Outcome of patellofemoral arthroplasty, determinants for success.

The primary aim of this study is to document whether patellofemoral arthroplasty is a good treatment option for patellofemoral osteoarthritis and to identify prognostic outcome factors. Secondary aim is to investigate the influence of preoperative tibiofemoral osteoarthritis on the clinical outcome. From 2004 to 2010, 37 Avon patellofemoral prostheses were implanted in 32 patients. Clinical outcome was evaluated with five questionnaires: KOOS, Kujala, VAS, OKS and Satisfaction Score. Radiographs were analyzed using the IWANO and Kellgren-Lawrence classification. To identify determinants of outcome, subgroups were examined according to sex, age, diagnosis, BMI and prior surgery. Patellofemoral arthroplasty is a valuable treatment for patellofemoral osteoarthritis. After prosthesis placement, KOOS, Kujala, VAS and OKS improved significantly (all p < 0.001). Patients with prior patellofemoral surgery were clinically worse (p < 0.05). Patients with preoperative Kellgren-Lawrence grade 2 tibiofemoral osteoarthritis had a significantly worse outcome compared to grade 1 (p < 0.05). Further research is necessary to determine whether patellofemoral arthroplasty is indicated in these patients.