Unicompartmental knee arthroplasty: indications, techniques, and results.

Unicompartmental knee arthroplasty (UKA) was introduced in the early 1970s but did not receive substantial support because total knee arthroplasty was flourishing. In the early 1990s, interest in UKA increased with the introduction of a minimally invasive surgical approach. It is important that the indications for this demanding but achievable surgical technique be strictly observed. The extension and flexion gaps for UKA can be addressed in a similar fashion to total knee arthroplasty and should be equalized. The femoral and tibial components must be properly sized so that the surfaces are well covered without overhang or impingement. UKA results at 10- to 15-year follow-ups are encouraging and are similar to many reported results of total knee arthroplasty.