 100.0
Table 3.25 shows the Kaplan-Meier estimated cumulative percentage probability of a patient dying at the indicated number of years after surgery stratified by age group and gender. Males, particularly in the
older age groups, had a higher cumulative percentage probability of dying in the short or longer term after their primary knee replacement operation.
3.3.5 Mortality after primary knee surgery
This section gives the cumulative likelihood of a patient dying at different lengths of time after their primary operation date by age and gender. Cumulative probabilities of a knee replacement patient dying in the short term (by 30 days or 90 days after the primary operation) and in the longer term, up to nine years after their primary operation, are shown. For simplicity here, we do not take into account whether the patient had further operations (i.e. revision of any primary joint) after the primary operation in calculating the cumulative probability of death.
Of the 589,028 records of a primary operation to replace a knee joint over the period 1 April 2003 to 31 December 2012, 181 not did have an NHS number therefore the death details could not be traced. A further 22 had missing age (19) or gender (3). Amongst the remainder, 7,572 were bilateral operations, having
both knees replaced on the same day. Patients identified as having a bilateral operation have had the second recorded joint excluded from the sample used for mortality analysis.
This identified a sample of 581,253 distinct patients who had had a primary operation to replace one or both knees within the NJR data collection and follow up period. Analysis of the cumulative likelihood of a patient dying in the short or medium term after the primary knee surgery are based on this sample of patients. In total, 43,155 deaths were linked to this set of patients over the time period.
Table 3.24 shows, by gender, the age distribution of patients who underwent primary TKR or UKR surgery over the data collection period. Fewer men than women, overall, have had a primary knee replacement and, proportionally, more women than men undergo surgery above the age of 75.
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Tab
le 3
.25
Kap
lan-
Mei
er e
stim
ated
cum
ulat
ive
perc
enta
ge p
roba
bilit
y (9
5% C
I) of
a p
atie
nt d
ying
at t
he in
dica
ted
num
ber
of y
ears
afte
r a
prim
ary
knee
join
t rep
lace
men
t ope
ratio
n (i)
by
age
grou
p an
d ge
nder
and
(ii)
for
all p
atie
nts.
By
gen
der
an
d a
ge
gro
upN
o. o
f p
atie
nts
Cum
ulat
ive
per
cent
age
pro
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© National Joint Registry 2013
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
181www.njrcentre.org.uk
3.3.6 Conclusions
The data shows some strong trends that merit further discussion. We hope that this will provoke debate and encourage surgeons and manufacturers to re-evaluate their practice in light of the evidence provided. We accept that the data are open to other interpretations and we welcome this. Once again, we must stress very strongly that the NJR provides only part of the picture, that of survivorship, and only survivorship of a short- to medium-term duration; and now for the first time some Patient Related Outcome Measures (PROMs). We do not know whether these trends will continue in the longer term. Indeed, one of the lessons that we have learnt is that survivorship is not linear. Moreover, the data are imperfect and we are reliant on surgeons completing the data accurately and recording every procedure without exception. Some data fields continue to be poorly completed making meaningful analysis difficult.
Unlike hip arthroplasty, the practice of knee arthroplasty has not changed significantly over the past eight years. This year’s analysis shows a continuation of the trends shown previously with total knee replacements surviving markedly better than partial knee replacements.
Overall, the data show that short to medium-term survivorship is excellent after almost all common types of total knee replacement regardless of fixation, constraint and bearing type. For the first time we report on PROMs data. This shows that all types of total knee replacement give significant improvement in the majority of patients (see section 3.5).
For bicondylar knee replacements, unconstrained implants tended to have slightly lower revision rates than posterior cruciate-stabilised implants while mobile bearing prostheses tended to have a slightly higher failure rate than fixed bearing prostheses. Thus, the lowest revision rates were associated with a cemented, unconstrained, fixed bearing prosthesis. However, these differences are small and the results in all these groups are acceptable. This also holds true for analysis within brands. This year the brand analysis has been extended to more brands as more have reached the threshold number of cases needed to do this.
Patello-femoral joint replacements have a very high failure rate and were typically revised for pain. However, it should be remembered that patello-femoral joint replacements are undertaken for different reasons than total knee replacements and so a direct comparison of revision rates would be erroneous. Patello-femoral joint replacements may be revised to a total knee replacement because of problems with a different part of the knee and so the reason for revision may be unrelated to the original procedure. In addition, there may be reasons related to the aetiology of patello-femoral arthritis that could explain why replacing the joint, without significantly correcting the underlying biomechanical cause, may not always be a successful strategy. Patello-femoral joints lead to a significant improvement in PROMs, but the improvement is not as marked as with unicondylar and total knee replacements.
Unicondylar knee replacements also have a higher failure rate than total knee replacements. They were commonly revised for pain and loosening. Again, unicondylar knee replacements may be undertaken for different reasons than total knee replacements and they may be revised to a total knee replacement because of disease progression in a non-operated compartment which is unrelated to the original procedure. Therefore, comparing revision rates with total knee replacements is not straightforward. The improvement in PROMs after unicondylar knee replacement is very similar to that achieved by total knee replacement.
We report mortality after knee replacement using slightly different methodology to last year. Once again we show that knee replacement is associated with a slightly lower risk of death compared to hip replacement. We are currently conducting an in-depth study of post-operative mortality.
3.4 Outcomes after primary ankle replacement
Part 3
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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3.4.1 Overview of primary ankle surgery
This section looks at revision and mortality for all primary ankle operations performed up to 31 December 2012.
There were 1,417 primary operations (see Tables 3.1 and 3.2), including two bilateral operations performed at the same time.
Table 3.26 summarizes the procedures by year of primary operation;
Table 3.26 Number of primary ankle operations by year.
Year of primary Number of procedures2008 3
2009 5
2010 388
2011 505
2012 516
Total 1,417
Table 3.27 Number of primary ankles by ankle brand.
Brand Number (%) Mobility 800 (56.5)
Zenith 280 (19.8)
Box 91 (6.4)
Salto 86 (6.1)
Star 69 (4.9)
Hintegra 56 (4.0)
Rebalance 17 (1.2)
Inbone 2 (0.1)
Taric 1 (0.1)
Not known 15 (1.1)
Total 1,417 (100)
The median age at primary surgery was 67 years (IQR 61 to 74 years) and, overall, the ages of those having a first replacement of an ankle joint ranged between 24 and 91 years. Men made up 57.2% of all who underwent primary ankle replacement surgery.
All procedures were uncemented apart from two in which both cemented talar and tibial components were recorded and a further four for which there was either no component data, or the data were inconsistent.
The procedures were carried out by 165 consultants; 44 (27%) of them performed 10 or more procedures.
The maximum number of procedures carried out by any consultant was 102.
Similarly the total number of units involved was 175; 37 (21%) of them carried out 10 or more procedures. The maximum number of procedures carried out by any unit was 94.
Table 3.27 below shows the distribution of ankle brands. Mobility was the main brand used (56.5% of procedures) followed by Zenith (19.6%).
© N
atio
nal J
oint
Reg
istr
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13©
Nat
iona
l Joi
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2013
184 www.njrcentre.org.uk
3.4.2 Revisions after primary ankle surgery
The maximum follow up time available was 4.63 years and, up to the end of December 2012, only nine revisions of the primary ankle implant had been recorded in the NJR. Estimated cumulative percentage
probabilities of revision (based on Kaplan-Meier estimates) at 30 days, 90 days, 1 year and 2 years, respectively, were: 0.07% (95% CI: 0.01%-0.50%), 0.14% (95% CI: 0.04%-0.58%), 0.24% (95% CI: 0.08%-0.74%) and 1.40% (95% CI: 0.69%-2.83%).
Table 3.28 below lists the stated reasons for the nine revisions.
Table 3.28 Reasons for ankle revision (not mutually exclusive).
Reason Number Infection
High suspicion (e.g. pus or confined micro) 0
Low suspicion (awaiting micro/histology) 4
Aseptic loosening
Tibial component 2
Talar component 0
Lysis
Tibia 1*
Talus 1*
Malalignment 2
Implant fracture
Tibial component 0
Talar component 1
Meniscal component 0
Wear of polyethylene component 0
Meniscal insert dislocation 0
Component migration/Dissociation 1
Pain (undiagnosed) 1
Stiffness 0
Soft tissue impingement 1
Other indication for revision 2
*Same patient had both of these reasons.
3.4.3 Mortality after primary ankle surgery
There were 17 deaths in total. The estimated cumulative percentage probability of death (using
Kaplan-Meier) at 30 days, 90 days, 1 year and 2 years were, respectively: 0.0%, 0.15% (95% CI: 0.04%-0.59%), 1.05% (95% CI: 0.59%-1.85%) and 1.49% (95% CI: 0.88%-2.51%) There were too few deaths for further breakdown by age and gender.
© N
atio
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National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
185www.njrcentre.org.uk
Annexe to survival analysis
In a departure from our previous reports, in the tables above, we have used Kaplan-Meier estimates for the cumulative probability of failure (i.e. where failure is either a revision or death) at given times t, F(t). Previously we had reported Nelson-Aalen estimates of the ‘cumulative hazard’ (also called ‘integrated hazard’).
This change in reported values brings us more in line with the form of reporting undertaken by other National Registries and, therefore, makes for easier comparison with published work from these and other research bodies.
The cumulative hazard at time t after primary operation, say H(t), is not the same as the cumulative probability of failure, F(t). To understand H(t), first start with the concept of the ‘hazard rate’ (analogous to the ‘force of mortality’ used in actuarial science). In the case of revision, the hazard rate at time t is the (instantaneous) rate at which revisions are performed amongst those cases that have not been revised previously. For discrete observations over time, the cumulative hazard at time t is the cumulative sum of the hazard rates; in continuous time it is the area under (i.e. the integral of) the hazard rate curve. The cumulative hazard here is estimated from the data using Nelson-Aalen estimates to account for the discrete time nature of observations.
Although the ‘cumulative hazard’ (H(t)) and ‘cumulative probability of failure’ (F(t)) are estimated using different approaches, they are mathematically related through the expression F(t)=(1 - e (-H(t))) and so it is possible to estimate one using an estimate of the other. Where
failure rates are less than 10%, the numerical value of e (-H(t)) is numerically close to the value of 1-H(t) and therefore F(t) is close to H(t). The values of F(t) and H(t) do not remain numerically similar once failure rates exceed 10% and then, in general, H(t) will be greater than F(t). This has become particularly noticeable in the NJR data set for mortality where, after nine years, the estimate of H(t) for 80+ year old men now has exceeded 100 (expressed as number of deaths per 100), whereas, because F(t) is a probability, its value cannot exceed 100%.
It is useful to use cumulative hazards for plotting, e.g. to compare revision rates for various sub-groups. As with the cumulative probability of failure, groups with greater cumulative hazards will have the highest revision rates. The shape of each cumulative hazard curve, however, carries useful information about how the revisions occur because the gradient of the curve at any time t estimates the hazard rate. If the plot of the cumulative hazard against time is a straight line, then revisions will have occurred at a constant rate throughout, i.e. the revision rate is independent from time of operation. If the graph increases exhibiting a concave shape, then the risk of revision will be lower initially, increasing with time after operation. The converse is true; if the shape is convex, revision rate would be higher initially.
For the above reasons we give Kaplan-Meier estimates in the tables but have retained estimates of ‘cumulative hazards’ for plotting.
3.5 PROMs outcomes
Part 3
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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3.5.1 Background to Patient Reported Outcome Measures (PROMs)
PROMs assess the patient’s experience and perspective of the quality of care and treatment they receive when they undergo a NHS-funded hip and/or knee replacement. PROMs are collected via pre- and post-operative questionnaires; the items allow the patient to self report on their state of health and general lifestyle before and after their joint replacement surgery. These outcomes provide a means of determining the impact the procedure has subsequently had on their quality of life. PROMs have been routinely collected by all providers of NHS-funded care in England since April 2009. The initial questionnaire, Q1, is normally administered just prior to the operation and questionnaire Q2 approximately six months following the operation. Additional information is available from: http://www.hscic.gov.uk/PROMs
In this section we have concentrated on the variables that described health benefits following primary hip or knee replacement.
3.5.2 Data linkage from PROMs to HES to NJR
Our base PROMs data file had 445,134 entries (207,436 hips and 230,429 knees).
Q1 and Q2 had already been linked together when received by the NJR.
Linkage between PROMs and the NJR data set could only be made via Hospital Episode Statistics (HES) data spanning the same time period as the PROMs data set.
PROMs to HES matching:
A total of 3% of the PROMs entries had no HES patient identifier (HESID) and a further 24% of the remainder could not be matched to a particular episode in HES (via EPIKEY). Of the remaining 326,876 PROMs entries, there were 2,653 duplicate matches and 16 triplicate matches to HES, meaning that multiple PROMs entries existed for the same HES patient episode. For these multiple matches, we chose the ‘best match’, i.e. the PROMs entry that had the best episode matched rank. In 234 cases there were two equal best matches; we gave priority then to the 144 PROMs entries that were
complete but it was not possible to choose the ‘higher quality’ record from the remaining 90 multiple entries and so these were omitted. This left 324,101 PROMs entries, some of which related to primary and some to revision procedures.
HES to NJR matching:
Within the HES data set, seven rankings were available resulting from linkage methods designed to determine the most likely NJR operation identifier for a given patient/episode in HES. The linkage method utilises and ranks the availability of various combinations of patient information associated with a particular HES episode. Relevant patient related information included patient NHS number, date of episode/entry, provider code, local patient ID, date or year of birth and patient gender. In addition, an episode in HES must have an ‘orthopaedically relevant’ OPCS procedure code associated with the particular episode i.e. OPCS codes must identify an orthopaedic type of event. The linkage rankings were used to assign the most probable NJR operation number to the HES person ID (HESID) and episode (EPIKEY).
Not all of such ‘orthopaedically relevant’ HES episodes had entries in the NJR. However, of the 517, 220 HES entries between 2003 and 2012 we were able to assign 391,240 (75.6%) to an NJR procedure.
