Design Rationale - Smith+Nephew total knee … · ANTHEM Total Knee System Design Rationale 2 • The ANTHEM knee system is a total knee prosthesis with advanced femoral and tibial

Design Rationale

Supporting healthcare professionals

1 ANTHEM Total Knee System Design Rationale

ANTHEM™ Total Knee System

Table of contents

Introduction ............................................................................................. 2

Relevant Feature by Region ..................................................................... 3

Anatomic Implant Fit ................................................................................ 4

Femoral Component Design .................................................................... 12

High Flexion PS Tibial Insert Design ........................................................ 14

High Flexion CR Tibial Insert Design ........................................................ 15

Tibial Component Design ........................................................................ 16

Built on Proven Heritage .......................................................................... 19

Promoting Efficiency Through Intelligent Design ...................................... 20

2ANTHEM Total Knee System Design Rationale

• The ANTHEM knee system is a total knee prosthesis with advanced femoral and tibial anatomic design to promote improved anatomic implant fit, taking into consideration the anatomical differences among global ethnicities1

• The ANTHEM knee is based upon trusted design pedigree incorporating clinically advanced technology such as the tibio-femoral articulation and patello-femoral function equivalent to the GENESIS™ II Total Knee System, which exhibits a 98% survivorship at 15 years in a study of 89 patients2

• The ANTHEM Total Knee System coupled with ORTHOMATCH™ Universal Instrumentation Platform has been developed in conjunction with leading surgeons from Emerging Markets and Europe providing benefits by creating efficiency through intelligent design which translates into tangible value for surgeons, patients and healthcare providers

Fit for AllThe ANTHEM™ Total Knee System was designed to provide an advanced and globally relevant prosthesis and instrumentation system while being accessible to all arthroplasty surgeons and patients.

India

East Asia

Africa

South America

Europe and North America

Middle East


DURAHONE™ Advanced Finishing tibial polished surface

Bone conserving PS box

Low profile anterior femoral flange

Optimised ML femoral component

Asymmetric tibial base, shorter, medial stem

ORTHOMATCH™ instrument platform

Fit for ALLRelevant Feature by Region

High flexion insert

S-shaped trochlear groove


Anatomic Implant Fit

Understanding Size and Shape of the Knee Anthropometry, the study of the measurements and proportions of the human body, is relevant to knee arthroplasty. A better understanding of the significant differences in size and shape of patients’ knees may lead to being able to improve implant fit, and thereby reproduce normal knee anatomy more closely. From a recent systematic review of 30 peer reviewed articles, statistically significant anatomical and morphological differences of the knee joint critical to Total Knee Arthroplasty (TKA) were found between geographical regions relating to3:

Size: Antero-Posterior height and Medio-Lateral width of the femur and tibiaShape: Aspect Ratio between Medio-Lateral width and Antero-Posterior height of femur and tibia

Due to historical and incomplete design data, many contemporary TKA implants do not adequately address these fundamental differences in shape and size. This means that when addressing patients from different ethnicities, there may be a compromised implant fit.4-7


Implications of implant fit Tibial and Femoral implant overhang greater than 3-4mm (implant larger than resected bone surface) has been correlated to a reduced ROM, reduced function, and increased post-operative pain in patients undergoing TKA.4-7 On the opposite side avoiding overhang by downsizing the implant may lead to knee instability.7 Therefore the relationship between the implant and each patient’s individual anatomy may influence the following areas that are relevant to optimising outcomes of TKA:

Implant fit - Femoral and Tibial size options to match the majority of patients - Correct shape to accommodate regional and gender differences

Surgical technique - Implant size selection to optimize bone cuts - Ligament stability and balancing

Function and longevity - Improved Kinematics (motion) - Soft tissue irritation and pain caused by prosthesis overhang - Sizing conformity to improve tribology and reduce wear

As correct implant fit contributes to clinical outcomes, an implant and instrumentation system that accommodates individual patients, reduces clinical compromise and promotes longevity is desirable.

