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LCS Total Knee Arthroplasty

LCS Total Knee Arthroplasty. James M. Steinberg, D.O. Garden City Hospital. Introduction. Mobile bearing knee Low contact stress Designed by Frederick Buechel, M. D. & Michael Pappas, PhD Address the problems of tibial loosening and polyethylene wear First implanted in 1977

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LCS Total Knee Arthroplasty

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  1. LCS Total Knee Arthroplasty James M. Steinberg, D.O. Garden City Hospital

  2. Introduction • Mobile bearing knee • Low contact stress • Designed by Frederick Buechel, M. D. & Michael Pappas, PhD • Address the problems of tibial loosening and polyethylene wear • First implanted in 1977 • Approximately 39,000 implanted each year world- wide • Few clinical reports on long-term results

  3. Evolution of the LCS • 1974: Cylindrical ankle prosthesis • failed due to lack of axial rotation (Geomedic Knee) • 1974: Floating socket shoulder • frequent dislocations • 1976: New Jersey Mark I knee • Anterior femoral flange • Good results • Lacked adequate rollback

  4. LCS • New Jersey Mark II • Mobility with congruency • Patella • All poly • Metal backed rotating bearing • Tibial component • PCL sparing: meniscal bearing implant • PCL sacrificing: rotating platform implant

  5. l Mobile Bearing Design • Prior to 1977, hinged TKA which allow flexion & extension • Rotation • Curved-on-flat femoral-tibia articulation • High contact stresses & increased wear ~ ~ ~

  6. Mobility vs Congruity • LCS • Large surface area of contact • Low contact stress at metal-plastic interface • Low poly wear

  7. Biomechanics • Normal knee : • Majority of rotation occurs laterally • Both condyles pivot about the intercondylar eminence as the center of rotation • Full extension; zero degrees of rotation • 90 degrees of flexion; 30 degrees rotation • PCL tightens on flexion, rollback of femur on the tibia • ACL tightens on extension, forward roll of the femur on the tibia

  8. Surgical Concepts • Balanced flexion & extension gaps, (Insall & Freeman) • Equal soft tissue tension medially & laterally in both flexion & extension • Stable knee throughout active & passive ROM • Stability maintains contact pressure on mobile bearings • Protects against subluxations & dislocations

  9. Surgical Concepts • Tibia cut first approach • Establish flexion gap & then match extension gap • Cut with a posterior inclination parallel to anatomic inclination • Provides compressive loading of the tibial components • Avoids shearing associated with perpendicular plane resections

  10. Surgical Concepts • Femoral cuts are referenced from resected tibia • Slight external rotation of femoral component • Allows resections to parallel the proximal tibia with collateral ligaments tensioned • Provides stable tracking position for patella

  11. Surgical Concepts • LCS patellar components are fully congruent • Curve of the femoral component matches that of the patella • Patella resection • Level of quadriceps & patellar tendon insertion • Preserves sufficient bone stock & blood supply • Remnant of 13 to 15mm

  12. Wear • Tibial component • Polished cobalt chrome molybdenum tray • Rigid insert/tray locking mechanism • Retrieval of mobile bearing designs with polished trays • Little wear of back insert surface • Minimal tibial metaphyseal osteolysis • Highly congruent “other” articulation minimal wear with polishing Ray Wasielewski,MD, DePuy Publication, 1996

  13. Wear • 562 LCS TKAs with rotating platform • Polished tibial tray • 2 – 10 year follow up • Only ONE knee revised for poly wear Barry Sorrells, MD, data presented at Mobile Bearing Meeting, 1995

  14. New Jersey Orthopedic Hospital Knee Evaluation • Cumulative Scores: • 85-100 Excellent • 70-84 Good • 60-69 Fair • 0-59 Poor

  15. Clinical Review • 1405 LCS TKA 3 month – 5 year follow up • July 1977- april 1984 • 1167 pts with 15 different surgeons • 447 meniscal bearing & 820 rotating platform • 50 revision components & 58 unicompartmental • Mean knee evaluation scores excellent or good at all follow up evaluations 12 months – 5 years • Brantigan, Buechel, Jardon, Johnston, Jones, Keblish, Lewallen, Miller, Olson, Sawyer, Smith, Sorrells, Weaver, Wiedel, Wyatt, 1987