PROMs/HES to NJR/HES matching:
Finally, we were able to link 274,729 of the above 324,101 PROMs entries to HES patient episodes with an assigned NJR operation identifier. There were some duplications i.e. instances where more than one PROMs entry could be ascribed to the same NJR operation. At this juncture we linked the PROMs data separately to our linked data files for primary hips and knees, after first removing bilateral operations from the latter. Any remaining duplications were removed pragmatically, by checking gender match, NJR patient identifiers and finally by choosing the PROMs entry where the date of completion of Q1 was closest to the date of the operation.
The remainder of this section provides some simple summary statistics for the PROMs entries that could be matched to our unilateral linked primary hip and knee files.
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3.5.3 PROMs outcomes for primary hip replacements
A total of 124,136 of the linked primary hip operations in NJR had an associated PROMs entry; Q1 was complete in 99.7% of these and both Q1 and Q2 were complete in 75.6%. The median (IQR) interval of time from completion of Q1 to the primary operation was 0.59 months (IQR 0.23-1.22; n=84,078) and from primary operation to completion of Q2 was 6.47 months (IQR 6.31 to 6.87; n=83,808).
Table 3.29 opposite shows the overall outcomes after primary hip surgery.
Methodological note
The three health measures in PROMs are the EQ-5D Index, the EQ-5D Health Scale and the Oxford Hip/Knee Scores.
The EQ-5D Index22 is derived from a profile of responses to five questions about health ‘today’, covering activity, anxiety/depression, discomfort, mobility and self care. Weights had been applied to the responses to these questions to calculate the ‘index’. All five questions had to be answered in order to do this. The higher the index the better the patient, with one being the best possible score. The distribution of the EQ-5D Index is such that parametric statistical methods are not suitable for statistical comparison. Non-parametric unpaired and paired comparisons (two-tailed Mann-Whitney and Wilcoxon matched-pairs signed-ranks) have been used here but, because of the ‘ceiling effect’ (scores cannot improve beyond 1), paired comparisons were double-checked with simple sign tests.
The EQ-5D Health Scale is a visual analogue scale (VAS), asking about how the patients rate themselves ‘on the day’ (0=worst, 100=best).
The Oxford Hip/Knee Scores are based on responses to 12 hip or knee specific questions about health ‘in the last four weeks’. Each question is scored from 0 to 4 and the scores are summed to give a score from 0 (worst) to 48 (best). If fewer than three responses to individual questions are missing, they can be replaced by the mean of the remaining questions.
The VAS was not normally distributed, neither were the Oxford Hip and Knee scores at Q2; non-parametric methods of comparison, therefore, were used for both these variables.
Summary statistics used throughout this section are the median and Inter-Quartile Ranges (IQRs). The latter is less sensitive to outliers than a simple range. (Note however that, for paired data, the median difference may not be equal to the difference in medians.)
22 As the index is bounded between 0 and 1, we present results in this section with respect to the EQ-5D Index to three decimal places for greater precision.
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Table 3.29 Overall outcomes after primary hip surgery.
Variable Frequency (%)Q2 Satisfaction: Satisfaction after the operation (Describe the results of the operation)
1 Excellent 35,313 (38.5%)
2 Very good 32,147 (35.0%)
3 Good 16,826 (18.3%)
4 Fair 5,739 (6.3%)
5 Poor 1,735 (1.9%)
Q2 Success: Problems now compared to before operation
1 Much better 78,617 (85.6%)
2 A little better 8,715 (9.5%)
3 About the same 2,298 (2.5%)
4 A little worse 1,332 (1.5%)
5 Much worse 908 (1.0%)
Q2 Wound: Wound problems since operation
1 Yes 8,498 (10.0%)
2 No 76,070 (90.0%)
Q2 Bleeding: Bleeding since operation
1 Yes 4,797 (5.8%)
2 No 78,165 (94.2%)
Q2 Urine: Urinary problems after the operation
1 Yes 11,260 (13.3%)
2 No 73,302 (86.7%)
Q2 Allergy: Experienced allergy with respect to drugs after the operation
1 Yes 10,022 (11.7%)
2 No 75,813 (88.3%)
Q2 Re-admitted: Re-admitted to hospital since operation
1 Yes 6,726 (7.3%)
2 No 85,120 (92.7%)
Q2 Further Surgery: Has had another operation on affected site
1 Yes 1,924 (2.1%)
2 No 89,998 (97.9%)
Bias in completion of PROMs is difficult to assess because we do not have details of how many PROMs questionnaires were sent out and how many were returned.
Amongst those NJR cases for whom we had PROMs entries, we checked whether those who had available/
complete measures at Q2 tended to have higher or lower scores at Q1; we found that the Q2 completers tended to have had better scores at Q1, as seen in Table 3.30. It may be that some of the initially less healthy group had died in the interim; this will be explored later.
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Table 3.30 Bias in Q2 completion of EQ-5D Index, EQ-5D Health Scale (VAS), Oxford Hip Score.
Measure Was measure available and complete at Q2?Median (IQR)
of the score at Q1EQ-5D Index
Yes 83,202 0.516 (0.055 to 0.656)
No 33,607 0.159 (-0.016 to 0.620)
P<0.001*
EQ-5D Health Scale (VAS)
Yes 80,394 70 (50-80)
No 31,513 65 (50-80)
P<0.001*
Oxford Hip Score
Yes 92,133 18 (12-24)
No 30,872 15 (10-22)
P<0.001*
*Mann-Whitney U-test
Completion rates for both EQ-5D Index and EQ-5D Health Scale (VAS) tended to be slightly higher in men than in women at both Q1 and Q2. The differences, although ‘statistically significant’, were in fact very small (e.g. for VAS at Q1: completion rates were 91.5% versus 89.3%, respectively, for men and women).
Significant improvements from Q1 to Q2 were seen in all three health measures overall (see Tables 3.31 to 3.33).
Histograms showing comparative distributions of EQ-5D Scale (VAS) and Oxford Hip Scores at Q1 and Q2 for complete pairs are shown in Figures 3.8 and 3.9 respectively.
All hip sub-groups showed significant improvement in EQ-5D Index (Table 3.31).
All the main sub-groups showed improvements in the VAS (Table 3.32) and in the Oxford Hip Score (Table 3.33).
Table 3.31 Changes in EQ-5D Index for hip primaries with index scores at both time points.
EQ-5D Index Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All cases 83,2020.516
(0.055-0.656)0.796
(0.691-1)0.380
(0.175-0.694)P<0.001
All cemented 27,3290.364
(0.030-0.620)0.796
(0.639-1)0.413
(0.162-0.694)P<0.001
Cemented by bearing surface:
MoP 23,4820.293
(0.030-0.620)0.779
(0.623-1)0.413
(0.159-0.694)P<0.001
MoM 740.516
(0.055-0.620)0.805
(0.639-1)0.309
(0.159-0.633)P<0.001
CoP 2,8840.516
(0.055-0.656)0.796
(0.691-1)0.380
(0.177-0.697)P<0.001
Others/unsure 8890.516
(0.055-0.691)0.848
(0.691-1)0.380
(0.192-0.684)P<0.001
*Wilcoxon matched-pairs signed-ranks test and checked with sign test. **Sign test.
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Continued >
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*Wilcoxon matched-pairs signed-ranks test and checked with sign test. **Sign test.
EQ-5D Index Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All uncemented 38,6930.516
(0.055-0.691)0.814
(0.691-1)0.380
(0.176-0.691)P<0.001
Uncemented by bearing surface:
MoP 15,0540.516
(0.055-0.691)0.814
(0.691-1)0.380
(0.176-0.694)P<0.001
MoM 2,0490.516
(0.055-0.691)0.815
(0.691-1)0.344
(0.165-0.661)P<0.001
CoP 5,3280.516
(0.055-0.689)0.796
(0.689-1)0.380
(0.181-0.694)P<0.001
CoC 15,1750.516
(0.055-0.691)0.848
(0.691-1)0.380
(0.192-0.672)P<0.001
CoM 5140.587
(0.088-0.691)0.796
(0.691-1)0.309
(0.123-0.535)P<0.001
Others/unsure 5730.516
(0.055-0.620)0.796
(0.620-1)0.377
(0.105-0.694)P<0.001
All hybrid 13,0140.516
(0.055-0.656)0.814
(0.691-1)0.413
(0.192-0.697)P<0.001
Hybrids by bearing surface:
MoP 8,8290.516
(0.055-0.620)0.812
(0.691-1)0.413
(0.192-0.705)P<0.001
MoM 880.516
(0.025-0.620)0.850
(0.701-1)0.413
(0.235-0.649)P<0.001
CoP 1,6020.516
(0.055-0.656)0.848
(0.691-1)0.396
(0.204-0.695)P<0.001
CoC 2,2910.516
(0.055-0.689)0.850
(0.691-1)0.380
(0.192-0.697)P<0.001
Others/unsure 2040.516
(0.055-0.673)0.796
(0.691-1)0.388
(0.198-0.667)P<0.001
All reverse hybrid 2,4790.260
(-0.003 to 0.620)0.779
(0.620-1)0.413
(0.159-0.707)P<0.001
Reverse hybrids by bearing surface:
MoP 1,6360.260
(-0.003 to 0.620)0.779
(0.620-1)0.413
(0.140-0.708)P<0.001
CoP 8310.260
(-0.003 to 0.620)0.796
(0.620-1)0.413
(0.173-0.703)P<0.001
Others/unsure 120.209
(0.026-0.568)0.760
(0.587-0.908)0.404
(0.202-0.613)P=0.003
(P=0.002**)All resurfacing
MoM 1,6870.587
(0.189-0.691)1 (0.743-1)
0.309 (0.165-0.484)
P<0.001
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Table 3.31 (continued)
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Table 3.32 Changes in EQ-5D Health Scale Score (VAS) for hip primaries with scores at both time points.
EQ-5D Health Scale Score (VAS) Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All cases* 80,394 70 (50-80)
80 (69-90)
9 (-2 to 20) P<0.001
All cemented 26,339 70 (50-80)
80 (65-90)
6 (-5 to 20) P<0.001
Cemented by bearing surface:
MoP 22,556 70 (50-80)
80 (65-90)
6 (-5 to 20) P<0.001
MoM 74 72.5 (50-80)
85 (60-90)
0.5 (-4 to 19) P=0.009
CoP 2,823 70 (50-80)
80 (70-90)
10 (0 to 25) P<0.001
Others/unsure 886 72.5 (59-85)
80 (70-90)
5 (-3 to 20) P<0.001
All uncemented 37,451 70 (50-80)
80 (70-90)
10 (-1 to 22) P<0.001
Uncemented by bearing surface:
MoP 14,385 70 (50-80)
80 (70-90)
6 (-4 to 20) P<0.001
MoM 1,958 70 (51-80)
80 (70-90)
9 (-2 to 20) P<0.001
CoP 5,170 70 (50-80)
80 (70-90)
10 (-1 to 25) P<0.001
CoC 14,879 70 (50-80)
80 (70-90)
10 (0 to 25) P<0.001
CoM 505 70 (50-83)
80 (70-90)
10 (-2 to 20) P<0.001
Others/unsure 554 70 (50-80)
80 (65-90)
10 (-1 to 21) P<0.001
All hybrid 12,564 70 (50-80)
80 (70-90)
10 (-1 to 22) P<0.001
Hybrids by bearing surface:
MoP 8,450 70 (50-80)
80 (68-90)
8 (-3 to 20) P<0.001
MoM 83 70 (50-80)
80 (70-90)
10 (0 to 25) P<0.001
CoP 1,567 70 (50-80)
80 (70-90)
10 (0 to 25) P<0.001
CoC 2,254 70 (50-80)
80 (70-90)
10 (0 to 25) P<0.001
Others/unsure 210 70 (50-80)
80 (65-90)
5 (0 to 20) P<0.001
All reverse hybrid 2,378 70 (50-80)
80 (64-90)
9 (-3 to 21) P<0.001
Reverse hybrids by bearing surface:
MoP 1,561 70 (50-80)
80 (65-90)
8 (-5 to 20) P<0.001
CoP 806 70 (50-80)
80 (60-90)
10 (0 to 25) P<0.001
Others/unsure 11 60 (33-70)
55 (40-90)
0 (-18 to 20) P=0.65
All resurfacing
MoM 1,662 70 (57-85)
85 (75-90)
10 (0-20) P<0.001
*Wilcoxon matched-pairs signed-ranks test.
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Table 3.33 Changes in Oxford Hip Score for hip primaries with scores at both time points.
Oxford Hip Score Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All cases 92,133 18 (12-24)
41 (34-46)
21 (14-28) P<0.001
All cemented 30,551 17 (11-23)
40 (32-45)
21 (14-27) P<0.001
Cemented by bearing surface:
MoP 26,294 17 (11-23)
39 (32-44)
21 (14-27) P<0.001
MoM 83 18 (11-22)
41 (30-46)
21 (12-28) P<0.001
CoP 3,189 17 (12-24)
42 (34-46)
21 (14-28) P<0.001
Others/unsure 985 19 (13-24)
42 (36-46)
21 (15-27) P<0.001
All uncemented 42,497 18 (12-24)
42 (35-46)
21 (14-28) P<0.001
Uncemented by bearing surface:
MoP 16,704 18 (12-24)
42 (34-46)
21 (14-28) P<0.001
MoM 2,240 19 (13-25)
43 (35-46)
21 (14-27) P<0.001
CoP 5,805 18 (12-23)
42 (34-46)
21 (14-28) P<0.001
CoC 16,547 18 (13-24)
43 (36-47)
22 (15-28) P<0.001
CoM 565 20 (14-26)
43 (35-46)
20 (13-27) P<0.001
Others/unsure 636 18 (13-23)
42 (33-46)
21 (14-28) P<0.001
All hybrid 14,493 18 (12-24)
42 (35-46)
22 (15-28) P<0.001
Hybrids by bearing surface:
MoP 9,875 17 (12-24)
41 (34-46)
21 (14-28) P<0.001
MoM 97 18 (13-23)
43 (37-46)
21 (16-27) P<0.001
CoP 1,770 18 (12-24)
43 (36-46)
22 (15-28) P<0.001
CoC 2,516 18 (12-24)
43 (37-47)
23 (15-29) P<0.001
Others/unsure 235 18 (13-23)
41 (34-46)
21 (14-28) P<0.001
All reverse hybrid 2,755 16 (11-23)
40 (32-45)
20 (13-28) P<0.001
Reverse hybrids by bearing surface:
MoP 1,825 16 (11-23)
40 (32-45)
21 (13-27) P<0.001
CoP 918 16 (11-23)
40 (32-45)
20 (14-28) P<0.001
Others/unsure 12 11.5 (10-16.5)
38 (21.5-44)
16.5 (10-28.5) P=0.002
All resurfacing
MoM 1,837 22 (16-28)
44 (38-47)
19 (12-25) P<0.001
*Wilcoxon matched-pairs signed-ranks test.
