Alendronate in the prevention of collapse of the femoral head in nontraumatic osteonecrosis: A two-year multicenter, prospective, randomized, double-blind, placebo-controlled study

Objective Osteonecrosis is one of the major debilitating skeletal disorders. Most patients with osteonecrosis of the femoral head eventually need surgery, usually total hip arthroplasty (THA), within a few years of onset. Previous studies showed that alendronate has a pharmacologic effect in reducing osteoclast activity and that it significantly reduced the incidence of collapse of the femoral head in the osteonecrotic hip. The purpose of this study was to determine the cumulative incidence of THA in patients with osteonecrosis of the femoral head and the time-to-event after treatment with alendronate versus placebo during the study period. Methods A 2-year multicenter, prospective, randomized, double-blind study was performed. From June 2005 to December 2006, 64 patients were enrolled and randomly assigned to the alendronate or placebo group. In patients with bilateral hip osteonecrosis who met the inclusion criteria, both hips were counted in the analyses. Five patients were excluded from the analysis because they did not comply with any of the study regimens. Seven patients were ineligible because they were not diagnosed as having stage IIC or stage IIIC disease according to the University of Pennsylvania system. Thus, a total of 52 patients (65 hips) were assessed in this study. Disease progression was evaluated by radiography and magnetic resonance imaging (MRI). The Harris Hip Score and the Short Form 36 health survey were used to rate hip function and quality of life, respectively. Results There was no significant difference in radiographic and MRI data between the 2 study groups. Four of 32 hips in the alendronate treatment group underwent THA, while 5 of 33 hips in the placebo group had THA (P = 0.837). No differences were noted in disease progression, Harris Hip Scores, or Short Form 36 scores between the 2 groups. Conclusion Alendronate has no obvious effect on preventing the necessity for THA, reducing disease progression, or improving life quality.