Patellofemoral arthroplasty. A 2- to 18-year followup study.

Sixteen patellofemoral arthroplasties in 13 patients were evaluated to assess long term results. Preoperative diagnoses included 10 patients with primary patellofemoral osteoarthritis, 2 patients with posttraumatic osteoarthritis secondary to patellar fracture, and 1 patient with recurrent patellar subluxation/dislocation. The average patient age at surgery was 64 years (range, 42-84 years) and average length of followup was 5.8 years (range, 2-18 years). A modified Hungerford and Kenna knee rating system was used for evaluation, and serial radiographs were assessed for mechanical failure of the components or progressive arthritic deterioration of the knee compartments. Fourteen (88%) of 16 patellofemoral arthroplasties in 11 (85%) of 13 patients were rated as excellent or good. One revision was required at 18 months for persistent patellar malalignment and subluxation, and now is rated as excellent at more than 16 years of followup, modifying the final results to 94% successful patellofemoral arthroplasties in 92% of the study patients. No mechanical failure has occurred, and no patient has required patellofemoral arthroplasty conversion to total knee arthroplasty. Patellofemoral arthroplasty is a viable surgical option for selected patients with isolated patellofemoral arthritis when additional factors, such as extraarticular disease and multicompartment arthritic degeneration, are considered.