PubMed2006
BACKGROUND: Recent studies have indicated that the rate of successful long-term outcome after primary total hip arthroplasty for patients with osteonecrosis may be improved with the use of later-generation porous-coated prostheses (biologic ingrowth fixation) and cement techniques (cement fixation). Less is known about the long-term outcome after revision arthroplasty in the same patient population. The purpose of this study was to characterize the clinical and radiographic outcomes of revision total hip arthroplasty in patients with osteonecrosis. METHODS: We evaluated thirty-four osteonecrotic hips in thirty patients who had undergone revision of a femoral component of a prior total hip arthroplasty. There were nineteen men (twenty-two hips) and eleven women (twelve hips) with a mean age of forty-six years. Thirty one of thirty-four hips were implanted without cement. The cementless prostheses were of different stem lengths, but thirty of thirty-one were proximally porous coated. The mean duration of follow-up was 8.2 years. Prerevision radiographs were used to determine the degree of femoral bone loss according to the classification system of Della Valle and Paprosky. The need for revision was analyzed for correlation to known risk factors for osteonecrosis, age and gender of the patient, and degree of prerevision femoral deficiency. A clinical and radiographic evaluation of outcome was performed. RESULTS: This was the first revision for twenty-seven hips, the second for five hips, and the third for two hips. Preoperatively, the defects included four Type I, nine Type II, fifteen Type IIIA, two Type IIIB, one Type IV, and three unknown. The femoral component was rerevised in twelve of the thirty-four hips. One of the failures was the only fully porous-coated stem that was implanted. One of the three cemented implants failed, as compared with eleven of the thirty-one noncemented implants. Survival rates were 90.9% at five years, 54.8% at ten years, 54.8% at fifteen years, and 27.4% at twenty years. With the small sample size, no relationship could be identified with regard to frequency of re-revision and defects, associated risk factors, patient age, or gender. CONCLUSIONS: There was a high failure rate of revised, uncemented, proximally coated femoral components in patients with osteonecrosis of the femoral head at the time of the intermediate-term follow-up. The cause of failure could not be correlated with patient age, gender, risk factors for osteonecrosis, or femoral bone stock. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.