Denosumab prevented periprosthetic bone resorption better than risedronate after total hip arthroplasty

Periprosthetic fracture caused by periprosthetic bone loss is an important concern in total hip arthroplasty (THA). Denosumab has been approved for postmenopausal women with osteoporosis who are at high risk of fracture. In this randomized controlled trial, we compared the effects of denosumab and risedronate on periprosthetic bone mineral density (BMD) after THA.

The current study analyzed 108 patients who were scheduled to have THA. For 2 years, the patients were randomly assigned to the following two treatment groups: denosumab (60 mg subcutaneously every 6 months) or risedronate (17.5 mg oral weekly). The BMD changes in all Gruen zones and bone turnover markers were measured at the 5^th postoperative day (baseline) and 6, 12, 18, and 24 months postoperatively.

The mean BMD in zones 1, 2, 6, and 7 was significantly higher with denosumab all administration at all postoperative time points compared to the risedronate group. The mean percentage changes in the BMD in these zones from baseline to 24 months postoperatively were + 11.9, + 2.9, + 8.1, and + 5.9% with denosumab group and - 9.6% -3.6, - 2.3, and - 19.2% with risedronate, respectively. The osteoclastic marker, tartrate-resistant acid phosphatase-5b (TRACP-5b), was significantly lower in the denosumab group compared to the risedronate group by 2 months.

Denosumab is more effective in preventing periprosthetic bone resorption than risedronate in the proximal femur. It also increased BMD around the stem implant following THA.