LCS Total Knee Arthroplasty

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
Mobile Bearing Design
l

• 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

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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

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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.

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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

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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.

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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.

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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