Long-term results with the first patellofemoral prosthesis.

UNLABELLED: We retrospectively reviewed 70 patients, representing 79 knees, who had isolated patellofemoral arthroplasty between 1975 and 1991 using the Richards II and III implants. Seventy-five percent of the prostheses were still functioning at a minimum of 6 and average followup of 10 years after implantation. The main cause of failure was secondary femorotibial osteoarthritic deterioration (8 knees). Only two complications of a mechanical nature related to the implant have been observed. Surgical revisions have not presented any particular difficulties. The main indication for this type of implant is advanced patellofemoral osteoarthritis secondary to a constitutional trochlear dysplasia occurring in a correctly aligned knee for which no other therapeutic procedure allows the same type of result to be achieved. LEVEL OF EVIDENCE: Therapeutic Study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.