Critical Femoral Anthropometric Measurements related to TKA

Critical Tibial Anthropometric Measurements related to TKA

Anatomic FitAnatomic Implant Fit

AP

ML

Medial AP

Lateral AP

1.0

1.1

1.2

1.3

1.4

Fem

oral

Asp

ect R

atio

(ML/

AP)

Femoral Aspect Ratio Between Ethnicities3

White Black East Asian

*Statistical Significant Difference


Aspect ratio provides a measure of relative femoral shape Aspect ratio is defined as the Medio-Lateral width divided by the lateral Antero-Posterior height of the femur or tibia. A larger aspect ratio corresponds to a larger ML dimension for a given AP size, while a smaller aspect ratio corresponds to a smaller ML dimension for a given AP size. The benefits of understanding aspect ratio include that the femoral shape can be predicted and can act as guide to femoral component size. In addition the aspect ratio provides a measure of the relative dimension of the knee between patients.

The ML width of the distal femur is primarily associated with femur length and ethnicity, not gender.3,8 Based on current evidence ‘gender specific’ designs confer no clinical benefit.3,9 However differences in aspect ratio and femoral shape for different genders have been identified between regional patient groups.3,10,11

There are differences in the shape of the knee between ethnicities

Femoral aspect ratio (ML/AP)

Smaller aspect ratio – smaller ML for constant AP

Larger aspect ratio – wider ML for constant AP

East Asian patients have a larger aspect ratio, or wider femoral ML dimension for a given AP dimension, compared to Caucasian patients.3

With an optimised trochlear and ML dimension the ANTHEM™ knee faclitates optimal fit for a wider range of shapes and sizes of the knee

42

44

46

48

50

Tibi

al A

P D

imen

sion

(mm

)

Tibial AP Dimension Between Ethnicities: Medial vs Lateral3

Caucasian Indian

Medial AP

Medial AP

Medial AP

Lateral AP

Lateral AP

East Asian

Lateral AP

Medial AP

Lateral AP


The tibial plateau is asymmetric, with a larger AP dimension medially than laterally The medial and lateral plateau have different dimensions across ethnicities

All patient groups have a larger Medial AP dimension than Lateral AP dimension.3

M L

Tibial Medial vs Lateral AP dimension

The ANTHEM™ asymmetric tibial baseplate design facilitates optimal fit for a wider range of shapes and sizes of the knee

Anatomic FitAnatomic Implant Fit

Trochlea Dimension Condylar Dimension


Optimising implant fit for all patientsPrevious TKA implant design has focused on basic Medio-Lateral measurements at the widest aspect of the femur. However evidence exists that the position of overhang may be an important contributor to postoperative pain and reduced functional outcome, especially in the Trochlea region.4-6 In cases when upsizing of the femoral component is required, such as to restore posterior femoral condylar offset, or to balance a larger flexion gap, a lack of optimized design or size options may lead to clinical compromise.4,5,12

To facilitate optimal implant fit, the ANTHEM™ knee system was designed based on the anatomical measurements of hundreds of patients globally encompassing all major geographic regions with the assistance of proprietary ADaM (Anatomical Data Mining) protocol.1 After virtual bone preparation for TKA of Smith & Nephew in-house VISIONAIRE™ Patient Matched Technology, each critical dimension of the femur related to implant fit was evaluated and analyzed:

Trochlea dimension: Width of the femur at Trochlea chamfer Condylar dimension: Width of the femur at Condylar chamfer

Trochlea Dimension - Anterior View of Femur Critical Dimensions - Lateral View of Femur Critical Dimensions – Distal View of Femur

Overhang

35

40

45

50

55

60

65

45 55 65 75

Troc

hlea

M/L

Wid

th (m

m)

A/P Height (mm)

35

40

45

50

55

60

65

45 55 65 75

Troc

lear

M/L

Wid

th (m

m)

A/P Height (mm)

European Trochlea

35

40

45

50

55

60

65

45 55 65 75

Troc

hlea

M/L

Wid

th (m

m)