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Figure 3.8 Histogram to compare the distributions of the EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=80,394). (i) At Q1
(ii) At Q2
5,000
10,000
15,000
Freq
uenc
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0 20 40 60 80 100
Q1 EQ-5D HEALTH SCALE
5,000
0
10,000
15,000
Freq
uenc
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0 20 40 60 80 100
Q2 EQ-5D HEALTH SCALE
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Figure 3.8 Histogram to compare the distributions of the EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=80,394).
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Figure 3.9 Histogram to compare the distributions of the Oxford Hip Score between Q1 and Q2 in cases with scores at both time points (n=92,133). (i) At Q1
(ii) At Q2
5,000
0
15,000
10,000
20,000
Freq
uenc
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Q1 Oxford Hip Score
0 10 20 30 40 50
5,000
0
15,000
10,000
20,000
Freq
uenc
y
Q2 Oxford Hip Score
0 10 20 30 40 50
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Figure 3.9 Histogram to compare the distributions of the Oxford Hip Score between Q1 and Q2 in cases with scores at both time points (n=92,133).
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3.5.4 PROMs outcomes for primary knee replacements
132,019 of the linked primary knee operations in NJR had an associated PROMs entry; Q1 was complete in 99.7% of these and both Q1 and Q2 were complete in 74.6%. The median (IQR) interval of time from
completion of Q1 to the primary operation was 0.56 months (IQR 0.20-1.22; n=86,908) and from primary operation to completion of Q2 was 6.47 months (IQR 6.31 to 6.90; n=87,171).
Table 3.34 below shows the overall outcomes after primary hip surgery.
Table 3.34 Overall outcomes after primary knee surgery.
Variable Frequency (%)Q2 Satisfaction: Satisfaction after the operation (Describe the results of the operation)
1 Excellent 21,962 (22.7%)
2 Very good 33,626 (34.8%)
3 Good 25,185 (26.1%)
4 Fair 12,186 (12.6%)
5 Poor 3,668 (3.8%)
Q2 Success: Problems now compared to before operation
1 Much better 68,540 (70.8%)
2 A little better 17,127 (17.7%)
3 About the same 4,901 (5.1%)
4 A little worse 3,727 (3.8%)
5 Much worse 2,577 (2.7%)
Q2 Wound: Wound problems since operation
1 Yes 11,825 (13.4%)
2 No 76,265 (86.6%)
Q2 Bleeding: Bleeding since operation
1 Yes 6,768 (7.9%)
2 No 78,915 (92.1%)
Q2 Urine: Urinary problems after the operation
1 Yes 10,635 (12.2%)
2 No 76,231 (87.8%)
Q2 Allergy: Experienced allergy with respect to drugs after the operation
1 Yes 12,244 (13.7%)
2 No 76,938 (86.3%)
Q2 Re-admitted: Re-admitted to hospital since operation
1 Yes 9,295 (9.6%)
2 No 87,467 (90.4%)
Q2 Further Surgery: Has had another operation on affected site
1 Yes 3,236 (3.3%)
2 No 93,646 (96.7%)
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Amongst these NJR cases for whom we have PROMs entries, those who had available completed measures at Q2 tended to have had better scores at Q1, see
Table 3.35 below. As for hips, it may be that some of those with poorer scores at Q1 had died before the Q2 assessment.
*Mann-Whitney U-test
Table 3.35 Bias in Q2 completion of EQ-5D Index, EQ-5D Health Scale (VAS), Oxford Knee Score.
Measure Was measure available and complete at Q2?Median (IQR)
of the score at Q1EQ-5D Index
Yes 87,306 0.587 (0.088-0.691)
No 36,451 0.264 (0.055-0.691)
P<0.001*
EQ-5D Health Scale (VAS)
Yes 84,031 70 (55-80)
No 33,999 70 (50-80)
P<0.001*
Oxford Knee Score
Yes 95,353 19 (13-24)
No 35,311 16 (11-22)
P<0.001*
Completion rates for all three health measures, at both Q1 and Q2, tended to be slightly higher in men than women; the differences, although ‘statistically significant’ ,were very small (e.g. 99.0% vs 98.9% respectively at Q1 and 73.5% vs 72.2% at Q2 for the Oxford Knee Score).
Significant improvements from Q1 to Q2 were seen in all three health measures (see Tables 3.36 to 3.38).
The distributions of EQ-5D Scale (VAS) and Oxford Knee Scores at Q1 and Q2 for complete pairs are shown in Figures 3.10 and 3.11.
All knee sub-groups showed significant improvement in EQ-5D Index (Table 3.36).
All sub-groups except patello-femoral showed small improvements in VAS (Table 3.37).
All sub-groups showed improvements in the Oxford Knee score (Table 3.38).
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Table 3.36 Changes in EQ-5D Index for knee primaries with index scores at both time points.
EQ-5D Index Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All cases 87,306 0.587 (0.088-0.691)
0.727 (0.620-0.883)
0.275 (0.069-0.568) P<0.001
All cemented 81,358 0.587 (0.088-0.691)
0.727 (0.620-0.883)
0.280 (0.069-0.568) P<0.001
All uncemented 3,782 0.587 (0.101-0.691)
0.727 (0.620-0.848)
0.240 (0.036-0.532) P<0.001
All hybrid 636 0.587 (0.101-0.691)
0.725 (0.587-0.849)
0.240 (0.036-0.532) P<0.001
All patello-femoral 257 0.620 (0.124-0.691)
0.691 (0.516-0.796)
0.105 (0.000-0.311) P<0.001
All unicondylar 1,273 0.620 (0.159-0.691)
0.760 (0.620-1.000)
0.240 (0.036-0.532) P<0.001
Table 3.37 Changes in EQ-5D Health Scale score (VAS) for knee primaries with scores at both time points.
EQ-5D Health Scale Score (VAS) Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All cases 84,031 70 (55-80)
75 (60-85)
3 (-7 to 15) P<0.001
All cemented 78,239 70 (55-80)
75 (60-85)
3 (-7 to 15) P<0.001
All uncemented 3,681 70 (55-82)
76 (60-86)
4 (-5 to 15) P<0.001
All hybrid 609 70 (60-85)
75 (60-85)
2 (-10 to 15) P<0.001
All patello-femoral 259 70 (50-80)
70 (50-85)
0 (-10 to 15) P=0.16
All unicondylar 1,243 75 (60-85)
80 (65-89)
3 (-9 to 15) P<0.001
Table 3.38 Changes in Oxford Knee Score for knee primaries with scores at both time points.
Oxford Knee Score Number of pairs
Q1 Before operation
Median (IQR)
Q2 After operation
Median (IQR)
Change (Q2 minus Q1)
Median (IQR) P-value*
All cases 93,353 19 (13-24)
36 (28-42)
16 (9-22) P<0.001
All cemented 88,921 19 (13-24)
36 (28-42)
16 (9-22) P<0.001
All uncemented 4,067 19 (14-25)
35 (27-42)
14 (7-21) P<0.001
All hybrid 678 19 (13-24)
35 (26-42)
15 (7-21) P<0.001
All patello-femoral 282 20 (14-25)
32 (22-40)
10 (4-18) P<0.001
All unicondylar 1,405 21 (15-26)
38 (29-44)
15 (8-21) P<0.001
*Wilcoxon matched-pairs signed-ranks test and checked with sign test.
*Wilcoxon matched-pairs signed-ranks test and checked with sign test.
*Wilcoxon matched-pairs signed-ranks test and checked with sign test.
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Figure 3.10 Histogram to compare the distributions of EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=84,031). (i) At Q1
(ii) At Q2
5,000
0
15,000
10,000
Freq
uenc
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Q1 EQ-5D HEALTH SCALE
0 20 40 60 80 100
5,000
0
15,000
10,000
Freq
uenc
y
Q2 EQ-5D HEALTH SCALE
0 20 40 60 80 100
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Figure 3.10 Histogram to compare the distributions of EQ-5D Health Scale Score (VAS) between Q1 and Q2 in cases with scores at both time points (n=84,031).
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Figure 3.11 Histogram to compare the distributions of the Oxford Knee Score between Q1 and Q2 in cases with scores at both time points (n=93,353). (i) At Q1
(ii) At Q2
4,000
3,000
2,000
1,000
0
6,000
5,000
Freq
uenc
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Q1 Oxford Knee Score
0 10 20 30 40 50
4,000
3,000
2,000
1,000
0
6,000
5,000
Freq
uenc
y
Q2 Oxford Knee Score
0 10 20 30 40 50
© N
atio
nal J
oint
Reg
istr
y 20
13©
Nat
iona
l Joi
nt R
egis
try
2013
Figure 3.11 Histogram to compare the distributions of the Oxford Knee Score between Q1 and Q2 in cases with scores at both time points (n=93,353).
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
201www.njrcentre.org.uk
3.5.5 Conclusions
Data linkage via HES allowed a match of PROMs data to the subset of NJR records associated with English patients who had had NHS funded primary hip or knee replacement procedures (from the start of the collection of PROMs in April 2009 until the end of the current NJR annual report review period of 31 December 2012). Over a quarter of the identified orthopaedic HES episodes were lost initially due to the absence of a traceable NHS number. Of the remaining PROMs records, between a quarter and 29% of this group of English NHS funded primary hip/knee replacement patients had only completed the pre-operation survey and so we are unable to report on how this patient group evaluated their quality of life post-operation. In addition, based on the median responses (and IQR) to Q1 for this sub-group compared to those who did complete both surveys, these patients tended to be in a poorer state of health prior to surgery. Therefore, in interpreting the PROMs results for those patients who completed both Q1 and Q2, it should be remembered that these are patients who generally were healthier prior to operation and would have a better prospect of surviving to six months after the primary surgery. Thus, pre- to post-operative changes in PROMs health scores are likely to be less improved with the inclusion of the less healthy pre-operative subset of patients lost to follow up.
The vast majority of the 93,846 hip replacement patients who had responded to both Q1 and Q2 indicated at least a ‘fair’ amount of satisfaction post surgery (98.1%) and over 85% of these reported that the problems they had had living with their hip condition before surgery were ‘much better’ after receiving a hip implant.
It is clear that the hip patient group who completed both Q2 and Q1 tended to be in a better state of health before surgery than those who had only completed Q1 (as indicated by higher scores on all three health measures prior to operation for these; most notably on the EQ-5D Index). Therefore, these patients are more likely to have greater resilience to undergoing surgery and are less likely to be susceptible to complications post surgery. This group reported a significant overall improvement in their
quality of life post surgery. The median improvements in score on the three health scales were 0.38 on the EQ-5D Index, 10 points on the VAS score and 21 points on the Oxford Hip Score respectively.
In general, of the knee surgery patient group who completed both questionnaires, most reported enhanced lifestyle and health benefits post operation. Operation outcomes were rated as a success overall, although the proportion of those who were at least satisfied with the outcomes were lower than the ratings for hip surgery on the same items. That is, more than 96% of knee patients with responses to both Q1 and Q2 said they were at least fairly satisfied with the results of their surgery. In addition, just over 70% of these patients intimated that the problems they were faced with at circa six months post surgery as a result of their knee condition were ‘much better’ having had knee surgery.
As noted already for the hip patient group, the knee patient surgical group who had completed both surveys tended to have higher scores at Q1 and thus were in better health overall compared to the group of Q1 only respondees.
Across all knee surgery cases, for the three knee PROMs measures of interest here, there was marked improvement in patient self-reported well-being and health post operation. This was seen as a general increase in median scores and IQR values after surgery i.e. responses to Q2 only and in the median change in Q1 and Q2 knee health scores of 0.275 on the EQ-5D Index, 3 points on the VAS score and 16 points on the Oxford Knee Score respectively. However, the VAS score increase overall was more moderate than for the other two measures.
The median score change was fairly consistent across the main fixation and knee replacement type sub-groups apart from for those undergoing a patello-femoral type knee surgery. Here, the change in health score ratings compared to the other types of main knee replacement types suggested that post-surgery benefits to health and lifestyle were slightly less improved than for other types of knee replacements.
4.1 Introduction
Part 4Trust-, Local Health Board- and unit-level activity and outcomes 2012
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
203www.njrcentre.org.uk
Part Four shows indicators for hip and knee joint replacement procedures by unit and Trust. This section was first included last year and has been updated as part of the Government’s transparency agenda. It is based on procedures carried out during the 2012 calendar year and submitted to the NJR by 28 February 2013.
Part Four information is based on the actual operation date (1 January to 31 December 2012) whereas data in Part One is based on the date the procedure was submitted (1 April 2012 to 31 March 2013). It is therefore possible for a hospital to have zero submissions in Part Four but not be listed as a nil returner in Part One.
4.2 Unit outlier analysis methodology
Part 4
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
205www.njrcentre.org.uk
Unit outlier analysis covers the period from 1 April 2003 to 31 December 2012.
The outlier analyses made use of funnel plots from statistical process control methodology. These aim to distinguish normal variation between units (which is to be expected) from unusual differences (termed ‘special cause’ variation), which may indicate the need for further investigation. Funnel plots enable units of different sizes to be compared; performance indicators based on smaller numbers of patients will have greater variability and this in turn is reflected by wider control limits.
