P r o d u c t R a t i o n a l e

SO MUCH BEHIND IT,

SO FAR AHEAD.

MOBILE BEARING KNEE SYSTEM

The LCS ® Total Knee System was

key in establishing the fundamental

design principles of low contact

stress and bearing mobility which

are now embraced by the majority

of today’s implant manufacturers.1

It was the first design to combine

congruency with mobility in a

tri-compartmental knee implant,

and it was the first mobile bearing

system to undergo multi-centre

clinical evaluation before its release.

Now, with over 23 years of clinical

experience, the LCS ® Total Knee

System has an unparalleled record

of success.

Low contact stress at the patello-

femoral and femoro-tibial bearing

interfaces has reduced the potential

for catastrophic polyethylene damage

as a cause of failure. Post-operative

self-alignment of the mobile bearings

maintains extensive bearing contact

and diffuses the torsional and

shearing forces that can lead to

implant loosening.

The incidence of patello-femoral

complications, a common cause

of re-operation after total knee

arthroplasty, is reported in notably

few cases throughout extensive

clinical follow up. 2 - 9

The LCS® utilises a single tibial tray

which carries both posterior cruciate

retaining and posterior cruciate

sacrificing bearing options, simplifying

implant selection and allowing intra-

operative choice.

The proven design of the LCS®

has been adopted world-wide and,

in LCS® Complete, the system range

is extended and the design is refined

to take full account of anthropometric

differences and size variations.

By listening to surgeons and by

learning from the unique clinical

experience of LCS®, we continue to

lead through considered innovation.

SO MUCH BEHIND IT, SO FAR AHEAD

We listen, we learn, we lead

1

Proven. The LCS® femur has remainedunaltered for over twenty-three years.Its external shape was developed for optimal congruency with the tibial insert, during the load bearingphase of the gait cycle. Internal geometry of the femoralcomponent is designed to minimisethe amount of bone to be resected. It incorporates a 15˚distal angle tocompensate for femoral bow and the physiogical posterior slope of the tibia. This allows flexion andextension gaps to be equalised as the femur is resected. Proven fixation interface options arealso retained.10, 11 LCS® Complete offerstextured components for cementedimplantation and extensivelyPorocoated patella, femoral and tibialcomponents for cementless fixation.

Refined. Clinical experience, togetherwith global anthropometric data hasled to the development of a widerrange of femoral sizes, with a slightlynarrower and longer anterior flange.This achieves a closer match with thenatural femoral anatomy for morepatients. By avoiding overhang, thepotential for irritation of the collateralligaments is reduced. Internal geometryof the LCS® Complete femur featuresa straight trochlea cut. This makesbone resection more straightforwardand increases the fixation surfacearea. Shallower graft pockets bringthe Porocoat®- to -bone interface into closer apposition, and refinedlocation pegs facilitate extraction.Medial and lateral impaction slotsimprove instrument location foraccurate implantation.

Straight trochlea cut

Proven bearing geometry Smooth location pegs

2

Shallow graft pockets

Refined anterior flange

Shallow graft pocketsbring fixation interfacesinto closer apposition.

Impaction slots for preciseinstrument interlock.

Cemented and cementless fixation.Extensive Porocoat® coverage ofcementless interface.

Straight trochlea cutmakes femoral resectionstraightforward.

Extended range of femoral sizesincluding medium and extra large.

Refined anterior flange for a closerfemoral match for more patients.

ANATOMICALLY REFINED FEMORAL GEOMETRY

3

Proven. The LCS® Knee was designedto overcome the damaging effects ofcomponent wear and loosening. The LCS® Complete has congruentfemoral and tibial mobile bearingsurfaces which diminish contactstresses within the polyethyleneinsert and diffuse shear and torsionalloosening forces.13, 14

The sagittal and coronal curves of thefemur reflect natural condylar geometry.Extensive bearing congruency occursin extension, at heel strike, andthroughout the loaded phase of thegait cycle. It is at this stage, whenjoint force is at its highest and like the normal knee, the LCS® tibialbearing is fully congruent with thelargest radius of the femoral condyle,cushioning the impact of the force.This is an important factor in the lifeof a tibial bearing since walkingaccounts for approximately 90% ofloaded joint function.15

Posteriorly, the S3 and S4 radii reduce to allow full flexion and minimiseconstraint in deep flexion.

S1

S2S3

S4

Congruent bearing contact

Extensive area contact

The S2 curve of the femur ensuresthat maximum congruency at thefemoral tibial bearing interface occurswhen peak contact pressures are attheir highest during the loadedphase of the gait cycle.

