Patellofemoral arthroplasty.

Patellofemoral arthroplasty remains controversial, primarily due to the high failure rates reported with early implants. Several case series have been published over the years, which describe the results with various first- and second-generation implants. The purpose of this work was to summarize results published up to now and identify common themes for implants, surgical techniques, and indications. First-generation resurfacing implants had relatively high failure rates in the medium term. Second-generation implants, with femoral cuts based on TKA designs, have yielded more promising medium-term results. The surgical indications are quite specific and must be chosen carefully to minimize poor results. Short-term complications are generally related to patellar maltracking, while long-term complications are generally related to progression of osteoarthritis in the tibiofemoral joint. Implant loosening and polyethylene wear are rare. Overall, recent improvements in implant design and surgical techniques have resulted in better short- and medium-term results. But more work is required to assess the long-term outcomes of modern implant designs.