Summary of the methodology for unit revision rates:
•The standardised revision ratio (SRR) is plotted against the number of expected revisions. The SRR is the total number of revisions divided by the number of expected revisions for that unit’s caseload in respect of the age group, gender, and the diagnosis of the patients. If the SRR is 1, the number of revisions is compatible with the number expected for that unit.
•Control limits for funnel plots are normally set at 95% and 99.8% (roughly equivalent to 2 or 3 standard deviations). Our normal six-monthly review process focuses on those above the upper limit of the latter; one might expect, however, that one in 500 would be outside the 99.8% limits (above or below) just by chance. In the table below we have highlighted in light red (1) units above the upper limit of the 99.8% control limits but also indicate in dark red (2) those that are
much more extreme, i.e. above the upper limit of the 99.99% control limits.
Previous annual reports have discussed in detail how metal-on-metal bearing surfaces are associated with higher revision rates than other bearing surfaces. Many of the outlying hip units identified from this analysis have more commonly used stemmed metal-on-metal and resurfacing procedures, and although use of these implants has now almost ceased in the UK, the higher revision rates for these implants are likely to be reflected in the returns made by these units for some years to come. This may explain their higher revision rates.
Summary of the methodology for unit 90-day mortality rates:
•The standardised mortality ratio (SMR) is plotted against number of expected deaths. The SMR is the number of actual deaths within 90 days of primary joint replacement divided by the number of expected deaths in this period. The number of expected deaths has been calculated after adjustment for patient characteristics (age, gender, and ASA grade of patients). In addition, for hip units, adjustment is made for whether the operation was undertaken for trauma.
•Control limits are as for revisions above.
Any units identified as potential outliers in Part Four have been notified. All units are provided with an Annual Clinical Report and additionally have access to an online NJR Management Feedback system (See section 1.4.6).
Compliance, Consent and Linkability are:
Red if lower than 80%
Amber if equal to or greater than 80% and lower than 95%
Green if 95% or more
• Compliance figures may be low due to delayed data entry• Linkability for some hospitals will be lower than expected if they have private patients from outside England and Wales• Part Four data covers procedures carried out between 1 January 2012 and 31 December 2012
Outlier analyses are:
Light red if units are outside 99.8% control limits (approx 3 standard deviations (SDs))
Dark red if units are outside 99.99% control limits
Please note for the data in following table:
The table uses the following footnotes: 23. Compliance (NHS Trust/Local Health Board Only) - the percentage of cases submitted to the NJR compared to HES/PEDW. 24. Consent Rate - percentage of cases submitted to the NJR with patient consent confirmed. 25. Linkability - the proportion of records which include a valid patient’s NHS number compared with the number of procedures recorded on the NJR. 26. Outliers with respect to 90-day mortality following primary operations performed from 2003 onwards. Units outside 99.8% control limits (approx 3 SDs) are flagged in light red (1); those outside 99.99% control limits are flagged in dark red (2). 27. Outliers with respect to revisions (at any time) following primary operations performed from 2003 onwards. Units outside 99.8% control limits (approx 3 SDs) are flagged in light red (1); those outside 99.99% control limits are flagged in dark red (2).
1
2
206 www.njrcentre.org.uk
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© N
atio
nal J
oint
Reg
istr
y 20
13
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t/Lo
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207www.njrcentre.org.uk
Trus
t/Lo
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20
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ated
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-
90 D
ay
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ay
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ases
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ark
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© N
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Reg
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Bar
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ombe
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89
96%
97%
2.2
40%
70.2
39%
83%
208 www.njrcentre.org.uk
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© N
atio
nal J
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Reg
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13
Trus
t/Lo
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Per
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10A
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bul
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ced
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20
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Per
cent
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10A
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ated
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ral
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lant
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ary
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ced
ures
20
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liers
-
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ay
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s26
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liers
-
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ay
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liers
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liers
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ens
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ton
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n Tr
ent
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derd
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and
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ders
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ale
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al H
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50%
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nive
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pita
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datio
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nbro
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s H
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and
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916
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1
Cen
tral M
anch
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r Uni
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Hos
pita
ls N
HS
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datio
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90%
Man
ches
ter R
oyal
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mar
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612
88%
93%
2.5
43%
67.8
15%
99%
Traf
ford
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eral
Hos
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l33
79
86%
93%
2.1
41%
69.2
47%
51%
Che
lsea
and
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tmin
ster
Hos
pita
l N
HS
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datio
n Tr
ust
87%
Che
lsea
& W
estm
inst
er H
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tal
374
1147
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%2.
141
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.10%
70%
Che
ster
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Roy
al H
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tal N
HS
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datio
n Tr
ust
103%
Che
ster
field
Roy
al H
ospi
tal
762
1095
%95
%2.
243
%68
.936
%27
%
City
Hos
pita
ls S
unde
rland
NH
S Fo
unda
tion
Trus
t84
%
Sund
erla
nd R
oyal
Hos
pita
l84
411
86%
98%
2.2
44%
67.6
0%98
%
Col
ches
ter H
ospi
tal U
nive
rsity
NH
S Fo
unda
tion
Trus
t97
%
Col
ches
ter G
ener
al H
ospi
tal
1,11
710
100%
100%
2.2
39%
70.9
26%
89%
Cou
ntes
s of
Che
ster
Hos
pita
l NH
S Fo
unda
tion
Trus
t80
%
Cou
ntes
s of
Che
ster
Hos
pita
l28
48
97%
98%
2.2
40%
71.3
0%10
0%
209www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
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2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
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lant
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rim
ary
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ced
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20
12
Out
liers
-
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ay
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rtal
ity
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Mo
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-
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e27
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liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
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prim
ary
oper
atio
ns p
erfo
rmed
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3 on
war
ds. U
nits
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side
99.
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ontr
ol li
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(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
prim
ary
oper
atio
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erfo
rmed
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war
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nits
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99.
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(app
rox
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are
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in li
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ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Cou
nty
Durh
am a
nd D
arlin
gton
NH
S Fo
unda
tion
Trus
t87
%
Bish
op A
uckla
nd H
ospi
tal
408
1997
%99
%1.
948
%67
.311
%90
%
Dar
lingt
on M
emor
ial H
ospi
tal
256
1398
%98
%2.
439
%69
.023
%75
%
Uni
vers
ity H
ospi
tal o
f Nor
th D
urha
m53
612
96%
97%
2.2
44%
70.3
11%
97%
Cro
ydon
Hea
lth S
ervi
ces
NH
S Tr
ust
67%
Cro
ydon
Uni
vers
ity H
ospi
tal
224
77%
91%
2.4
25%
68.1
8%92
%
Cw
m T
af L
ocal
Hea
lth B
oard
118%
Prin
ce C
harle
s H
ospi
tal
341
710
0%10
0%2.
245
%67
.621
%95
%1
The
Roy
al G
lam
orga
n H
ospi
tal
583
1110
0%99
%2.
045
%68
.32%
80%
Dar
tford
and
Gra
vesh
am N
HS
Trus
t84
%
Dar
ent V
alle
y H
ospi
tal
575
610
0%99
%2.
040
%70
.971
%70
%
Der
by H
ospi
tals
NH
S Fo
unda
tion
Trus
t86
%
Roy
al D
erby
Hos
pita
l1,
673
1696
%97
%2.
140
%69
.36%
100%
Don
cast
er a
nd B
asse
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Hos
pita
ls
NH
S Fo
unda
tion
Trus
t54
%
Bas
setla
w H
ospi
tal
173
797
%10
0%2.
143
%70
.213
%84
%
Don
cast
er R
oyal
Infir
mar
y44
115
98%
98%
2.1
43%
66.8
21%
52%
Dor
set C
ount
y H
ospi
tal N
HS
Foun
datio
n Tr
ust
99%
Dor
set C
ount
y H
ospi
tal
821
982
%98
%2.
242
%71
.00%
97%
Ealin
g H
ospi
tal N
HS
Trus
t79
%
Ealin
g H
ospi
tal
180
487
%99
%2.
140
%68
.628
%49
%
East
and
Nor
th H
ertfo
rdsh
ire N
HS
Trus
t84
%
List
er H
ospi
tal
22
100%
100%
3.0
0%57
.90%
0%
Que
en E
lizab
eth
II H
ospi
tal
227
1272
%98
%2.
338
%72
.923
%86
%
210 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
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abili
ty
(%) 2
01225
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rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
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ated
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emo
ral
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rim
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20
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-
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rtal
ity
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-
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East
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S Tr
ust
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Mac
cles
field
Dis
trict
Gen
eral
H
ospi
tal
318
397
%99
%2.
143
%71
.11%
99%
East
Ken
t Hos
pita
ls U
nive
rsity
NH
S Fo
unda
tion
Trus
t10
1%
Que
en E
lizab
eth
The
Que
en M
othe
r H
ospi
tal
865
1193
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039
%69
.62%
96%
2
Willi
am H
arve
y H
ospi
tal (
Ashf
ord)
1,07
014
83%
98%
2.1
40%
69.9
0%76
%
East
Lan
cash
ire H
ospi
tals
NH
S Tr
ust
85%
Bur
nley
Gen
eral
Hos
pita
l70
618
73%
74%
2.1
40%
69.7
15%
65%
Roy
al B
lack
burn
Infir
mar
y70
1554
%96
%2.
633
%74
.613
%41
%
East
Sus
sex
Hos
pita
ls N
HS
Trus
t70
%
Con
ques
t Hos
pita
l48
19
99%
99%
2.1
43%
68.9
0%99
%2
East
bour
ne D
istri
ct G
ener
al H
ospi
tal
420
964
%90
%2.
435
%72
.60%
99%
Epso
m a
nd S
t Hel
ier U
nive
rsity
H
ospi
tals
NH
S Tr
ust
95%
The
Elec
tive
Orth
opae
dic
Cen
tre2,
710
2598
%98
%2.
038
%70
.41%
65%
Frim
ley
Park
Hos
pita
l NH
S Fo
unda
tion
Trus
t96
%
Frim
ley
Park
Hos
pita
l1,
211
1996
%99
%2.
042
%69
.50%
92%
Gat
eshe
ad H
ealth
NH
S Fo
unda
tion
Trus
t11
1%
The
Nor
th E
ast N
HS
Surg
ery
Cen
tre92
718
92%
98%
2.3
44%
68.6
8%91
%
Geo
rge
Elio
t Hos
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l NH
S Tr
ust
94%
Geo
rge
Elio
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l - A
cute
Se
rvic
es45
57
90%
98%
2.1
41%
69.2
4%87
%
Glo
uces
ters
hire
Hos
pita
ls N
HS
Foun
datio
n Tr
ust
62%
Che
ltenh
am G
ener
al H
ospi
tal
766
1210
0%10
0%2.
139
%71
.438
%10
0%
Glo
uces
ters
hire
Roy
al H
ospi
tal
298
1396
%96
%2.
044
%69
.134
%88
%
211www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
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-
90 D
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Mo
rtal
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Hip
R
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e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Gre
at W
este
rn H
ospi
tals
NH
S Fo
unda
tion
Trus
t93
%
The
Gre
at W
este
rn H
ospi
tal
1,11
314
89%
97%
2.1
41%
69.1
0%99
%
Guy
's a
nd S
t Tho
mas
' NH
S Fo
unda
tion
Trus
t89
%
Guy
's H
ospi
tal
783
1438
%96
%2.
042
%63
.40%
92%
Guy
's N
uffie
ld H
ouse
42
50%
100%
2.0
50%
66.9
0%0%
St T
hom
as' H
ospi
tal
224
27%
64%
2.0
21%
70.1
0%10
0%
Ham
pshi
re H
ospi
tals
NH
S Fo
unda
tion
Trus
t91
%
Bas
ings
toke
and
Nor
th H
amps
hire
H
ospi
tal
947
1194
%10
0%2.
039
%70
.16%
88%
2
Roy
al H
amps
hire
Cou
nty
Hos
pita
l64
97
96%
98%
2.2
41%
70.3
0%29
%
Har
roga
te a
nd D
istri
ct N
HS
Foun
datio
n Tr
ust
87%
Har
roga
te D
istri
ct H
ospi
tal
765
994
%97
%2.
045
%70
.20%
92%
Hea
rt of
Eng
land
NH
S Fo
unda
tion
Trus
t70
%
Goo
d H
ope
Hos
pita
l32
313
54%
93%
2.1
43%
70.5
1%95
%
Solih
ull H
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785
2360
%95
%2.
141
%68
.866
%89
%
Hea
ther
woo
d an
d W
exha
m P
ark
Hos
pita
ls N
HS
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datio
n Tr
ust
98%
Hea
ther
woo
d H
ospi
tal
636
1196
%98
%2.
039
%69
.46%
100%
Wex
ham
Par
k H
ospi
tal
201
1194
%99
%2.
441
%71
.61%
97%
Hin
chin
gbro
oke
Hea
lth C
are
NH
S Tr
ust
89%
Hin
chin
gbro
oke
Hos
pita
l62
47
97%
93%
2.2
42%
69.5
0%10
0%
212 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
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abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
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2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
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Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
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emo
ral
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lant
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P
rim
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20
12
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ay
Mo
rtal
ity
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s26
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Hom
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n U
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pita
l NH
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unda
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Trus
t96
%
Hom
erto
n U
nive
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Hos
pita
l17
65
73%
88%
2.2
29%
67.5
14%
89%
1
Hul
l and
Eas
t Yor
kshi
re H
ospi
tals
N
HS
Trus
t75
%
Cas
tle H
ill H
ospi
tal
741
1984
%94
%2.
141
%67
.910
%91
%
Hyw
el D
da L
ocal
Hea
lth B
oard
94%
Bron
glai
s G
ener
al H
ospi
tal
176
410
0%10
0%2.
538
%72
.234
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%
Prin
ce P
hilip
Hos
pita
l60
69
100%
100%
1.8
42%
69.7
0%10
0%
Wes
t Wal
es G
ener
al H
ospi
tal
466
98%
100%
2.0
48%
70.2
50%
95%
With
ybus
h G
ener
al H
ospi
tal
432
510
0%10
0%2.
