VALGUS TKA. RESULTS OF 255 LCS MOBILE-BEARING TKA WITH 5 TO 15 YEAR FOLLOW-UP

Abstract

Introduction:

Correction of fixed valgus is a challenge in primary TKA. Achieving patello-femoral and femoral-tibial stability requires superficial/deep lateral side releases if non-constrained prostheses are utilized. The medial approach has disadvantages with more reported complications. The direct lateral approach, with/without tubercle osteotomy, is an approach option utilized in two reporting centers.

Methods:

255 valgus TKAs with 5- to15-year follow-up were reviewed. Demographics included 91% females, 15% rheumatoid, mean age 69. Prostheses utilized were LCS mobile-bearing (meniscal PCL-retaining/rotating PCL-sacrificing). Patella was non-resurfaced in 90%; cement-less fixation in 86%. The direct lateral approach with similar lengthening techniques was used with tubercle osteotomy in one center and osteo-periosteal joint exposure in another.

Results:

Good/excellent 91%, modified HSS score improvement 57 to 85. Deformity (12) improved < 8 to 12 points (> 15o valgus to < 5o valgus). ROM improved from mean 11o/97o to 1/110o latest. Technical/prosthetic-related complications included: 7 bearing failures (5 meniscal, 2 rotating platform), 2 aseptic loosenings (tibial), 1 patella ligament rupture and 2 screw loosenings in the osteotomy group, 1 patella re-dislocation in a 75-year-old female with dislocation since age 15 (non-osteotomy group), 2 infections, and 1 re-operation for arthrofibrosis.

Discussion/Conclusion:

Valgus TKA using LCS moveable bearings implanted via a direct lateral approach are highly successful regarding stability and patella tracking. Failures correlate with inadequate/de-stabilizing releases and meniscal PCL-retaining prostheses. Rotating bearings allow for better stability and self-adjustment of common mal-rotation variables. The lateral approach allows for direct (stepwise) lengthening releases, improved patellar tracking, and precise gap balancing.