• 100% Survivorship at 8 to 12 Years2

• 94.7% Survivorship at 11 Years4

• 94.6% Survivorship at 9 Years5

• 96% Survivorship at 4 to 8 Years9

• 97.4% of Knees Rated Good/Excellent at 8 Years9

4

“The LCS® Rotating Platform wasfound to have the largest primary contact areas, generating the lowestcontact stresses. At the distal interface,LCS® was also found to have thesmallest areas of stresses above 2 MPa.”12

900

800

700

600

500

400

300

200

100

0

Con

tact

are

a m

m2

Comparison of contact areas(above 2 MPa) at 0˚ flexion

Contact stress(contact area: 877 mm2 )

Bearing congruency in the coronalplane produces extensive area contactto diffuse damaging contact stresses.

Congruent bearing contact is maintained during varus/valgus lift-offand edge contact is avoided.

LCS®

Competitor mobile bearing knee

Fixed bearing knee

LCS® bearing contact areamaintains stress levels wellwithin the recommended limitsof the bearing material.

PROVEN BEARING GEOMETRY

12, 16

5

Proven. The LCS® polyethylenepatella bearing surface remains fullycongruent at its interface with thesingle radius S2 curve of the femur,from approximately 15˚ to 110˚where compressive loads are highest.The bearing is free to rotate as ittracks along the deep sulcus groove,and the patella follows a naturalserpentine motion in response to the differential pull of the quadracepsmuscles. A sulcus groove angle of 130˚ reflects the anatomy of thenormal patella.

The femoral shape provides acongruent path for the unresurfacedpatella. More importantly, in thesagittal plane, the unresurfacedpatella articulates with a constantradius of curvature (the S2 radii ofthe LCS® Complete femur).Remodelling of the patella is facilitatedunder compression by the constancyof the femoral arc. The clinical outcome is notcompromised with the LCS®, whetheryou retain or resurface the patella.

130˚

The coronal geometry of the bearinginterface provides medial-lateral stability.

The single S2 curve of the femurensures maximum patella congruencyfrom 15˚ through 110˚.

The coronal profile of the femoralcomponent provides a congruentgroove for the natural patella.

Choice of metal-backed or all polyethylene patella options.

Congruency is maintained on one condyle, even if the patella is malaligned intra-operatively.

Minimal biological remodelling isneeded for the natural patella toadapt to the large S2 single radiusof the femoral component.

S1

S2S3

S4

• Using a modified 100-point HSS score 94.7% of patients recorded scores of excellent or good (2 to 10 years follow up).17

• Low rate of patello-femoral complications -94.7% survivorship at 11 years .4

• Less than 1% of patella complications at 10 years.16

• No difference in clinical outcome when the patella is resurfaced or retained.18

• 94.6% good to excellent clinical score (long-term results for 1777 cases, patella non-resurfaced).19

6

Proven patella mobile bearing

Three peg fixation

Extended anterior flange

REDUCING PATELLO-FEMORAL COMPLICATIONS

7

Proven. Two mobile bearing optionsare available to the surgeon: therotating platform (RP) bearing andthe anterior-posterior glide (APG)bearing. As its name suggests, the RPoption provides rotational bearingmovement to diffuse torsionalloosening forces. Bearing depth andcongruency serve to stabilise theimplant when the posterior cruciateligament (PCL) is sacrificed. If the PCL is retained, an APG bearing andguide arm may be implanted. TheAPG bearing provides both rotationand translation and, in combinationwith a physiologic posterior slope on

the tibia, allows roll-back to occur asthe knee flexes. Post-operatively, theknee can self-align within the capsuleto maintain congruent bearing contact.No mechanical stops or pegs are used in the design and the implantis naturally stabilised and constrainedby the medial and lateral collateralligaments. During motion, the bearingglides smoothly along the guide arm,avoiding potentially damaging contactstresses. The choice of RP or APGbearings may be made intra-operatively.

Refined. All LCS® Completepolyethylene bearings are manufacturedfrom GUR 1020 polymer. Gamma foilsterilised, GUR 1020 has a modified,more stable molecular structure withincreased crosslinking, increasedhydrogen recombination and reducedoxidative chain scission. Thesechanges produce a bearing that hasincreased resistance to both abrasiveand adhesive wear.20, 21

The shape of the bearing is alsorefined. Each radiused edge of thetibial insert is smoothed and blendedto avoid soft tissue irritation.

Smooth radiused edges

Proven conical bearing

GUR 1020 polyethylene

8

A reduction in the anterior profile of the APG bearing reduces thepotential for impingement of thepatello-femoral tendon and increasesthe range of bearing translation. Thetibial bearings are also given refinedanterior recesses to avoid patellacontact in flexion.An important refinement in conebearing shape brings additionalstability to the bearing when usedwith the M.B.T. revision tray, resultingin a seamless transition from primaryto revision surgery.

Refined APG anterior profile

Increased distal stability

Guide arm allows smoothtranslation of the bearing.