144
%68
.60%
100%
2
Impe
rial C
olle
ge H
ealth
care
NH
S Tr
ust
87%
Cha
ring
Cro
ss H
ospi
tal
629
1693
%97
%2.
137
%67
.838
%85
%
Ipsw
ich
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pita
l NH
S Tr
ust
90%
Ipsw
ich
Hos
pita
l79
810
96%
99%
2.2
40%
70.9
36%
100%
Isle
of W
ight
NH
S PC
T45
2%
St M
ary'
s H
ospi
tal
535
599
%99
%2.
139
%70
.277
%10
0%
Jam
es P
aget
Uni
vers
ity H
ospi
tals
N
HS
Foun
datio
n Tr
ust
94%
Jam
es P
aget
Uni
vers
ity H
ospi
tal
628
798
%99
%2.
338
%71
.627
%18
%2
Ket
terin
g G
ener
al H
ospi
tal N
HS
Foun
datio
n Tr
ust
98%
Ket
terin
g G
ener
al H
ospi
tal
760
878
%98
%2.
043
%68
.821
%99
%
Kin
g's
Col
lege
Hos
pita
l NH
S Fo
unda
tion
Trus
t77
%
Kin
g's
Col
lege
Hos
pita
l (D
enm
ark
Hill)
372
1099
%10
0%2.
135
%66
.71%
93%
Kin
gsto
n H
ospi
tal N
HS
Trus
t17
%
Kin
gsto
n H
ospi
tal
137
77%
92%
2.3
17%
68.5
0%71
%
213www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Lanc
ashi
re T
each
ing
Hos
pita
ls N
HS
Foun
datio
n Tr
ust
94%
Cho
rley
and
Sout
h R
ibbl
e H
ospi
tal
760
1298
%10
0%2.
240
%68
.339
%73
%
Leed
s Te
achi
ng H
ospi
tals
NH
S Tr
ust
88%
Cha
pel A
llerto
n H
ospi
tal
1,13
320
89%
99%
2.1
42%
68.9
0%99
%
Lew
isha
m H
ealth
care
NH
S Tr
ust
90%
Riv
ersi
de T
reat
men
t Cen
tre26
96
88%
96%
2.2
36%
67.8
16%
93%
Luto
n an
d D
unst
able
Hos
pita
l NH
S Fo
unda
tion
Trus
t88
%
Luto
n &
Dun
stab
le H
ospi
tal
628
1298
%99
%2.
239
%70
.67%
37%
Mai
dsto
ne a
nd T
unbr
idge
Wel
ls N
HS
Trus
t99
%
The
Tunb
ridge
Wel
ls H
ospi
tal
1,02
913
99%
100%
2.0
42%
70.3
17%
84%
Med
way
NH
S Fo
unda
tion
Trus
t89
%
Med
way
Mar
itim
e H
ospi
tal
687
987
%99
%2.
241
%68
.20%
85%
2
Mid
Che
shire
Hos
pita
ls N
HS
Foun
datio
n Tr
ust
54%
Leig
hton
Hos
pita
l29
99
97%
98%
2.2
44%
70.6
18%
96%
Mid
Ess
ex H
ospi
tal S
ervi
ces
NH
S Tr
ust
86%
Bro
omfie
ld H
ospi
tal
833
1295
%98
%2.
143
%70
.711
%10
0%
Mid
Sta
fford
shire
NH
S Fo
unda
tion
Trus
t10
5%
Can
nock
Cha
se H
ospi
tal
591
1196
%98
%2.
142
%68
.416
%76
%
Staf
ford
Hos
pita
l47
662
%96
%2.
840
%75
.64%
83%
Mid
Yor
kshi
re H
ospi
tals
NH
S Tr
ust
83%
Dew
sbur
y an
d D
istri
ct H
ospi
tal
354
898
%99
%2.
145
%68
.088
%97
%
Pind
erfie
lds
Gen
eral
Hos
pita
l64
212
85%
89%
2.2
45%
67.5
6%99
%
214 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
Milt
on K
eyne
s H
ospi
tal N
HS
Foun
datio
n Tr
ust
86%
Milt
on K
eyne
s H
ospi
tal
389
798
%98
%2.
141
%69
.20%
60%
New
ham
Uni
vers
ity H
ospi
tal N
HS
Trus
t87
%
Gat
eway
Sur
gica
l Cen
tre18
610
0%10
0%2.
444
%67
.314
%10
0%
New
ham
Gen
eral
Hos
pita
l10
310
0%10
0%2.
340
%70
.90%
100%
Nor
folk
and
Nor
wic
h U
nive
rsity
H
ospi
tals
NH
S Fo
unda
tion
Trus
t99
%
Nor
folk
& N
orw
ich
Hos
pita
l1,
369
2099
%10
0%2.
243
%72
.23%
91%
Nor
tham
pton
Gen
eral
Hos
pita
l NH
S Tr
ust
107%
Nor
tham
pton
Gen
eral
Hos
pita
l (A
cute
)61
312
85%
97%
2.2
36%
69.9
0%67
%
Nor
th B
risto
l NH
S Tr
ust
94%
Fren
chay
Hos
pita
l72
1269
%93
%2.
443
%73
.464
%96
%
Sout
hmea
d H
ospi
tal
1,67
129
88%
95%
2.2
43%
68.1
26%
75%
2
Nor
th C
umbr
ia U
nive
rsity
Hos
pita
ls
NH
S Tr
ust
88%
Cum
berla
nd In
firm
ary
401
1193
%97
%2.
244
%70
.750
%10
0%
Wes
t Cum
berla
nd H
ospi
tal
296
769
%98
%2.
545
%69
.567
%98
%
Nor
ther
n D
evon
Hea
lthca
re N
HS
Trus
t10
0%
Nor
th D
evon
Dis
trict
Hos
pita
l68
710
91%
98%
2.1
42%
70.0
1%88
%
Nor
ther
n Li
ncol
nshi
re a
nd G
oole
H
ospi
tals
NH
S Fo
unda
tion
Trus
t77
%
Dia
na P
rince
ss o
f Wal
es H
ospi
tal
387
698
%10
0%2.
145
%69
.154
%88
%
Goo
le T
reat
men
t Cen
tre32
24
97%
98%
1.9
46%
69.1
54%
97%
Scun
thor
pe G
ener
al H
ospi
tal
179
598
%99
%2.
047
%68
.124
%58
%
215www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Nor
th M
iddl
esex
Uni
vers
ity H
ospi
tal
NH
S Tr
ust
75%
Nor
th M
iddl
esex
Hos
pita
l22
16
100%
100%
2.3
27%
68.6
0%99
%
Nor
th T
ees
and
Har
tlepo
ol N
HS
Foun
datio
n Tr
ust
93%
Uni
vers
ity H
ospi
tal o
f Har
tlepo
ol84
48
92%
100%
2.1
44%
67.5
19%
80%
2
Uni
vers
ity H
ospi
tal o
f Nor
th T
ees
94
78%
89%
2.1
38%
75.4
0%10
0%2
Nor
thum
bria
Hea
lthca
re N
HS
Foun
datio
n Tr
ust
94%
Hex
ham
Gen
eral
Hos
pita
l55
613
98%
99%
1.8
41%
68.5
41%
100%
Nor
th T
ynes
ide
Gen
eral
Hos
pita
l74
115
100%
99%
2.1
44%
69.4
16%
100%
2
Wan
sbec
k H
ospi
tal
785
1310
0%99
%2.
145
%69
.229
%10
0%
Nor
th W
est L
ondo
n H
ospi
tals
NH
S Tr
ust
77%
Cen
tral M
iddl
esex
Hos
pita
l35
715
89%
96%
2.0
38%
69.0
0%81
%
Nor
thw
ick
Park
Hos
pita
l10
16
72%
96%
2.2
48%
73.1
0%56
%
Not
tingh
am U
nive
rsity
Hos
pita
ls
NH
S Tr
ust
102%
Not
tingh
am C
ity H
ospi
tal
1,17
217
98%
100%
2.2
45%
69.2
7%64
%
Que
ens
Med
ical
Cen
tre N
ottin
gham
U
nive
rsity
Hos
pita
l31
314
99%
100%
2.1
41%
69.4
9%77
%
Oxf
ord
Uni
vers
ity H
ospi
tals
NH
S Tr
ust
99%
John
Rad
cliff
e H
ospi
tal
252
100%
100%
1.9
24%
74.4
0%10
0%
Nuf
field
Orth
opae
dic
Cen
tre1,
791
1894
%96
%2.
143
%68
.60%
82%
Penn
ine
Acut
e H
ospi
tals
NH
S Tr
ust
73%
Fairf
ield
Gen
eral
Hos
pita
l61
617
77%
97%
2.2
39%
69.5
19%
66%
Nor
th M
anch
este
r Gen
eral
Hos
pita
l36
610
84%
91%
2.2
42%
68.4
16%
26%
216 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
Roy
al O
ldha
m H
ospi
tal
202
1264
%95
%2.
238
%69
.338
%6%
Pete
rbor
ough
and
Sta
mfo
rd
Hos
pita
ls N
HS
Foun
datio
n Tr
ust
87%
Pete
rbor
ough
City
Hos
pita
l81
616
86%
96%
2.2
40%
69.8
68%
70%
Plym
outh
Hos
pita
ls N
HS
Trus
t92
%
Derri
ford
Hos
pita
l86
015
97%
99%
2.2
44%
68.1
1%54
%
Pool
e H
ospi
tal N
HS
Foun
datio
n Tr
ust
47%
Pool
e H
ospi
tal
106
1083
%87
%2.
534
%74
.90%
82%
Ports
mou
th H
ospi
tals
NH
S Tr
ust
84%
Que
en A
lexa
ndra
Hos
pita
l1,
162
2210
0%99
%2.
040
%69
.315
%99
%
Rob
ert J
ones
and
Agn
es H
unt
Orth
opae
dic
And
Dis
trict
Hos
pita
l N
HS
Trus
t10
1%
Rob
ert J
ones
& A
gnes
Hun
t O
rthop
aedi
c H
ospi
tal
2,94
435
98%
99%
2.0
43%
68.8
24%
92%
Roy
al B
erks
hire
NH
S Fo
unda
tion
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Roy
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Roy
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n H
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HS
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n Tr
ust
96%
Roy
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n H
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424
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443
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Roy
al C
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all H
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89%
Roy
al C
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all H
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)56
519
84%
94%
2.2
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70.4
13%
56%
St M
icha
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Hos
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l39
017
84%
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1.8
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14%
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Roy
al D
evon
and
Exe
ter N
HS
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datio
n Tr
ust
93%
Roy
al D
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& E
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r Hos
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l (W
onfo
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1,44
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92%
97%
2.1
43%
70.5
0%99
%
Roy
al F
ree
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on N
HS
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datio
n Tr
ust
76%
The
Roy
al F
ree
Hos
pita
l28
18
77%
100%
2.2
34%
71.1
79%
99%
217www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
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rd/C
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Com
plia
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S T
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al
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nly)
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Ho
spita
l
No
. of
Pro
ced
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20
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. of
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tant
s 20
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nsen
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Op
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2012
Per
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23 C
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HS
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Onl
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the
per
cent
age
of c
ases
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mitt
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o th
e N
JR c
omp
ared
to
HE
S/P
ED
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24 C
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nt R
ate
- p
erce
ntag
e of
cas
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itted
to
the
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with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
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s w
hich
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a va
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NH
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99.9
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s (a
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ark
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© N
atio
nal J
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Reg
istr
y 20
13
Roy
al L
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pool
and
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Uni
vers
ity H
ospi
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S Tr
ust
87%
Bro
adgr
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Hos
pita
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817
64%
80%
2.1
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67.2
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%
The
Roy
al L
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ity
Hos
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641
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.10%
73%
Roy
al N
atio
nal O
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c H
ospi
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S Tr
ust
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The
Roy
al N
atio
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189
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%
Roy
al S
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ount
y H
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HS
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datio
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ust
89%
Roy
al S
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670
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17%
Roy
al U
nite
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ath
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ust
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Roy
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687
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239
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Salfo
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t70
%
Salfo
rd R
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340
1236
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t96
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l68
010
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%
Sand
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t91
%
City
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%
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lth C
are
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ust
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boro
ugh
Gen
eral
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88
84%
100%
2.1
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69.8
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%
Shef
field
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chin
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tals
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t69
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Nor
ther
n G
ener
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243
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%
Roy
al H
alla
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ire H
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824
1197
%98
%2.
344
%69
.472
%96
%
218 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
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S T
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nly)
23
Ho
spita
l
No
. of
Pro
ced
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20
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. of
Co
nsul
tant
s 20
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Co
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Op
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2012
Per
cent
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ated
A
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al H
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ity H
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t62
%
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218
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%
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245
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%
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h Ty
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de N
HS
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datio
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ust
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tal
290
610
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239
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219www.njrcentre.org.uk
Trus
t/Lo
cal H
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rd/C
ompa
ny
Com
plia
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S T
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lth B
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nly)
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Ho
spita
l
No
. of
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ced
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20
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. of
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Op
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2012
Per
cent
age
of
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ated
A
ceta
bul
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20
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Per
cent
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of
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ated
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ral
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lant
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20
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23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
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dur
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ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
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prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
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atio
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200
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war
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nits
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rox
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ged
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ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Sout
h W
arw
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hire
NH
S Fo
unda
tion
Trus
t89
%
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k H
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lthca
re N
HS
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t85
%
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pita
l (To
otin
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%
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now
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1
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t92
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Step
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215
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datio
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sells
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l Hos
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HS
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datio
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ust
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Hilli
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182
1371
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Mou
nt V
erno
n Tr
eatm
ent C
entre
512
1192
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041
%69
.70%
84%
220 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
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S T
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/Loc
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Hea
lth B
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O
nly)
23
Ho
spita
l
No
. of
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ced
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20
12
No
. of
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12
Co
nsen
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rag
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SA
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de
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rag
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ge
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Op
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Per
cent
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ated
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P
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Roy
al V
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ria In
firm
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67%
100%
The
Prin
cess
Ale
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ra H
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NH
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ust
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Prin
cess
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701
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Que
en E
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t81
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Que
en E
lizab
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pita
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911
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98%
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71.1
59%
99%
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Rot
herh
am N
HS
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datio
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ust
93%
Rot
herh
am D
istri
ct G
ener
al H
ospi
tal
701
1298
%98
%2.
