Unicompartmental knee arthroplasty: functional recovery and radiographic results with a minimally invasive technique

We prospectively evaluated 100 consecutive unicompartmental knee arthroplasties, performed in minimally invasive quadriceps-sparing fashion, for medial compartment osteoarthritis in patients aged 46 to 79 years, with anteromedial tibial wear, less than 10 degrees of flexion contracture, correctable varus not exceeding 15 degrees , and an intact anterior cruciate ligament. We aimed to determine (1) early functional outcome and (2) radiographic limb alignment and component placement. Mean incision length was 7.2 cm, hospital stay 2.1 days, and blood loss 240 ml. Flexion at 3 months was between 120 degrees and 155 degrees (mean, 139 degrees ). Among the patients, 80% could flex beyond 130 degrees , and 91% could sit cross-legged, kneel, and get up easily from the floor. The mean hip-knee-ankle axis was 177 degrees . Ninety-five percent of femoral components were centered on the tibial component. Tibial component slope was restored in 91%.