A/P Height (mm)

Middle East Trochlea

35

40

45

50

55

60

65

45 55 65 75

Troc

hlea

M/L

Wid

th (m

m)

A/P Height (mm)

African Trochlea

India Trochlea

35

40

45

50

55

60

65

45 55 65 75

Troc

hlea

M/L

Wid

th (m

m)

A/P Height (mm)

China Trochlea

ANTHEM Narrow Femoral Size

ANTHEM Standard Femoral Size


Anatomic FitAnatomic Implant Fit - Design Definition

ANTHEM™ – Optimised implant fit for all patientsThe ANTHEM Total Knee System is designed to provide an optimal size range and geometry for patients from all regions, at the Trochlea, Junction, and Condylar areas of the femoral component.1

Trochlea Dimension of the resected Femur compared to ANTHEM trochlea dimension

505560657075808590

45 55 65 75

Cond

yle

M/L

Wid

th (m

m)

A/P Height (mm)

India Condyle

505560657075808590

45 55 65 75

Cond

yle

M/L

Wid

th (m

m)

A/P Height (mm)

China Condyle

505560657075808590

45 55 65 75

Cond

le M

/L W

idth

(mm

)

A/P height (mm)

European Condyle

505560657075808590

45 55 65 75

Cond

yle

M/L

Wid

th (m

m)

A/P Height (mm)

Africa Condyle

505560657075808590

45 55 65 75

Cond

yle

M/L

Wid

th (m

m)

A/P Height (mm)

Middle East Condyle

ANTHEM Narrow Femoral Size

ANTHEM Standard Femoral Size


Condylar Dimension of the resected Femur compared to ANTHEM condylar dimension

0.0

2.0

4.0

6.0

8.0

10.0

China India Japan Korea

Prpo

rtion

of o

verh

ang

>3m

m (%

) Condyle overhang between GENESIS II and ANTHEM Narrow*

GENESIS II ANTHEM Narrow

0.0

5.0

10.0

15.0

20.0

China India Japan KoreaPr

porti

on o

f ove

rhan

g >

3mm

(%)

Trochlear overhang between GENESIS™ II and ANTHEM Narrow*

GENESIS II ANTHEM Narrow

1

1


Anatomic FitAnatomic Implant Fit - In vivo testing of ANTHEM™ Fit

ANTHEM – Optimised implant fit for all patientsIn a further study, intraoperative measurements were taken from 967 TKAs for each critical dimension of the knee.13 Five regions were included in the sample: Australia, China, India, Japan, Korea. The ANTHEM Narrow and a conventional femoral trial component were compared on the prepared bone to confirm size. Implant overhang was then calculated. Clinically relevant overhang was defined as an implant dimension 3mm or greater than the measured bone dimension at the Trochlea and Condylar regions.

*The sample used Size 3-6 for direct comparison of components.


Advanced TechnologyFemoral Component Design

Low profile of the anterior flangeNarrower flange shape than GENESIS™ II, which has been shown to limit bone overhang and soft-tissue impingement in the patello-femoral trochlea region.1

Suitable for PS and CRANTHEM™ is available in both Posterior Stabilised and Cruciate Retaining options.

Anatomic femoral ML dimensionML dimension offered in Standard and Narrow femoral dimensions. All ANTHEM Femoral Components are optimized from anthropometric data from a wide range of patients to improve prosthesis fit.1

Tightly radiused symmetrical posterior condylesANTHEM includes symmetric posterior condyles allowing the surgeon to set external rotation based on patient anatomy. The design includes tibio-femoral geometry equivalent to the GENESIS II design and LEGION™ design.16

S-shaped trochlear grooveSimulates a natural femur in its movement of the patella from a lateral position in extension to midline in flexion, with potential to reduce lateral release rates to approximately 3% compared with approximately 14% for some competitive devices.14,15

Bone preserving open PS box designRemoves significantly less bone than some major competitive systems, leaving the anterior bone bridge intact for stability and strength.17Bone conserving