Proven cone bearing on APG guide arm.

The LCS® RP bearing turns to accommodate axial rotation. The APG bearing accommodates axial rotation andtranslates in flexion allowing natural femoral rollback.

ADVANCED BEARING DESIGN

9

Proven. The highly polished superiorsurface of the tibial tray is designed to facilitate bearing articulation andminimise polyethylene wear.22 Itscentral inner cone is also polished,allowing the polyethylene bearing torotate freely. Conical geometryprovides stability under lateral thrust.Simulator tested to 3 million cycles,the APG cone bearing withstood lateralthrust in excess of that normallyexperienced by the natural knee, with minimal polyethylene wear.23

The outer cone of the tray providesstability at the implant to bone fixationinterface.2, 4, 5, 9

Refined.The curved DePuy M.B.T. tray achieves maximum coverage of posterior cortical bone and its smooth posterior notch allows a PCL retaining bone block to be preserved.The choice of sizes optimisesprosthetic fit and fixation for eachpatient. Bearing cone rotation axes are also optimised to make tibialalignment common for primary andrevision procedures. External conegeometry increases proportionatelybetween the eight sizes of tray,ensuring a ‘no compromise’ approachto preparation and fit. In addition to the standard ribbedstem, the LCS® Complete MobileBearing Knee System offers thesurgeon a cemented and cementlesskeeled option.

Increased range of tray sizes.

Retrieval analysis demonstratedreduced wear at the secondary articulating surface of the LCS® Knee.20

2.00

1.75

1.50

1.25

1.00

M.B.T. Cemented Tray

M.B.T. Porocoat® Tray

Secondary articular surface wear

LCS®

Average for fixed bearing designs

• No incidence of loosening or osteolysisat the 9 to 12 year interval .2

• Survivorship relating to mechanical loosening of fixation of any componentat 8 year interval was 99%.5

• Low incidence of revision at 4-8 year interval.9

• No aseptic loosenings at 10 years.4

1.74

1.45

10

Polished superior surface

Anatomical profile

Optimised bearing axis

Refined posterior notch

M.B.T. Cemented Keel Tray

M.B.T. Porocoat® Keel Tray

STABILITY WITH CHOICE

11

Proven. The LCS® surgical techniqueis a key factor in the system's recordof outstanding success. Balancedflexion and extension gaps ensureequal collateral tension in all phasesof movement, for maximum implantstability. The rectangular flexion gapis associated with an increased rangeof motion and a reduced rate ofintra-operative retinacular releaseand post-operative tibial pain.24

The tibia is cut at 90 degrees to itslong axis in the coronal plane, and a

physiologicposterior slopeis created in thesagittal plane.After theappropriate softtissue releases,to assure longleg alignment,

an AP cutting block is positioned onthe femur. This is rotated relative to the previously cut tibia to ensure a rectangular flexion gap withappropriate ligament tension andexternal rotation. Following anteriorand posterior cuts, a distal femoral cut is made to produce an extensiongap matching the flexion gap. A spacer block is used to confirm the dimension and check medial and lateral compartment tension. When the flexion and extension gaps are matched, a single guide isused to finish the remaining femoralcuts. Six instrument trays contain allfemoral and tibial sizes.The Milestone™ Instruments nowoffer the option of glacier ceramiccutting guides. The zirconia ceramicrails improve cut accuracy andreduce metal debris.

12

A femoral guide positioner is used toestablish the rotation of the AP cuttingblock and to determine the final polyethylene bearing thickness.

Resect the tibia using the chosen 7 or 10 degree cutting block.

A spacer block is used to ensurethat a well tensioned, rectangularflexion gap has been created.

The spacer block can also be usedto check long limb alignment, usingan extramedullary rod.

UNIQUE SURGICAL PHILOSOPHY

13

Cat No: 9080-73-000

The components comprising the Complete APG are protected by European patent O 519 873 B1, USA patent 5395401, Japanese patent 2741 644 and Swiss patent 689539 which are licensed to DePuy International Limited by Mr André R. Baehler, Kapsteig 44, CH-8032, Zurich, Switzerland.

This publication is not intended for distribution in the USA

LCS® and Porocoat® are registered trademarks and Milestone™ is a trademark of DePuy Orthopaedics, Inc.

© 2001 DePuy International Limited

0086

DePuy International LtdSt Anthony’s RoadLeeds LS11 8DTEnglandTel: +44 (113) 270 0461Fax: +44 (113) 272 4191

References:

1. Insall JN. Adventures in Mobile-Bearing Knee Design: A Mid-life Crisis. Orthopedics, Vol 21, 1993.

2. Callaghan JJ, Squire MW, Goetz DD, Sullivan PM, Johnston RC. CementedRotating- Platform Total Knee Replacement.A Nine to Twelve Year Follow-Up Study. J Bone Joint Surg, 82-A, No. 5, 2000.

