Total hip arthroplasty in patients with underlying fibrous dysplasia.

Fibrous dysplasia is a developmental anomaly of bone formation that accounts for approximately 7% of benign bone tumors. It exists in a monostotic or polyostotic form, commonly occurs in the proximal femur, and may require total hip arthroplasty (THA) for its management in a select group of patients. The results of THA in patients with this disorder is not known. Of the 27,543 primary THAs performed at our institution between 1969 and 2001, 10 were in patients with fibrous dysplasia (prevalence of 0.04%). Two other patients (2 hips) with the same diagnoses were referred after a failed primary THA. The study group comprised 7 men and 4 women (1 bilateral) with an average age at primary THA of 44 years (range, 23-66 years). Four patients had the monostotic form and 7 patients had the polyostotic form. A cemented stem was used in 7 hips and cementless stem in the rest (N=12). Average follow-up was 15.7 years (range, 2-30 years). Seven hips in 6 patients were revised for loosening of components at an average of 12.5 years, and 2 of these were re-revised for the same reason. Loosening of a cementless femoral component led to early revision in 3 hips. The surgical outcomes for patients with monostotic was better than those with polyostotic disease. Long-term fixation of the femoral component is of concern in patients with fibrous dysplasia. Total hip arthroplasty provided these patients with long-lasting pain relief and function despite the higher rate of complications at the time of surgery.