Revision arthroplasty with use of a total femur prosthesis.

BACKGROUND: Surgeons performing revision arthroplasties of the hip and knee are confronted with a growing number of patients with extensive loss of bone stock. Implantation of a total femur prosthesis is a possible method of treatment of such patients. The purpose of this study was to assess the functional outcomes and the complications associated with total femur replacements used in revision arthroplasty.

METHODS: We evaluated the results associated with 100 total femur prostheses that had been implanted during revision arthroplasty in 100 consecutive patients without infection. The mean duration of follow-up was five years. The prosthesis was implanted because of a complication of a total hip replacement in seventy-seven patients, because of a complication of a total knee replacement in four, and because of a complication affecting the diaphysis of the femur in nineteen. Thirty-nine patients had sustained a periprosthetic fracture, usually in combination with loosening of the prosthesis, before the revision. The radiographs made at the time of the latest follow-up were evaluated for signs of loosening and material failure. The preoperative and postoperative function of the hip and knee was assessed according to the Enneking score. Five patients were lost to follow-up.

RESULTS: Sixty-five patients (68%) had no complications. Deep infection was found in twelve patients (13%); dislocation, in six (6%); material failure, in three (3%); patellar problems, in two (2%); and peroneal nerve palsy, in one (1%). The mean preoperative Enneking score for hip function was 1.25 points, and it improved to 3.29 points postoperatively. The mean Enneking score for knee function was 2.09 points preoperatively and 3.29 points postoperatively.

CONCLUSIONS: We believe that the total femur prosthesis is a useful implant for patients with extensive bone loss at revision arthroplasty. While the infection rate was high, the overall functional results for both the hip and the knee were rated as better than good with the Enneking classification.