The Oxford II medial unicompartmental knee arthroplasty: an independent 10-year survival study.

Unicompartmental knee arthroplasty (UKA) is being used increasingly. We report the outcome of a series of 48 Oxford II meniscal bearing UKAs carried out for osteoarthritis of the medial compartment (38 knees in 32 patients) and for spontaneous avascular necrosis of the medial femoral condyle (10 knees in 10 patients). Using the endpoint of revision for any cause, the outcome for every knee was established. Ten knees have been revised (20.8%). At ten years there were 215 knees still at risk and the cumulative survival rate was 77.7% (95% CI: 56.8 to 90.2). Our study reveals a higher failure rate than previous reports on this prosthesis. The technique of implantation of the Oxford knee is demanding; the learning curve is thus long and could explain, at least partially, our moderate results.