PS box

Tightly radiused condyles allow up to 155° flexion

Patella friendly ‘S’ curve

Low profile anterior flange

Optimized ML dimension


Advanced TechnologyFemoral Component Design

The ANTHEM™ bone bridge preserving PS box removes less bone than other PS designs Over resection of bone to accommodate PS box may result in an increase in risk of intraoperative intercondylar fractures.17,18 Leaving the anterior bone bridge intact may reduce the risk of stress risers and reduce fracture incidence.17 Intercondylar notch resection volume is significantly reduced compared to competitive systems.17

ANTHEM PS Box Design

The ANTHEM Femoral PS Box design reduces bone removal and includes one step ream through femoral trails.

ANTHEM PS Box Resection

Conventional PS Box Resection


High Flexion PS Tibial Insert Design

Based on clinically successful HeritageThe ANTHEM™ Insert design is based upon the trusted GENESIS™ II and LEGION™ designs.2,16

Chamfered anteriorRelieves tension on the patellar tendon, allowing a more natural angle of the patella and reduces potential for anterior knee pain.19

Chamfered anterior postDesigned to eliminate patellar component impingement in deep flexion; has equivalent fatigue strength to the standard LEGION PS Insert.20

Modified posterior articulationLowered posterior lip reduces contact stress and avoids edge loading in deep flexion; maintains collateral ligament tension in deep flexion; and moves the flexion contact point anteriorly and distally from the proximal edge of the posterior condyles.19

What is the benefit of a high-flex insert? Traditional Total Knee Replacement systems have been designed to deliver flexion up to 120°, which has typically been sufficient for the average patient. However, those patients who require deeper flexion because of their culture or an active lifestyle need a system that can safely accommodate flexion up to 155°.19,21 Even daily activities like stair climbing, rising from a chair, or getting out of a bathtub can require flexion greater than those usually delivered by standard TKA systems. The LEGION PS High-Flexion Insert was designed to accommodate flexion up to 155° without additional posterior condyle resection.

Chamfered anterior

Lowered posterior lip

ANTHEM PS High Flexion insert design


Based on clinically successful HeritageThe ANTHEM™ Insert design is based upon the trusted GENESIS™ II and LEGION™ designs.2,16

Deepened PCL notchAllows for smoother PCL tracking with minimal insert contact.22

Reduced posterior lipModified articulation allows for maximum flexion by minimizing cortical impingement and convexity avoids edge loading in deep flexion.19,21

Anterior conformityDished anterior design assists in A/P stability by limiting paradoxical motion (femur driving forward on tibia) during early-mid flexion.23

Anterior chamferMinimizes patellar tendon/implant impingement and allows for a more natural angle of the patella to facilitate deeper flexion and reduce the potential for anterior knee pain.19

Advanced TechnologyHigh Flexion CR Tibial Insert Design

Deepened PCL Notch

Reduced posterior lip

Anterior Chamfer

Anterior Conformity

ANTHEM™ CR High Flexion insert design

What is the benefit of a high-flex insert?Traditional total knee replacement systems have been designed to deliver flexion up to 120°, which has typically been sufficient for the average patient. However, those patients who require deeper flexion because of their culture or an active lifestyle need a system that can safely accommodate flexion up to 155°.19,21 Even daily activities like stair climbing, rising from a chair, or getting out of a bathtub can require flexion greater than those usually delivered by standard TKA systems. The LEGION CR High-Flexion Insert was designed to accommodate flexion up to 155° without additional posterior condyle resection.

ANTHEM Asymmetric Tibial BaseplateOptimizes Coverage and Rotation

3° Posterior Slope built into resection


Asymmetric tibial design allows for optimal coverage and rotation

The asymmetric shape closely matches the anatomy of the tibia for optimal cortical rim coverage and even stress distribution. This minimizes tibial rotational errors, baseplate overhang and achieves ≥ 95% bone coverage.14,24-27

Anatomic Tibial Stem and KeelProportionally medialized on the proximal tibia to align with the intramedullary canal.

