Patellofemoral arthroplasty.

Patellofemoral arthroplasty can be an effective intermediate treatment for the patient with isolated arthritis of the anterior compartment of the knee. In the absence of patellar malalignment, results are optimized when an implant with sound geometric features is used, the prosthesis is appropriately aligned, and the soft tissues are balanced. Although previous prosthesis designs resulted in a relatively high prevalence of failure because of patellofemoral maltracking, patellofemoral catching, and anterior knee pain, newer prosthesis designs show promise in reducing the prevalence of patellofemoral dysfunction. Progressive tibiofemoral cartilage degeneration is another so-called failure mechanism; such progressive degeneration underscores the importance of restricting the procedure to patients who do not have tibiofemoral chondromalacia. Because long-term failure as a result of tibiofemoral degeneration may occur in approximately 25% of patients, patellofemoral arthroplasty may be considered an intermediate procedure for select patients with patellofemoral arthritis.