Free vascularized fibular grafting for the treatment of postcollapse osteonecrosis of the femoral head.

BACKGROUND

Osteonecrosis of the femoral head, a disease primarily affecting young adults, is often associated with collapse of the articular surface and subsequent arthrosis. Free vascularized fibular grafting has been reported to be successful for patients with early stages of osteonecrosis, but little is known about its efficacy after the femoral head has collapsed.

METHODS

We retrospectively reviewed the results in a consecutive series of 188 patients (224 hips) who had undergone free vascularized fibular grafting, between 1989 and 1999, for the treatment of osteonecrosis of the hip that had led to collapse of the femoral head but not to arthrosis. The average duration of follow-up was 4.3 years (range, two to twelve years). We defined conversion to total hip arthroplasty as the failure end point, and we analyzed the contribution, to failure, of the size of the lesion, amount of preoperative collapse of the femoral head, etiology of the osteonecrosis, age of the patient, and bilaterality of the lesion. We used the Harris hip score to evaluate clinical status preoperatively and at the time of the most recent follow-up.

RESULTS

The overall rate of survival was 67.4% for the hips followed for a minimum of two years and 64.5% for those followed for a minimum of five years. The mean preoperative Harris hip score was 54.5 points, and it increased to 81 points for the patients in whom the surgery succeeded; 63% of the patients in that group had a good or excellent result. There was a significant relationship between the outcome of the grafting procedure and the etiology of the osteonecrosis (p = 0.017). Patients in whom the osteonecrosis was idiopathic, associated with alcohol abuse, or posttraumatic fared worse than did those with other causes, including steroid use. Survival of the joint was not significantly related to the size of the femoral head lesion, but there was an increased relative risk of conversion to total hip arthroplasty with increasing lesion size and amount of collapse. Neither patient age nor bilaterality significantly affected outcome.

CONCLUSIONS

Patients with postcollapse, predegenerative osteonecrosis of the femoral head appear to benefit from free vascularized fibular grafting, with good overall survival of the joint and significant improvement in the Harris hip score. The results of this femoral head-preserving procedure in patients with postcollapse osteonecrosis are superior to those of core decompression and nonoperative treatment, as reported in the literature. Patients with larger lesions and certain diagnoses, such as idiopathic and alcohol-related osteonecrosis, have worse outcomes.