Fin location and shape were designed to be stress absorbing while providing rotational resistance when the prosthesis is implanted.28,29

Tibial Component Anatomic Design

ANTHEM™ Tibial Baseplate Design

Optimal tibial positionA posterior sloped baseplate design allows for optimal loading of the tibial bone and good range of motion.30,31

Cutting the tibia with a posterior slope, as opposed to a 0° cut, provides stronger bone that may help reduce the chance of tibial baseplate subsidence.32

M L

Midline of tibial base

Stem Medialised to align with center of tibial canal

Shortened Stem


Advanced TechnologyTibial Component Material and Fixation Design

Titanium tibial baseplate delivers improved biocompatibility and biomechanical propertiesTitanium is used due to its elastic properties and relative lack of stiffness, to better match the elasticity of bone. Reducing stiffness of the implant enhances stress resistance which minimizes stress shielding, reducing the risk of bone resorption and atrophy, potentially prolonging the life of the implant.33

The ability to forge Titanium allows for a thin yet strong tibial baseplate with a maximum thickness of 2.3mm, both increasing the minimum thickness of polyethylene and improving bone conservation.

Optimised FixationThe grit blasting has been shown to improve cement interdigitation and bonding strength through its optimized surface roughness.

The cement pocket design has been shown to be optimal for cement penetration into bone and improving tibial baseplate fixation stability.

ANTHEM tibial baseplate is made of Forged Titanium with a thickness of 2.3mm, allowing optimal insert thickness and bone conservation

Grit blasted anti-rotation fin

Cement pocket

Grit blasted undersurface

Cement anti-rotation fixation features

2.3mm Ti-6Al-4V alloy


Tibial Component Design

DURAHONE™ polishing produces a visibly smoother surface and reduces insert micro-motion

Polished tibial baseplates reduce the incidence and rate of backside polyethylene wear.34 Tibial components utilizing DURAHONE polishing, coupled with the a peripheral dovetail locking mechanism, reduces insert micro-motion by 29% compared to manual polishing methods.35

ANTHEM™ Tibial Baseplate utilizing DURAHONE polishing process

ANTHEM Tibial Baseplate peripheral dovetail locking mechanism

Smith & Nephew DURAHONE Technology


Built on Proven HeritageThe tibial locking mechanism and fixation surface of the ANTHEM™ is using the proven GENESIS™ II technology

Peer Reviewed ArticleTibial Tray Thickness Significantly Increases Medial Tibial Bone Loss in Cobalt-Chromium Total Knee Arthroplasty.36 Martin et al: the Journal of Arthroplasty 32 (2017) 79-82

• Thicker CoCr tibial trays were associated with more medial bone loss than thinner Titanium designs

Peer Reviewed Article Migration of a Cemented Fixed-Bearing, Polished Titanium Tibial Baseplate at Ten Years.37

Teeter et al: the Bone and Joint Journal 2016; 98-B:616-21

• The mean migration of the tibial component was less than 0.1mm and 0.1° in all planes relative to the postoperative RSA exam.

Simplify Surgical Flow

Maximize Productivity

Optimize Asset

Utilization

Provide Value and Access


EfficiencyPromoting Efficiency Through Intelligent Design

The global healthcare system is currently under increasing pressure. While in the past enjoying rapid technological development and uptake, public healthcare systems in developed markets are now being expected to improve efficiency, reduce spending, and ultimately ‘achieve more with less’. Similarly private funders are under pressure to maximise profits and maintain competitiveness. An aging population and increase in developed world disease will continue to add further stress to already stretched surgical resources.

