RESUMO
BACKGROUND: Approximately 10% of patients with osteoarthritis (OA) of the knee have unicompartmental OA confined to the patellofemoral joint (PFJ). The main surgical options are total knee replacement (TKR) and PFJ replacement (PFJR). PFJR has a number of advantages over TKR, including being less invasive, preserving the unaffected parts of the knee, allowing faster recovery and better range of motion and function. We report our prospective mid-term results of the Avon PFJR for established isolated PFJ arthritis in 61 consecutive procedures. METHODS: Sixty-one Avon PFJRs were performed in 57 patients. The outcome measures were the new Oxford knee score (OKS), Hungerford and Kenna score (HKS), and Crosby Insall knee scores. Only patients with severe isolated PFJ OA were included. The diagnosis was based on a combination of clinical, radiological and, where available, arthroscopic findings. RESULTS: Mean follow-up was 5.09 years (range, 12 to 124 years). There were 2 revisions in the first 5 years. The median HKS score was 80 (interquartile range, 70 to 95) and the mean OKS was 31.8 (+/- standard deviation, 8.7) at 5 years. These were significantly better (p < 0.001) than the preoperative scores. CONCLUSIONS: The Avon prosthesis gives good functional outcomes in the medium term and survives well. Our data support other studies in the literature and is the largest independent prospective study to date.