3. Buechel FF, Pappas MJ. Long TermSurvivorship Analysis of Cruciate-Sparing versus Cruciate-Sacrificing Knee ProsthesisUsing Meniscal Bearings. Clin Orthop and Rel Res, 260, 1990.

4. Sorrells BR. Primary Knee Arthroplasty: Long-Term Outcomes. The Rotating PlatformMobile Bearing TKA. Orthopedics, 19, 1996.

5. Jordan LR, Olivo JL, Voorhorst PE.Survivorship Analysis of Cementless MeniscalBearing Total Knee Arthroplasty: A 14-YearFollow-Up. Clin Orthop and Rel Res, 338, 1997.

6. Buechel FF, Pappas MJ, New Jersey LowContact Stress Knee Replacement System.Ten-Year Evaluation of Meniscal Bearings.Orthop Clin North Am, April, 1989.

7. Hamelynck K J. 15 Years Experience with theLow Contact Stress (LCS) Total Knee Prosthesisin Osteoarthritis and Rheumatoid Arthritis.Paper presented at the InternationalConference on Knee Replacement. I MECh E,London, 22 - 24 April 1999.

8. Keblish PA, Scheri C, Ward M. Evaluation of 275 Low Contact Stress (LCS) Total KneeReplacements with 2 to 8 Year Follow-Up.Orthopaedics International Edition, Vol 1,1993.

9. Sanchez-Sotelo J, Ordonez MJ, Prats SB.Results and Complications of the Low ContactStress Knee Prosthesis Using MeniscalBearings. J Arthrop, Vol 14, 1999.

10. Bobyn JD, et al. The Optimum Pore Size for the Fixation of Porous Surfaced MetalImplants by the Ingrowth of Bone. Clin Orthop and Rel Res, 150, 1980.

11. Kilgus DJ, et al. Fixation and Durability: A Comparison of 2,011 Extensively and 654Proximally Porous-Coated Femoral Implantsof One Design with 2-15 Year Follow-Up.Paper 478. Presented at the Annual Meetingof AAOS, Atlanta, 1996.

12. Morra EA, Postak PD, Greenwald AS. TheInfluence of Mobile Bearing Knee Geometryon the Wear of UHMWPE Tibial Inserts: A Finite Element Study. Orthopedic ResearchLaboratories, The Mt Sinai Medical Center,Cleveland, 1997.

13. Eckhoff DG, Metzger RG, Vandewalle MV.Malrotation Associated with Implant Alignment Technique in Total KneeArthroplasty. Clin Orthop and Rel Res, 321, 1995.

14. Lewis P, Rorabeck CH, Bourne RB, Devane P.Posteromedial Tibial Polyethylene Failure inTotal Knee Replacements. Clin Orthop andRel Res, 299, 1994.

15. Morrison JB. The Biomechanics in the Knee Joint in Relation to Normal Walking. J Biomech, Vol 3, 1970.

16. Jordan LR, Keblish PA, Collier J, Greenwald AS.Successful Use of Metal-Backed RotatingAnatomic Patella in TKA. BiomechanicalRationale and Clinical Experience, AAOS, San Francisco, USA, 1993.

17. Munzinger U, Petrich J, Boldt JG. PatellaResurfacing in Total Knee Arthroplasty Using the Metal-Backed Rotating BearingComponents: A 2 to 10 Year Follow-UpEvaluation. Published on-line atwww.dx.doi.org.

18. Keblish PA, Greenwald AS. Patella RetentionVersus Patella Resurfacing. J Bone Joint Surg,76-B, No. 6, 1994.

19. Boldt JG, Keblish P, Drobney T, Munzinger U.Patella Non-Resurfacing in TKA Using theLow Contact Stress Bearing Prosthesis: A 2 Year Study. Submitted for publication.

20. Greer KW, Jones DE. The Importance ofStandardization of Wear Test Parameters inthe Simulation of Knee Wear Mechanisms.Trans Soc Biomater, 17, 1994.

21. McKellop H, Clarke IC. Degradation and Wearof Ultra-High Molecular Weight Polyethylene:Corrosion and Degradation of ImplantMaterials. Second Symposium ASTM STP 859,AC Fraker and CD Griffin, eds, 351-68, 1985.

22. Collier J. Correspondence Relating toDifferential Wear in Fixed and Mobile BearingKnees. Data on File, DePuy International Ltd,1989.

23. Simulator Testing of the AP Glide BearingMechanism. Biomechanical EngineeringTrust. Data on file, DePuy International Ltd,1991.

24. Laskin RS. Flexion Space Configuration in TotalKnee Arthroplasty. J Arthrop, Vol 10, 1995.