The ANTHEM™ Knee System and ORTHOMATCH™ Universal Instrumentation platform have been developed to reduce activities that add unnecessary cost into the orthopedic healthcare system through dedication to the following principles:

Improving implant fit by offering an optimized design and portfolio of sizes that is inspired by studies looking at the different anatomies of the human knee joint

Streamline operative flow by reducing the number of surgical steps and simplifying procedure flow

Maximize productivity by reducing tray weight through the use of using space age polymers, combined functionality, and modularity within instrument design

Optimise asset utilization by reducing comprehensive instrument set to three trays without sacrificing functionality


1. Anatomical Data Mining of CT data utilising sets from Europe, China, India, Middle East and Africa. Smith & Nephew internal report: Design control document DHF-INDG-Anatomical Analysis B.

2. Victor et al, Total knee arthroplasty at 15–17 years: Does implant design affect outcome? International Orthopaedics; 2014. 38:235–24.

3. Kim, T K, et al. “What Differences in Morphologic Features of the Knee Exist Among Patients of Various Races? A Systematic Review” Clin Orthop Relat Res (2017); 475:170–182.

4. Chung, B J et al. “Clinical Implications of Femoral Anthropometrical Features for Total Knee Arthroplasty in Koreans” The Journal of Arthroplasty 30 (2015); 1220–1227.

5. Mahoney, O M, et al. “Overhang of the femoral component in total knee arthroplasty: risk factors and clinical consequences” The Journal of Bone & Joint Surgery (2010); 92:1115-21.

6. Bonnin, M P, et al. “Mediolateral oversizing influences pain, function, and flexion after TKA” Knee Surgery & Sports Traumatology & Arthroscopy (2013); 21: 2314-2324.

7. Lim, Jason Beng Teck, et al. “Gender-specific total knee arthroplasty in Singaporean women” Journal of Orthopaedic Surgery (2015); 23:(2) 190-3.

8. Piriou, Philippe, et al. “Are gender-specific femoral implants for total knee arthroplasty necessary?” The Journal of arthroplasty (2014); 29:742-748.

9. Cheng, Tao, et al. “No clinical benefit of gender-specific total knee arthroplasty: A systematic review and meta-analysis of 6 randomized controlled trials.” Orthopaedica 2014; 85 (4): 415–421.

10. Yue B, et al. “How the Gender or Morphological Specific TKA Prosthesis Improves the Component Fit in the Chinese Population?” The Journal of Arthroplasty. (2014); 29:71-74.

11. Chin, Pak Lin, et al. “Intraoperative morphometric study of gender differences in Asian femurs.” The Journal of arthroplasty. (2011); 26 (7):984-988.

12. Hitt, Kirby, et al. “Anthropometric measurements of the human knee: correlation to the sizing of current knee arthroplasty systems.” The journal of bone & joint surgery 85.suppl 4 (2003): 115-122.

13. Kim TK, Sharma G, Liu D, Malhotra R, Zhou YX, Akagi M. “Availability of additional mediolateral implant option during TKA improves femoral component fit across ethnicities: results of a multicentre study” JBJS Open Access (2017); 18; 2(2):e0014.

14. Laskin RS, Davis J. Total knee replacement using the Genesis II prosthesis: a 5-year follow up study of the first 100 consecutive cases. Knee. 2005;12(3):163-167.

15. Yang CC, McFadden LA, Dennis DA, Kim RH, Sharma A. Lateral retinacular release rates in mobile- versus fixed-bearing TKA. Clin Orthop Relat Res. 2008;466(11):2656-2661.

16. Smith & Nephew Technical Memo DHF-K13-INDG ANTHEM Femoral Comparisons.17. Haas SB, Nelson CL, Laskin R. Posterior stabilized knee arthroplasty: an

assessment of bone resection. Knee. 2000;7:25-29.18. Lombardi Jr. AV, Mallory TH, Waterman RA, Eberle RW. Intercondylar distal femoral fracture. An unreported

complication of posterior-stabilized total knee arthroplasty. The Journal of Arthroplasty. (1995); 10:643-650.

References

19. Jain S, et al. High-Flexion Posterior-Stabilized Total Knee Prosthesis: Is It Worth The Hype? Knee Surg Relat Res 2013;25(3):100-105.

