Outcomes of MAKOplasty Patellofemoral Arthroplasty in Younger Active Patients

Inclusion Criteria: * Arthroscopically demonstrated localized and isolated full-thickness articular cartilage lesions (Grade 2B or 3A-B as defined by Noyes \& Stabler9) on the patellofemoral joint. * Lesion is symptomatic as defined by pain, swelling, locking, or catching that affects daily activities. * Patient provides informed consent. * Patient agrees to comply with postoperative rehabilitation program. Exclusion Criteria: * Obesity (body mass index greater than 35). * Arthroscopically demonstrated full-thickness articular cartilage lesions (Grade 2B or 3A-B) in the other compartments of the knee. * Uncorrected varus or valgus malalignment * Uncorrected knee joint instability * Knee arthrofibrosis * Patient unwilling to comply with postoperative rehabilitation * Significant muscular atrophy and weakness that does not respond to rehabilitation * History of alcohol or drug abuse within 3 years of the operation. * Disabling or widespread osteoarthritis or other joint disease in any other joint. * Presence of a significant connective tissue disease, autoimmune disease, HIV-positive, or immune deficiency syndrome. * Any contraindications to surgery or other medical disorder that in the opinion of the principal investigator would interfere with the conduct of the study.