044
%68
.36%
64%
2
The
Roy
al B
ourn
emou
th a
nd
Chr
istc
hurc
h H
ospi
tals
NH
S Fo
unda
tion
Trus
t97
%
Roy
al B
ourn
emou
th H
ospi
tal
2,14
215
97%
97%
2.1
39%
71.1
2%10
0%
The
Roy
al O
rthop
aedi
c H
ospi
tal
NH
S Fo
unda
tion
Trus
t73
%
Roy
al O
rthop
aedi
c H
ospi
tal
1,36
020
87%
97%
2.0
40%
65.8
16%
63%
The
Roy
al W
olve
rham
pton
Hos
pita
ls
NH
S Tr
ust
71%
New
Cro
ss H
ospi
tal
859
1399
%97
%2.
243
%69
.12%
83%
The
Whi
tting
ton
Hos
pita
l NH
S Tr
ust
73%
The
Whi
tting
ton
Hos
pita
l22
67
85%
99%
2.1
34%
68.5
5%28
%
Uni
ted
Linc
olns
hire
Hos
pita
ls N
HS
Trus
t74
%
Cou
nty
Hos
pita
l Lou
th14
15
99%
99%
2.0
46%
70.1
30%
99%
Gra
ntha
m a
nd D
istri
ct H
ospi
tal
272
797
%10
0%2.
131
%69
.51%
56%
Linc
oln
Cou
nty
Hos
pita
l26
712
84%
98%
2.2
39%
71.2
50%
100%
Pilg
rim H
ospi
tal
461
1297
%97
%2.
241
%70
.720
%50
%
221www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
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ated
F
emo
ral
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lant
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rim
ary
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ced
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20
12
Out
liers
-
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ay
Mo
rtal
ity
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s26
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liers
-
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ay
Mo
rtal
ity
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liers
-
Hip
R
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ion
Rat
e27
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liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
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ary
oper
atio
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erfo
rmed
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nits
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99.
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rox
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ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Uni
vers
ity C
olle
ge L
ondo
n H
ospi
tals
N
HS
Foun
datio
n Tr
ust
96%
Uni
vers
ity C
olle
ge H
ospi
tal
313
1057
%93
%2.
136
%64
.74%
29%
Uni
vers
ity H
ospi
tal B
irmin
gham
NH
S Tr
ust
80%
Que
en E
lizab
eth
Hos
pita
l B
irmin
gham
329
13%
78%
2.2
44%
73.9
0%10
0%
Uni
vers
ity H
ospi
tal o
f Nor
th
Staf
ford
shire
NH
S Tr
ust
80%
City
Gen
eral
Hos
pita
l64
112
100%
100%
2.2
44%
68.6
2%79
%
Uni
vers
ity H
ospi
tal o
f Sou
th
Man
ches
ter N
HS
Foun
datio
n Tr
ust
82%
Wyt
hens
haw
e H
ospi
tal
438
790
%98
%2.
139
%69
.92%
95%
Uni
vers
ity H
ospi
tals
Bris
tol N
HS
Foun
datio
n Tr
ust
61%
Bris
tol R
oyal
Hos
pita
l for
Chi
ldre
n2
150
%10
0%1.
50%
12.2
0%10
0%
Bris
tol R
oyal
Infir
mar
y33
1139
%88
%2.
631
%74
.268
%10
0%
Uni
vers
ity H
ospi
tals
Cov
entry
and
W
arw
icks
hire
NH
S Tr
ust
86%
Hos
pita
l of S
t Cro
ss92
922
97%
97%
1.9
39%
67.8
6%63
%1
Uni
vers
ity H
ospi
tal (
Cov
entry
)55
725
96%
96%
2.4
39%
70.6
7%84
%
Uni
vers
ity H
ospi
tals
of L
eice
ster
N
HS
Trus
t85
%
Gle
nfie
ld H
ospi
tal
11
100%
100%
2.0
0%67
.30%
0%
Leic
este
r Gen
eral
Hos
pita
l1,
798
2394
%99
%2.
140
%69
.611
%92
%
Uni
vers
ity H
ospi
tals
of M
orec
ambe
B
ay N
HS
Foun
datio
n Tr
ust
73%
Furn
ess
Gen
eral
Hos
pita
l38
67
98%
100%
2.0
45%
69.5
1%99
%
Roy
al L
anca
ster
Infir
mar
y16
411
99%
92%
2.3
42%
70.9
30%
97%
Wes
tmor
land
Gen
eral
Hos
pita
l36
913
84%
99%
1.9
41%
68.0
1%93
%
222 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
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abili
ty
(%) 2
01225
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rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
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ated
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emo
ral
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lant
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P
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ced
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20
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Wal
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HS
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t92
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Man
or H
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tal
501
1110
0%10
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143
%69
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%
War
ringt
on a
nd H
alto
n H
ospi
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N
HS
Foun
datio
n Tr
ust
72%
War
ringt
on H
ospi
tal
525
796
%94
%2.
244
%68
.65%
48%
Wes
tern
Sus
sex
Hos
pita
ls N
HS
Trus
t82
%
St R
icha
rd's
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pita
l1,
252
1774
%99
%2.
239
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%64
%1
Wes
t Her
tford
shire
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pita
ls N
HS
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t97
%
St A
lban
s C
ity H
ospi
tal
780
1288
%95
%2.
042
%69
.20%
99%
22
Wat
ford
Gen
eral
Hos
pita
l17
79
82%
88%
2.7
35%
74.4
2%96
%1
Wes
t Mid
dles
ex U
nive
rsity
Hos
pita
l N
HS
Trus
t69
%
Wes
t Mid
dles
ex U
nive
rsity
Hos
pita
l19
07
64%
94%
2.1
41%
69.1
52%
98%
Wes
ton
Area
Hea
lth N
HS
Trus
t78
%
Wes
ton
Gen
eral
294
991
%98
%2.
144
%70
.60%
76%
Wes
t Suf
folk
Hos
pita
ls N
HS
Trus
t10
0%
Wes
t Suf
folk
Hos
pita
l77
711
100%
100%
2.1
42%
71.0
64%
95%
Whi
pps
Cro
ss U
nive
rsity
Hos
pita
l N
HS
Trus
t13
2%
Whi
pps
Cro
ss U
nive
rsity
Hos
pita
l14
99
72%
61%
2.1
31%
70.3
13%
56%
Wirr
al U
nive
rsity
Tea
chin
g H
ospi
tal
NH
S Fo
unda
tion
Trus
t92
%
Arro
we
Park
Hos
pita
l44
512
85%
99%
2.5
41%
72.2
0%99
%
Cla
tterb
ridge
Hos
pita
l62
915
86%
99%
1.9
41%
67.3
0%10
0%
Wor
cest
ersh
ire A
cute
Hos
pita
ls N
HS
Trus
t81
%
Alex
andr
a H
ospi
tal
572
794
%10
0%2.
142
%69
.657
%62
%
Kid
derm
inst
er T
reat
men
t Cen
tre89
575
%98
%1.
751
%67
.748
%85
%
Wor
cest
ersh
ire R
oyal
Hos
pita
l36
36
87%
98%
2.1
39%
69.8
13%
94%
223www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
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01224
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abili
ty
(%) 2
01225
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rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
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ay
Mo
rtal
ity
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s26
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liers
-
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ay
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rtal
ity
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liers
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Hip
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liers
-
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e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13
Wrig
htin
gton
Wig
an a
nd L
eigh
NH
S Fo
unda
tion
Trus
t96
%
Wrig
htin
gton
Hos
pita
l2,
266
2510
0%10
0%2.
145
%66
.41%
86%
Wye
Val
ley
NH
S Tr
ust
81%
Her
efor
d C
ount
y H
ospi
tal
695
1110
0%10
0%2.
041
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.40%
82%
Yeov
il D
istri
ct H
ospi
tal N
HS
Foun
datio
n Tr
ust
99%
Yeov
il D
istri
ct H
ospi
tal
676
798
%99
%2.
140
%71
.61%
77%
York
Tea
chin
g H
ospi
tal N
HS
Foun
datio
n Tr
ust
97%
York
Hos
pita
l35
36
89%
99%
2.3
39%
70.0
1%82
%1
Aspe
n H
ealth
care
Lim
ited
Cla
rem
ont H
ospi
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596
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943
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%
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ly H
ouse
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pita
l33
591
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943
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Park
side
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pita
l20
912
96%
73%
1.8
45%
66.4
0%88
%
Ben
ende
n H
ealth
care
Soc
iety
Ben
ende
n H
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tal
271
1195
%99
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046
%70
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BM
I Hea
lthca
re
BM
I Ale
xand
ra H
ospi
tal C
head
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130
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41%
67.3
9%96
%
BM
I Bat
h C
linic
242
896
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937
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.714
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%
BM
I Bea
rdw
ood
Priv
ate
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l10
210
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52%
69.5
12%
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BM
I Bis
hops
Woo
d H
ospi
tal
124
898
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%69
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BM
I Bla
ckhe
ath
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pita
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837
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I Bur
y St
Edm
unds
317
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044
%69
.296
%98
%
BM
I Cha
ucer
Hos
pita
l15
38
99%
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2.0
44%
70.8
0%75
%
BM
I Che
lsfie
ld P
ark
Hos
pita
l27
78
100%
90%
2.0
47%
70.3
4%54
%
224 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
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abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
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emo
ral
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lant
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P
rim
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Pro
ced
ures
20
12
Out
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ay
Mo
rtal
ity
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s26
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rtal
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e27
BM
I Cle
men
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Chu
rchi
ll H
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225www.njrcentre.org.uk
Trus
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24 C
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© N
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226 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
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227www.njrcentre.org.uk
Trus
t/Lo
cal H
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Boa
rd/C
ompa
ny
Com
plia
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JR c
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HE
S/P
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kab
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© N
atio
nal J
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Reg
istr
y 20
13
Nuf
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68.0
2%24
%
Nuf
field
Hea
lth S
hrew
sbur
y H
ospi
tal
145
810
0%94
%1.
848
%67
.50%
96%
Nuf
field
Hea
lth T
aunt
on H
ospi
tal
374
893
%99
%1.
942
%69
.80%
78%
Nuf
field
Hea
lth T
ees
Hos
pita
l51
111
100%
99%
1.9
44%
66.3
1%65
%2
Nuf
field
Hea
lth T
he G
rosv
enor
H
ospi
tal
365
910
0%99
%1.
944
%69
.437
%10
0%
Nuf
field
Hea
lth T
he M
anor
Hos
pita
l46
013
89%
88%
1.8
48%
67.9
0%85
%
Nuf
field
Hea
lth T
unbr
idge
Wel
ls
Hos
pita
l12
83
95%
93%
1.9
49%
70.7
0%95
%
228 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
Nuf
field
Hea
lth W
arw
icks
hire
H
ospi
tal
287
1686
%90
%2.
043
%68
.00%
84%
Nuf
field
Hea
lth W
esse
x H
ospi
tal
160
1686
%89
%1.
845
%68
.12%
89%
Nuf
field
Hea
lth W
okin
g H
ospi
tal
747
99%
89%
1.8
39%
67.7
2%6%
Nuf
field
Hea
lth W
olve
rham
pton
H
ospi
tal
300
1099
%98
%1.
943
%70
.10%
83%
Nuf
field
Hea
lth Y
ork
Hos
pita
l33
57
97%
92%
1.9
48%
69.2
1%75
%2
Vale
Hos
pita
l23
59
98%
83%
1.9
37%
68.6
0%37
%
Orth
opae
dic
Spin
e an
d Sp
ecia
list
Hos
pita
lO
rthop
aedi
cs a
nd S
pine
Spe
cial
ist
Hos
pita
l38
110
0%10
0%2.
118
%71
.60%
0%
Ram
say
Hea
lth C
are
Asht
ead
Hos
pita
l35
97
96%
95%
1.9
37%
69.5
1%79
%2
Clift
on P
ark
Hos
pita
l84
99
97%
98%
1.8
46%
67.8
0%72
%2
Duc
hy H
ospi
tal
912
1297
%97
%1.
942
%67
.310
%27
%
Euxt
on H
all H
ospi
tal
222
1310
0%99
%1.
940
%66
.09%
76%
Fitz
willi
am H
ospi
tal
526
1399
%98
%1.
945
%67
.670
%80
%
Fulw
ood
Hal
l Hos
pita
l40
27
99%
100%
2.1
46%
67.7
3%75
%
Hor
ton
NH
S Tr
eatm
ent C
entre
809
1097
%98
%1.
941
%68
.20%
99%
2
Ken
dal N
HS
Trea
tmen
t Cen
tre76
596
%96
%1.
945
%67
.50%
89%
Mou
nt S
tuar
t Hos
pita
l34
510
99%
98%
2.0
42%
68.7
7%97
%
New
Hal
l Hos
pita
l31
08
100%
98%
1.9
45%
69.6
1%66
%1
2
Nor
th D
owns
Hos
pita
l29
48
98%
99%
1.8
40%
68.2
10%
72%
Not
tingh
am W
oodt
horp
e H
ospi
tal
873
1793
%97
%1.
743
%68
.219
%98
%
Oak
land
s H
ospi
tal
184
510
0%10
0%1.
641
%64
.20%
100%
Oak
s H
ospi
tal
345
788
%95
%1.
939
%70
.428
%99
%
Park
Hill
Hos
pita
l41
99
97%
100%
1.9
40%
69.6
23%
83%
229www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
rs w
ith re
spec
t to
revi
sion
s (a
t any
tim
e) fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
© N
atio
nal J
oint
Reg
istr
y 20
13©
Nat
iona
l Joi
nt R
egis
try
2012
Pine
hill
Hos
pita
l29
111
100%
99%
1.9
45%
68.8
4%68
%
Ren
acre
s H
all H
ospi
tal
179
510
0%97
%1.
