Unicompartmental knee arthroplasty for osteoarthritis of the knee: remaining postoperative flexion contracture affecting overall results.

The success rate of unicompartmental knee arthroplasty has been variable, and controversy still surrounds its use. Achieving good functional results from this surgery may require understanding surgical principles, precise operative techniques, and careful patient selection. This paper evaluates clinical results and factors influencing postoperative knee function after unicompartmental knee arthroplasty. The follow-up assessment of 109 knees that underwent unicompartmental knee arthroplasty showed that 90 of 109 knees were classified as excellent or good (82.6%) using the Hospital for Special Surgery knee scoring system. In the excellent group (54 knees), 52% of the postoperative, standing femorotibial angles converged on a range of 170 degrees to 175 degrees with a mean of 174 degrees +/- 4 degrees. The knees with residual flexion contracture after surgery showed poorer clinical results. Therefore, complete elimination of the flexion contracture during surgery is considered mandatory.