Effect of medial epicondylar osteotomy on soft tissue balancing in total knee arthroplasty.

Balancing and surgical exposure of a severe varus knee during total knee arthroplasty (TKA) can be difficult. Use of a medial epicondylar osteotomy to solve these problems has been reported. This study compared knee stability in cadaveric specimens after TKA, after medial epicondylar osteotomy, and after conventional subperiosteal release of the medial collateral ligament (MCL). Five cadaveric knees were tested after TKA, after medial epicondylar osteotomy, and after repair of the osteotomy to compare the results to 5 cadaveric knees that underwent complete subperiosteal release of the MCL. A retrospective review of clinical cases also was performed of 118 varus knees exposed using the standard medial parapatellar approach and subperiosteal release of the MCL to compare results to the literature using a medial epicondylar osteotomy. Coronal and transverse plane laxity increased significantly at 60° and 90° flexion in the knees after medial epicondylar osteotomy. Suture repair of the osteotomy did not affect stability. The knees with MCL release had a significantly lower degree of coronal and transverse plane laxity at 60° and 90° than knees with an epicondylar osteotomy. The retrospective case review found satisfactory exposure and correct ligament balance was achieved in all cases. The findings of this study question the need for an epicondylar osteotomy in severe varus osteoarthritic knees. Because the knee remains unstable in flexion after this technique, an implant with higher constraint should be used.