936
%67
.68%
100%
Riv
ers
Hos
pita
l20
55
92%
87%
1.9
52%
68.7
49%
96%
Row
ley
Hal
l Hos
pita
l15
56
99%
99%
2.1
40%
69.5
8%71
%
Sprin
gfie
ld H
ospi
tal
481
994
%95
%2.
046
%68
.911
%10
0%
The
Ber
kshi
re In
depe
nden
t Hos
pita
l20
210
95%
88%
1.8
42%
68.3
3%85
%
The
York
shire
Clin
ic64
714
92%
93%
1.9
44%
67.6
0%52
%
Wes
t Mid
land
s H
ospi
tal
182
897
%95
%1.
945
%69
.419
%54
%
Win
field
Hos
pita
l29
19
97%
98%
1.8
35%
69.6
21%
86%
Woo
dlan
d H
ospi
tal
376
892
%95
%1.
943
%67
.410
%98
%
Spi
re H
ealth
care
Dun
edin
Hos
pita
l12
27
94%
92%
1.7
32%
69.5
11%
95%
2
Ella
nd H
ospi
tal
290
1410
0%97
%2.
145
%68
.074
%10
0%
Fyld
e C
oast
Hos
pita
l36
612
90%
92%
1.5
43%
68.1
3%65
%
Hul
l and
Eas
t Rid
ing
Hos
pita
l57
118
100%
95%
2.0
40%
69.1
5%95
%
Met
hley
Par
k H
ospi
tal
350
910
0%96
%2.
047
%67
.80%
100%
Reg
ency
Hos
pita
l21
97
100%
94%
1.8
37%
69.9
0%10
0%
Spi
re A
lexa
ndra
Hos
pita
l18
410
99%
93%
2.0
42%
68.1
1%67
%1
2
Spi
re B
risto
l Hos
pita
l45
020
95%
92%
2.0
45%
66.1
14%
89%
Spi
re B
ushe
y H
ospi
tal
504
1610
0%90
%1.
938
%65
.712
%99
%
Spi
re C
ambr
idge
Lea
Hos
pita
l58
719
99%
98%
1.7
42%
66.7
34%
72%
Spi
re C
ardi
ff H
ospi
tal
306
1499
%90
%2.
047
%63
.30%
41%
2
Spi
re C
hesh
ire H
ospi
tal
515
1010
0%88
%2.
043
%67
.12%
51%
1
Spi
re C
lare
Par
k H
ospi
tal
271
898
%94
%1.
848
%66
.60%
86%
2
Spi
re G
atw
ick
Par
k H
ospi
tal
303
898
%94
%1.
838
%67
.816
%96
%
230 www.njrcentre.org.uk
www.njrcentre.org.uk
© N
atio
nal J
oint
Reg
istr
y 20
13
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
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liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
Spi
re H
arpe
nden
Hos
pita
l23
216
100%
93%
1.9
40%
68.4
6%76
%
Spi
re H
arts
woo
d H
ospi
tal
301
1510
0%95
%2.
045
%67
.19%
32%
Spi
re L
eeds
Hos
pita
l30
412
99%
89%
1.8
40%
68.6
7%99
%
Spi
re L
eice
ster
Hos
pita
l37
618
98%
96%
2.0
40%
68.4
10%
86%
Spi
re L
ittle
Ast
on H
ospi
tal
274
1810
0%98
%1.
941
%70
.338
%94
%
Spi
re L
iver
pool
Hos
pita
l20
17
74%
86%
2.0
51%
67.2
1%96
%
Spi
re M
anch
este
r H
ospi
tal
183
1885
%95
%2.
042
%66
.52%
98%
Spi
re M
urra
yfie
ld H
ospi
tal
271
1098
%95
%1.
942
%67
.628
%10
0%
Spi
re N
orw
ich
Hos
pita
l94
215
95%
95%
1.9
44%
69.9
7%81
%
Spi
re P
arkw
ay H
ospi
tal
439
1196
%98
%1.
743
%67
.870
%78
%
Spi
re P
orts
mou
th H
ospi
tal
527
1599
%96
%1.
739
%70
.628
%98
%
Spi
re R
odin
g H
ospi
tal
178
1590
%94
%2.
041
%68
.72%
61%
Spi
re S
outh
ampt
on H
ospi
tal
719
1298
%82
%1.
846
%66
.15%
55%
2
Spi
re S
outh
Ban
k H
ospi
tal
200
896
%93
%1.
946
%70
.321
%10
0%
Spi
re S
t Sav
iour
s H
ospi
tal
217
950
%92
%1.
947
%70
.00%
88%
Spi
re S
usse
x H
ospi
tal
343
799
%96
%2.
034
%67
.80%
100%
Spi
re T
ham
es V
alle
y11
110
100%
90%
1.9
43%
71.8
4%10
0%
Spi
re T
unbr
idge
Wel
ls H
ospi
tal
813
99%
88%
1.6
31%
69.9
0%27
%1
Spi
re W
ashi
ngto
n H
ospi
tal
309
1796
%93
%1.
951
%66
.17%
99%
Spi
re W
elle
sley
Hos
pita
l31
110
97%
94%
1.8
42%
68.0
25%
84%
Spi
re Y
ale
Hos
pita
l26
913
94%
89%
2.1
42%
68.0
9%58
%
St A
ntho
nys
St A
ntho
nys
224
895
%91
%2.
042
%69
.13%
50%
St J
osep
hs H
ospi
tal
St J
osep
hs H
ospi
tal
136
1199
%95
%2.
055
%69
.84%
66%
The
Lond
on C
linic
The
Lond
on C
linic
168
1090
%64
%1.
640
%60
.10%
44%
231www.njrcentre.org.uk
Trus
t/Lo
cal H
ealth
Boa
rd/C
ompa
ny
Com
plia
nce
(NH
S T
rust
/Loc
al
Hea
lth B
oard
O
nly)
23
Ho
spita
l
No
. of
Pro
ced
ures
20
12
No
. of
Co
nsul
tant
s 20
12
Co
nsen
t R
ate
(%) 2
01224
Link
abili
ty
(%) 2
01225
Ave
rag
e A
SA
Gra
de
2012
Per
cent
age
Mal
e P
atie
nts
2012
Ave
rag
e A
ge
At
Op
erat
ion
2012
Per
cent
age
of
10A
R
ated
A
ceta
bul
ar
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Per
cent
age
of
10A
R
ated
F
emo
ral
Imp
lant
Hip
P
rim
ary
Pro
ced
ures
20
12
Out
liers
-
90 D
ay
Mo
rtal
ity
Hip
s26
Out
liers
-
90 D
ay
Mo
rtal
ity
Kne
es26
Out
liers
-
Hip
R
evis
ion
Rat
e27
Out
liers
-
Kne
e R
evis
ion
Rat
e27
23 C
omp
lianc
e (N
HS
Tru
st/L
ocal
Hea
lth B
oard
Onl
y) -
the
per
cent
age
of c
ases
sub
mitt
ed t
o th
e N
JR c
omp
ared
to
HE
S/P
ED
W.
24 C
onse
nt R
ate
- p
erce
ntag
e of
cas
es s
ubm
itted
to
the
NJR
with
pat
ient
con
sent
con
firm
ed25
Lin
kab
ility
- t
he p
rop
ortio
n of
rec
ord
s w
hich
incl
ude
a va
lid p
atie
nt’s
NH
S n
umb
er c
omp
ared
with
the
num
ber
of p
roce
dur
es r
ecor
ded
on
the
NJR
.26
Out
liers
with
resp
ect t
o 90
-day
mor
talit
y fo
llow
ing
prim
ary
oper
atio
ns p
erfo
rmed
from
200
3 on
war
ds. U
nits
out
side
99.
8% c
ontr
ol li
mits
(app
rox
3 S
Ds)
are
flag
ged
in li
ght r
ed (1
); th
ose
outs
ide
99.9
9% c
ontr
ol li
mits
are
flag
ged
in d
ark
red
(2).
27 O
utlie
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Glossary
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
233www.njrcentre.org.uk
A
Acetabular component The portion of a total hip replacement prosthesis that is inserted into the acetabulum - the socket part of a ball and socket joint.
Acetabular cup See Acetabular component.
Acetabular prosthesis See Acetabular component.
Antibiotic-loaded bone cement See cement.
Arthrodesis A procedure where the bones of a natural joint are fused together (stiffened).
Arthroplasty A procedure where a natural joint is reconstructed with an artificial prosthesis.
ABHI Association of British Healthcare Industries - the UK trade association of medical device suppliers.
ASA American Society of Anaesthesiologists scoring system for grading the overall physical condition of the patient, as follows:P1 – fit and healthy; P2 – mild disease, not incapacitating; P3 – incapacitating systemic disease; P4 – life threatening disease; P5 – expected to die within 24 hrs without an operation.
B
Bearing type The two surfaces that articulate together in a joint replacement. Options includemetal-on-polyethylene, metal-on-metal, ceramic-on-polyethylene, ceramic-on-metal and ceramic-on-ceramic.
Bilateral operation Operation performed on both sides, e.g. left and right knee procedures, carried out during a single operation.
BMI Body mass index. A statistical tool used to estimate a healthy body weight based on an individual’s height. The BMI is calculated by dividing a person’s weight (kg) by the square of their height (m2).
BOA British Orthopaedic Association - the professional body representing orthopaedic surgeons.
Bone cement See cement.
Brand (of prosthesis) The brand of a prosthesis (or implant) is the manufacturer's product name, e.g. the Exeter V40 brand for hips, the PFC Sigma brand for knees, the Mobility brand for ankles, the Delta Xtend brand for shoulders and the Coonrad Morrey for elbows.
C
CQC Care Quality Commission. Regulators of care provided by the NHS, local authorities, private companies and voluntary organisations.
Case ascertainment Proportion of all relevant joint replacement procedures performed in England and Wales that are entered into the NJR.
Case mix Term used to describe variation in surgical practice, relating to factors such as indications for surgery, patient age and gender.
Cement The material used to fix cemented joint replacements to bone - polymethyl methacrylate (PMMA). Antibiotic can be added to bone cement to try and reduce the risk of infection.
Cemented Prostheses designed to be fixed into the bone using cement.
Cementless Prostheses designed to be fixed into the bone by bony ingrowth or ongrowth, without using cement.
Compliance The percentage of all total joint procedures that have been entered into the NJR within any given period compared with the expected number of procedures performed. The expected number of procedures can be the number of levies returned, or for the NHS Sector only, the number of procedures submitted to HES and PEDW.
Competing risks survival analysis An alternative to standard survival analysis methods (such as Kaplan-Meier estimation or the Cox proportional hazards model) when there are competing risks. A competing risk can prevent the event of interest from occurring (in this case, death is a competing risk to the risk of revision as patients who die will never experience revision). A competing-risks survival analysis adjusts the results accordingly.
Confidence interval (CI) A confidence interval (CI) gives an estimated range of values which is likely to include the unknown population parameter (e.g. a revision rate) being estimated from the given sample. If independent samples are taken repeatedly from the same population, and a confidence interval calculated for each sample, then a certain percentage (confidence level: e.g. 95%) of the intervals will include the unknown population parameter.
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Confounding Systematic variation due to the presence of factors not on the causal pathway, which affect the outcome, which are unequally distributed amongst interventions being compared which leads to inaccurate inferences about the results.
Cox proportional hazards model A semi-parametric survival analysis model commonly used to model time-to-event data as it does not require the underlying hazard function to take a particular shape. As it is a multi-variable model, it can be used to explore the effects of covariates on the outcome of interest and reduce the impact of confounding.
Cross-linked polyethylene See modified polyethylene.
Cumulative hazard An ‘accumulated’ hazard rate over time; the hazard rate at a particular point in time is the rate of occurrence of the event (revision or death) amongst those in whom the event has not yet occurred. Estimated using the Nelson-Aalen estimate.
Cup See Acetabular component.
D
Data collection periods for annual report analysis
The NJR Annual Report Part One reports on data collected between 1 April 2012 and 31 March 2013 – the 2012/13 financial year. The NJR Annual Report Parts Two and Four analyse data on hip, knee, ankle, elbow, and shoulder procedures undertaken between 1 January and 31 December 2012 inclusive – the 2012 calendar year. The NJR Annual Report Part Three reports on hip, knee and ankle joint replacement revision rates for procedures that took place between 1 April 2003 and 31 December 2012.
DDH Developmental dysplasia of the hip. A condition where the hip joint is malformed, usually with a shallow socket (acetabulum), which may cause instability.
DH Department of Health.
DVT Deep vein thrombosis. A blood clot that can form in the veins of the leg, and is recognised as a significant risk after joint replacement surgery.
E
Excision arthroplasty A procedure where the articular ends of the bones are simply excised, so that a gap is created between them, or when a joint replacement is removed and not replaced by another prosthesis.
F
Femoral component (hip) Part of a total hip joint that is inserted into the femur (thigh bone) of the patient. It normally consists of a stem and head (ball).
Femoral component (knee) Portion of a knee prosthesis that is used to replace the articulating surface of the femur (thigh bone).
Femoral head Spherical portion of the femoral component of the artificial hip replacement.
Femoral prosthesis Portion of a total joint replacement used to replace damaged parts of the femur (thigh bone).
Femoral stem The part of a modular femoral component inserted into the femur (thigh bone). Has a femoral head mounted on it to form the complete femoral component.
Flexible parametric proportional hazards model
Developed by Royston and Parmar, this model extends the standard Cox proportional hazards approach by modelling the baseline distribution parametrically using a restricted cubic spline function. This allows more flexibility in modelling the shape of the baseline hazard function than using standard parametric distributions.
Funnel plot A graph of a performance measure for each unit plotted against the unit’s number of cases. Control limits are shown to indicate acceptable performance.
G
Glenoid component The portion of a total shoulder replacement prosthesis that is inserted into the scapula – the socket part of a ball and socket joint in conventional shoulder replacement or the ball part in reverse shoulder replacement.