20. Morrison M, et al. Lock and PS-Post Fatigue Strengths of Highly Crosslinked Polyethylene Tibial Inserts. Bone & Joint Science. 2011:2(2).

21. Sultan P et al. Optimizing Flexion After Total Knee Arthroplasty. Clinical Orthopaedics and Related Research. (2003)Number 416, pp. 167–173.

22. Crow B, et al. Can High-Flexion Tibial Inserts Improve Range of Motion After Posterior Cruciate-Retaining Total Knee Arthroplasty? Orthopedics. 2010;33(9).

23. Massin P, Boyer P, Sabourin, M; Less femorotibial rotation and AP translation in deep-dish total knee arthoplasty. An intraoperative kinematic study using navigation. Knee Surg Sports Traumatol Arthtosc (2012) 20:1714-1719.

24. Shah S, et al, MRI Based Comparison of Tibial Bone Coverage by Five Knee Prosthesis: Anthropometric Study in Indians, J Arthroplasty. (2015); 30: 1643-1646

25. Stacey Martin MD, Alex Saurez BS, Sabir Ismaily BS, Kashif Ashfaq MD, Philip Noble PhD, Stephen J. Incavo MD, Maximizing Tibial Coverage Is Detrimental to Proper Rotational Alignment, Clin Orthop Relat Res (2014) 472:121–125.

26. Westrich GH, Haas SB, Insall JN, Frachie A. Resection specimen analysis of proximal tibial anatomy based on 100 total knee arthroplasty specimens. J Arthroplasty 1995;10:47–51.

27. Hartel MJ, Loosli Y, Gralla J, Kohl S, Hoppe S, Röder C, et al. The mean anatomical shape of the tibial plateau at the knee arthroplasty resection level: an investigation using MRI. Knee 2009;16:452–7.

28. Salehi, A. A GENESIS II Tibial Tray Design Optimization. Smith & Nephew Richards Inc., Technical Report, OR-94-77, August, 1994.

29. Salehi, A. A GENESIS II Cemented Tibial Tray Failure-Load Prediction Using the Finite Element Analysis. Smith & Nephew Richards Inc.,Technical Report, OR-95-33, April, 1995.

30. Catani F, Fantozzi S, Ensini A, Leardini A, Moschella D and Giannini S. Influence of tibial component posterior slope on in vivo knee kinematics in fixed-bearing total knee arthroplasty. J Orthop Res. 2006 Apr;24(4):581-7.

31. Dorr LD, Boiardo RA. Technical Considerations in Total Knee Arthroplasty. Clin Orthop Relat Res. 1986 Apr;(205):5-11.32. Hofmann, A.A.; Bachus, K.N.; Wyatt, R.W.B.: Effect of the Tibial Cut on Subsidence Following

Total Knee Arthroplasty. Clinical Orthopaedics and Related Research. 269, August 1991. 33. Long, M.; Rack, H.J.: “Titanium alloys in total joint replacement - a materials

science perspective”, Biomaterials, 19 (1998) 1621-1639.34. Berry DJ et al. “Knee Wear Measured in Retrievals: A polished Tray reduced wear”.

Clinical Orthopaedics and Related Research (2012); 470:1860-1868.35. Hartsell, Zane. “Micromotion Testing of the GENESIS II and JOURNEY BCS Tibial Trays with an

Automated Media Blasted Finish.” Smith and Nephew Orthopaedic Report, OR-12-113. Oct 2012.36. Martin, J R, et al. “Tibial tray thickness significantly increases medial tibial bone resorbtion in cobalt-

chromium total knee arthroplasty implants” The Journal of Arthroplasty 32 (2017): 79-8237. Teeter, M G, et al. “Migration of a cemented fixed-bearing, polished titanium tibial

baseplate (Genesis II) at ten years” The Bone & Joint Journal 2016;98-B:616-21

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Documents

Design Rationale - Smith+Nephew total knee … · ANTHEM Total Knee System Design Rationale 2 • The ANTHEM knee system is a total knee prosthesis with advanced femoral and tibial