Patellofemoral resurfacing arthroplasty in the active patient

Middle-aged patients with advanced isolated patellofemoral (PF) chondrosis/arthrosis want to remain active. Unfortunately, most of these individuals are not good candidates for realignment alone with or without cartilage restoration. Historically, these patients might have been considered candidates for patellectomy, but long-term follow-up has pointed out the morbidity of that procedure, which makes it an unacceptable option for these patients. Some arthroplasty proponents consider total knee replacement (TKA) as the “gold standard” for treating isolated PF arthritis. However, TKA changes the kinematics of the knee and often limits knee flexion, leaving many patients unable to remain as active as their partial knee replacement counterparts; moreover, TKA carries the risk of loosening for which the only solution remains a major revision. While patellofemoral resurfacing arthroplasty (PFA) has been available as long as TKA, it has a checkered past as a treatment for isolated PF arthritis. Fortunately, with newer generation implants and the recognition of the surgical technique’s unique features, many patients have very satisfactory outcomes. In those satisfied patients, activity recommendations must be based both on what the knee can do kinematically and on what the PFA will tolerate from a wear and loosening standpoint. With current material and implant methods, patients must be cautioned to minimize component overload, which may result in polyethylene (when present) wear and loosening; however, activities that maintain cardiopulmonary fitness and general conditioning can generally be allowed.