Effect of risedronate on bone metabolism after total hip arthroplasty: a prospective randomised study.

Aseptic loosening due to bone remodeling and osteolysis is the main reason for revision hip arthroplasty. At present, there is no established prophylaxis for this complication. On the other hand, it has been demonstrated that bisphosphonates prevent bone loss around total hip arthroplasties (THA). The aim of this study was to assess the efficacy of oral bisphosphonate risedronate for the prevention of deleterious changes in bone metabolism after hip replacement. Twenty-four patients who underwent THA were randomised to two treatment arms: 35 mg risedronate once weekly for 6 months (12 patients) and no treatment for controls (12 patients). Markers of bone turnover bone specific alkaline phosphatase, serum osteocalcin and urinary deoxypiridinoline were evaluated at baseline, third and sixth postoperative month. Dual energy X-ray absorptiometry of the nonsurgical hip was performed preoperatively and at 6 months postoperatively. There were no significant differences in clinical or radiographic findings between the two groups at either 3 or 6 months. In the two groups, all biochemical marker responses at the third postoperative month were suppressed compared with baseline. Values of bone resorption marker urinary deoxypiridinoline increased significantly at six months in the control group. For the 10 risedronate patients with bone densitometry bone mineral density reached 1.01% increase at 6 months. Administration of oral risedronate led to a significant reduction in bone metabolism at 6 months after hip replacement. This therapeutic strategy may improve the results and longevity of total hip arthroplasty. The beneficial effect of risedronate should be confirmed in further studies including larger number of patients and longer follow-up. The action of risedronate could prevent aseptic loosening of hip arthroplasty by preserving periprosthetic bone stock.