Obesity, young age, patellofemoral disease, and anterior knee pain: identifying the unicondylar arthroplasty patient in the United States.

Standard surgical criteria for unicondylar knee arthroplasty exclude patients who weigh >82 kg (187 lbs), patients aged <60 years, and patients with more than minimal erosive changes in the patellofemoral articulation, indicated clinically by anterior knee pain. In April 2004, the US Food and Drug Administration approved the Oxford phase 3 unicondylar prosthesis for implantation during unicompartmental knee arthroplasty. Since this broader indication was adopted, the implant has proven to be a bone- and ligament- conservative yet long-lasting intervention for anteromedial arthritis of the knee. The purpose of this study is to investigate the early outcomes of unicompartmental medial knee arthroplasty using the Oxford prosthesis in US patients who do not meet the standard inclusion criteria. Specifically, the current study investigates the impact of obesity, young age, patellofemoral arthritis, and isolated medial knee pain on the early outcomes of this device. In this large series of 318 unicompartmental knee arthroplasties performed in 270 patients, these standard preoperative contraindications had no influence on the successful outcome of the procedure using the Oxford phase 3 device.