Glenoid head Domed head portion of the glenoid component of the reverse shoulder replacement attached to the scapula.
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
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H
Head See Femoral head and/or Humeral head.
Healthcare provider NHS or independent sector organisation that provides healthcare; in the case of the NJR, orthopaedic hip, knee, ankle, elbow or shoulder replacement surgery.
HES Hospital Episode Statistics. Data on case mix, procedures, length of stay and other hospital statistics collected routinely by NHS hospitals in England.
HQIP Healthcare Quality Improvement Partnership. Manages the NJR on behalf of the Department of Health. Promotes quality in health and social care services and works to increase the impact that clinical audit has nationally.
Humeral component (elbow) Part of a total elbow joint that is inserted into the humerus (upper arm bone) of the patient to replace the articulating surface of the humerus.
Humeral component (shoulder) Part of a total or partial shoulder joint that is inserted into the humerus (upper arm bone) of the patient. It normally consists of a humeral stem and head (ball) in conventional shoulder replacement or a humeral stem and a humeral cup in a reverse shoulder replacement.
Humeral cup The shallow socket of a reverse shoulder replacement attached to the scapula.
Humeral head Domed head portion of the humeral component of the artificial shoulder replacement attached to the humeral stem.
Humeral prosthesis Portion of a total joint replacement used to replace damaged parts of the humerus (upper arm bone).
Humeral stem The part of a modular humeral component inserted into the humerus (upper arm bone). Has a humeral head or humeral cup mounted on it to form the complete humeral component.
Hybrid procedure Joint replacement procedure in which cement is used to fix one prosthetic component while the other is cementless. For hip procedures, the term hybrid covers both reverse hybrid (cementless stem, cemented socket) and hybrid (cemented stem, cementless socket).
I
Image/computer-guided surgery Surgery performed by the surgeon, using real-time images and data computed from these to assist alignment and positioning of prosthetic components.
Independent hospital A hospital managed by a commercial company that predominantly treats privately-funded patients but does also treat NHS-funded patients.
Index joint The primary joint replacement that is the subject of an NJR entry.
Indication (for surgery) The reason for surgery. The NJR system allows for more than one indication to be recorded.
ISTC Independent sector treatment centre (see Treatment centre).
K
Kaplan-Meier Estimates of the cumulative probability of failure (revision or death) that properly take into account ‘censored’ data. Censorings arise from incomplete follow up; for revision, for example, a patient may have died or reached the end the analysis period (end of 2012) without having been revised. The estimates do not adjust for any confounding factors.
L
Lateral resurfacing (elbow) Partial resurfacing of the elbow with a humeral surface replacement component used with a lateral resurfacing head inserted with or without cement.
Levy Additional payment placed on the sales of specific hip, knee, ankle, elbow, and shoulder implants to cover the costs associated with the ongoing operation and development of the NJR.
Linkable percentage Linkable percentage is the percentage of all relevant procedures that have been entered into the NJR, which may be linked via NHS number to other procedures performed on the same patient.
Linkable procedures Procedures entered into the NJR database that are linkable to a patient's previous or subsequent procedures by the patient's NHS number.
Linked total elbow Where the humeral and ulnar parts of a total elbow replacement are physically connected.
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LHMoM Large head metal-on-metal. Where a metal femoral head of 36mm diameter or greater is used in conjunction with a femoral stem, and is articulating with either a metal resurfacing cup or a metal liner in a modular acetabular cup. Resurfacing hip replacements are excluded from this group.
LMWH Low molecular weight Heparin. A blood-thinning drug used in the prevention and treatment of deep vein thrombosis (DVT).
M
MDS Minimum dataset, the set of data fields collected by the NJR. Some of the data fields are mandatory (i.e. they must be filled in). Fields that relate to patients' personal details must only be completed where informed patient consent has been obtained.
MDS 1 (MDSv1) Minimum dataset version one, used to collect data from 1 April 2003. MDS 1 closed to new data entry on 1 April 2005.
MDS 2 (MDSv2) Minimum dataset version two, introduced on 1 April 2004. MDS 2 replaced MDS 1 as the official data set on 1 June 2004.
MDS 3 (MDSv3) Minimum dataset version three, introduced on 1 November 2007 replacing MDS 2 as the new official data set.
MDS 4 (MDSv4) Minimum dataset version four, introduced on 1 April 2010 replacing MDS 3 as the new official dataset. This dataset has the same hip and knee MDS 3 dataset but includes the data collection for total ankle replacement procedures.
MDS 5 (MDSv5) Minimum dataset version five, introduced on 1 April 2012 replacing MDS 4 as the new official dataset. This dataset has the same hip, knee and ankle MDS 4 dataset but includes the data collection for total elbow and total shoulder replacement procedures.
MHRA Medicines and Healthcare products Regulatory Agency – the UK regulatory body for medical devices.
Minimally-invasive surgery Surgery performed using small incisions (usually less than 1Ocm). This may require the use of special instruments.
Mixing and matching Also known as 'cross breeding'. Hip replacement procedure in which a surgeon chooses to implant a femoral component from one manufacturer with an acetabular component from another.
Modified Polyethylene Any component made of polyethylene which has been modified in some way in order to improve its performance characteristics. Some of these processes involve chemical changes, such as increasing the cross-linking of the polymer chains or the addition of vitamin E and/or other antioxidants . Others are physical processes such as heat pressing or irradiation in a vacuum or inert gas.
Modular Component composed of more than one piece, e.g. a modular acetabular cup shell component with a modular cup liner, or femoral stem coupled with a femoral head.
Monobloc Component composed of, or supplied as, one piece, e.g. a monobloc knee tibial component.
N
Nelson-Aalen estimator An estimate of the cumulative hazard rate.
NHS National Health Service.
NICE National Institute for Health and Care Excellence.
NICE benchmark See ODEP ratings.
NJR National Joint Registry for England, Wales and Northern Ireland. The NJR has collected and analysed data on hip and knee replacements since 1 April 2003, on ankle replacements since 1 April 2010 and on elbow replacements and shoulder replacements since April 2012. It covers both the NHS and independent healthcare sectors to ensure complete recording of national activity in England, Wales and Northern Ireland.
NJR Centre National coordinating centre for the NJR.
NJR StatsOnline Web facility for viewing and downloading NJR statistics on www.njrcentre.org.uk
O
ODEP Orthopaedic Data Evaluation Panel of the NHS Supply Chain. www.odep.org.uk
National Joint Registry for England, Wales and Northern Ireland | 10th Annual Report
237www.njrcentre.org.uk
ODEP ratings ODEP ratings are the criteria for product categorisation of prostheses for primary total hip replacement against benchmarks. The letter represents the strength of evidence and the number the length of time in years during which the implant has been studied. The full benchmark is 10A and the entry is at 3 years with progression through 5 and 7 years. Pre-entry submissions are also recorded. “A” represents strong supporting evidence for the use of the prosthesis, “B” less strong but acceptable evidence. All implants that are used without a 10-year benchmark should be followed up closely.
OPCS-4 Office of Population, Censuses and Surveys: Classification of Surgical Operations and Procedures, 4th Revision – a list of surgical procedures and codes.
Outlier Data for a surgeon, unit or implant brand that falls outside of the defined control limits.
P
Pantalar (ankle) Affecting the whole talus, i.e. the ankle (tibio talar) joint, the subtalar (talo calcaneal) joint and the talonavicular joint.
Patella resurfacing Replacement of the surface of the patella (knee cap) with a prosthesis.
Patello-femoral knee Procedure involving replacement of the trochlear and replacement resurfacing of the patella.
Patello-femoral prosthesis Two-piece knee prosthesis that provides a prosthetic (knee) articulation surface between the patella and trochlear.
Patient consent Patient personal details may only be submitted to the NJR where explicit informed patient consent has been given or where patient consent has not been recorded. If a patient declines to give consent, only the anonymous operation and implant data may be submitted.
Patient physical status See ASA.
Patient procedure Type of procedure carried out on a patient, e.g. primary total prosthetic replacement using cement.
Patient-time The summation of time (in years) for a cohort of primary procedures where the time is measured from the primary date to either date of revision, date of patient's death or analysis date (last observation date).
PDS The NHS Personal Demographics Service is the national electronic database of NHS patient demographic details. The NJR uses the PDS Demographic Batch Service (DBS) to source missing NHS numbers and to determine when patients recorded on the NJR have died.
PEDW Patient Episode Database for Wales. The Welsh equivalent to Hospital Episode Statistics (HES) in England.
Poisson distribution This distribution expresses the probability of a number of relatively rare events occurring in a fixed time if these events occur with a known average rate and are independent of the time since the last event. It is a special case of the binomial distribution in that it models discrete events.
Primary hip/knee/ankle/elbow/shoulder replacement
The first time a total joint replacement operation is performed on any individual joint in a patient.
Prosthesis Orthopaedic implant used in joint replacement procedures, e.g. a total hip, a unicondylar knee, a total ankle, a reverse shoulder or a radial head replacement.
PROMs Patient Reported Outcome Measures.
PTIR Patient-Time Incidence Rate. This is the rate of occurrences of an event (i.e. revision) for a given total time at risk.
R
Radial head component (elbow) Part of a partial elbow joint that is inserted into the radius (outer lower arm bone) of the patient to replace the articulating surface of the radial head. May be monobloc or modular.
Resurfacing (hip) Resurfacing of the femoral head with a surface replacement femoral prosthesis and insertion of a monobloc acetabular cup, with or without cement.
Resurfacing (shoulder) Resurfacing of the humeral head with a surface replacement humeral prosthesis inserted, with or without cement.
Reverse shoulder replacement Replacement of the shoulder joint where a glenoid head is attached to the scapula and the humeral cup to the humerus.
Revision burden The proportion of revision procedures carried out as a percentage of the total number of surgeries on that particular joint.
Revision hip/knee/ankle/elbow/shoulder replacement
Operation performed to remove (and usually replace) one or more components of a total joint prosthesis for whatever reason.
238 www.njrcentre.org.uk
S
Shoulder hemiarthroplasty Replacement of the humeral head with a humeral stem and head or shoulder resurfacing component which articulates with the natural glenoid.
Single-stage revision A revision carried out in a single operation.
Subtalar joint (ankle) The joint between the talus and the calcaneum.
Surgical approach Method used by a surgeon to gain access to, and expose, the joint.
Survivorship analysis A statistical method that is used to determine what fraction of a population, such as those who have had a particular hip implant, has survived unrevised past a certain time. See Kaplan-Meier.
T
Talar component Portion of an ankle prosthesis that is used to replace the articulating surface of the talus at the ankle joint.
TAR Total ankle replacement (total ankle arthroplasty). Replacement of both tibial and talar surfaces, with or without cement.
TED stockings Thrombo embolus deterrent (TED) stockings. Elasticised stockings that can be worn by patients following surgery and which may help reduce the risk of deep vein thrombosis (DVT).
THR Total hip replacement (total hip arthroplasty). Replacement of the femoral head with a stemmed femoral prosthesis and insertion of an acetabular cup, with or without cement.
Thromboprophylaxis Drug or other post-operative regime prescribed to patients with the aim of preventing blood clot formation, usually deep vein thrombosis (DVT), in the post-operative period.
Tibial component (knee) Portion of a knee prosthesis that is used to replace the articulating surface of the tibia (shin bone) at the knee joint. May be modular or monobloc (one piece).
Tibial component (ankle) Portion of an ankle prosthesis that is used to replace the articulating surface of the tibia (shin bone) at the ankle joint.
TKR Total knee replacement (total knee arthroplasty). Replacement of both tibial and femoral condyles (with or without resurfacing of the patella), with or without cement.
Total condylar knee Type of knee prosthesis that replaces the complete contact area between the femur and the tibia of a patient’s knee.
Treatment centre Treatment centres are dedicated units that offer elective and short-stay surgery and diagnostic procedures in specialties such as ophthalmology, orthopaedic and other conditions. These include hip, knee, ankle, elbow, and shoulder replacements. Treatment centres may be privately funded (independent sector treatment centre – ISTC). NHS Treatment Centres exist but their data is included in those of the English NHS Trusts and Welsh Local Health Boards to which they are attached.
Trochanter Bony protuberance of the femur, found on its upper outer aspect.
Trochanteric osteotomy Temporary incision of the trochanter, used to aid exposure of hip joint during some types of total hip replacement.
Two-stage revision A revision procedure carried out as two operations, often used in the treatment of deep infection.
Type (of prosthesis) Type of prosthesis is the generic description of a prosthesis, e.g. modular cemented stem (hip), patello-femoral joint (knee), talar component (ankle), reverse shoulder (shoulder) and radial head replacement (elbow).
U
Ulnar component (elbow) Part of a total elbow joint that is inserted into the ulna (inner lower arm bone) of the patient to replace the articulating surface of the ulna. May be linked or unlinked.
Uncemented See cementless.
Unicondylar arthroplasty Replacement of one tibial condyle and one femoral condyle in the knee, with or without resurfacing of the patella.
Unicondylar knee replacement See Unicondylar arthroplasty.
Unilateral operation Operation performed on one side only, e.g. left hip.
Unlinked total elbow Where the humeral and ulnar parts of a total elbow replacement are not physically connected.
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NJR Centre contact details
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The National Joint Registry (NJR) produces this report using data collected, collated and provided by third parties. As a result of this the NJR takes no responsibility for the accuracy, currency, reliability and correctness of any data used or referred to in this report, nor for the accuracy, currency, reliability and correctness of links or references to other information sources and disclaims all warranties in relation to such data, links and references to the maximum extent permitted by legislation.
The NJR shall have no liability (including but not limited to liability by reason of negligence) for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the data within this report and whether caused by reason of any error, omission or misrepresentation in the report or otherwise. This report is not to be taken as advice. Third parties using or relying on the data in this report do so at their own risk and will be responsible for making their own assessment and should verify all relevant representations, statements and information with their own professional advisers.
Every effort was made at the time of publication to ensure that the information contained in this report was accurate. If amendments or corrections are required after publicaton, they will be published on the NJR website at www.njrcentre.org.uk where the document is available to download in PDF format.
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