Patellofemoral arthroplasty with a custom-fit femoral prosthesis

Abstract

We reviewed the outcomes of a series of patellar arthroplasty operations with custom-fit femoral prostheses to examine the effectiveness of this procedure in relieving pain and restoring function in the knee. Twenty-two patellofemoral arthroplasty operations were performed in 21 patients (mean age, 48.6 years) at 2 institutions between 1994 and 2002. All patients had advanced patellofemoral arthritis and had undergone an average of 2.5 previous patellofemoral operations. The prosthesis, consisting of a custom-fit chrome cobalt trochlear component and an all-polyethylene patellar button, was implanted in a procedure designed to minimize bone resection. Patients later underwent three-view radiography of the knee to confirm that the prosthesis was positioned correctly. One patient required revision of an undersized patellar button 18 months postoperatively, and 2 other patients had postoperative arthrofibrosis necessitating arthroscopic debridement. No patient required revision of the trochlear component, and no loosening or migration of any component has been found since the first procedure was performed. However, the polyethylene patellar button has worn in 3 patients, and the patella broke in 1 patient. An average of 60 months postoperatively, patients used the Western Ontario and McMaster Universities Osteoarthritis Index to rate their preoperative and present joint pain, stiffness, and function. Patients' mean overall ratings (potential range, 24-96) were significantly lower for their present symptoms (28.4) than for their preoperative symptoms (63.4). Mean scores on each subscale also decreased: from 13.0 to 5.5 for pain, from 5.4 to 2.4 for stiffness, and from 45.0 to 20.6 for function. We conclude that, in carefully selected patients, patellofemoral arthroplasty with a custom-fit prosthesis is a viable surgical treatment for isolated patellofemoral arthritis.