Patellofemoral arthroplasty.

Patellofemoral arthroplasty is an effective treatment for isolated arthritis of the anterior compartment of the knee. The best results are obtained when there is no patellar malalignment, the prosthesis is appropriately aligned, the soft tissues are balanced, and the implant has sound design features. The prevalence of patellofemoral dysfunction and failure caused by patellar maltracking and catching has been considerably reduced by the use of contemporary implant designs rather than earlier implant designs. Progressive tibiofemoral cartilage degeneration is the predominant failure mechanism; this factor underscores the importance of restricting the procedure to patients who do not have tibiofemoral chondromalacia or arthritis. Newer techniques that combine patellofemoral arthroplasty with autologous osteochondral transplantation or unicompartmental arthroplasty appear to be effective for patients with associated tibiofemoral chondromalacia.