Midterm clinical results of the Autocentric II patellofemoral prosthesis.

We studied the outcome of patellofemoral arthroplasties using the Autocentric prosthesis implanted in our clinic between 1994 and 2004. New insight on indications and contraindications motivated us to find risk factors in the failure of this prosthesis. Twenty-four patients had surgery for patellofemoral arthritis not responding to exhaustive nonoperative measures. The mean age at the time of patellofemoral arthroplasty (PFA) was 63.4 (SD 11.3, range 38-81) years with a mean follow-up of 4.8 (SD 2.9, range 2-11) years. Additional interventions were necessary in 21 knees during follow-up in our population, and seven knees required total knee arthroplasty (TKA) mainly due to progressive tibiofemoral osteoarthritis and maltracking of the patella. The patient outcomes and quality of life scores showed disappointing results, even after revision to TKA. This retrospective analysis underlines the importance of strict indications for patellofemoral arthroplasty and, in particular, of contraindications.