  16. Clinical Results: PCL Retaining LCS • 963 TKA were followed for 6 years • All pts had non-inflammatory arthritis • 409 cemented & 554 uncemented • Knee evaluation scores: • 93.1 uncemented & 91.8 cemented • ROM: • Avg. 118 degrees uncemented & 105 cemented

  17. Clinical Results: PCL Retaining LCS • Complications: • Low in both groups (4.3% uncemented & 7.6% cemented) • Cemented group higher number of tibial loosening • Overall no difference in clinical evaluation scores • Davenport, Friddle, Hastings, Peoples, Voorhoost, DePuy Publication,1992.

  18. Clinical Results: Cruciate Sacrificing LCS • 836 TKA were followed for 6 years • All pts non-inflamatory arthritis • 560 cemented & 276 uncemented • Knee evaluation scores: • 90% good or excellent at 6 yrs uncemented • 100% good or excellent at 6 yrs cemented • ROM: • 102 degrees uncemented • 106 degrees cemented

  19. Clinical Results: Cruciate Sacrificing LCS • No differences in complication rates • Six year survivorship: • 96.3% uncemented • 88.2% cemented • Deemed not statistically significant • Davenport, Friddle, Hastings, Peoples, Voorhoost, DePuy Publication,1992.

  20. Clinical Results: Two – Eight Year Evaluation • 275 LCS TKA • 214 PCL sparing & 51 cruciate sacrificing • 170 cementless & 105 cemented • Knee scores increased from 53 to 88 • Mean ROM 114 degrees • Keblish et al, Orthopaedics International Edition, Jan/Feb/Mar,Vol 1, No 2, 1993.

  21. Clinical Results: Ten Year Evaluation • 357 LCS TKA • 149 cemented • 66 rotating platform, 0 PCL retaining, 34 bicruciate retaining, 7 unicompartmental, & 42 revisions • 81 primary knees; 95% good or excellent results • Avg ROM: 124 degrees • Fair and poor results seen in multiply operated and implant revision cases

  22. Clinical Results: Ten Year Evaluation • 208 noncemented • 71 rotating platform, 49 PCL retaining, 38 bicruciate, 12 unicompartmental, & 38 revisions • 109 primary knees; 98% good or excellent results • Avg ROM 112 degrees • Again most of the poor results were in revision/multiply operated pts • Buechel & Pappas, Orthopedic Clinics of North America, Vol.20, No.2, April 1989.

  23. Clinical Results: Long Term Outcomes • 665 primary knees • Avg. pt age 70 • All noncemented, cruciate sacrificing rotating platform implants • 11 year surviorship 94.7% • 98% good to excellent knee evaluation scores • 13 revisions • 8 for preventable surgical error (malposition) • Sorrels, Orthopedics, Vol.19, No.9, Sept. 1996.

  24. Cruciate Retaining vs Sacrificing • Cementless implants • 147 PCL retaining & 44 sacrificed • Minimum 5 year follow up • Meniscal bearing: • 95% with nonexistent or occasional pain • Mean ROM 120 degrees • Knee score avg 93.2 • 5 required revision,98% overall seven year survival rate

  25. Cruciate Retaining vs Sacrificing • Rotating platform: • 93% with nonexistent or occasional pain • Mean ROM 108 degrees • Knee score avg 87.6 • 0 required revision, 100% overall seven year survival rate • Stiehl & Voorhost, The American Journal of Orthopedics, Vol.28, No.4, Apr.1999.

  26. Cemented Rotating Platform TKA • Nine to twelve year follow up • 119 TKA in 86 pts • Avg. age 70 (37-88) • 66 knees were available for follow up at 9-12yrs • No disloactions or revisions • Avg ROM 102 degrees • No evidence of periprosthetic osteolysis or loosening • Callaghan et al., JBJS, Vol. 82, No. 5, May 2000.

  27. Conclusions • LCS has a long standing track record • Anatomic congruent mobile design • Based on sound principles of soft tissue balancing • Extension gap MUST equal flexion gap • Preserves maximum bone stock • Addresses premature poly wear and prosthetic loosening seen in other systems

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