Yamasaki S et al. (2007) Risedronate reduces postoperative bone resorption after cementless total hip arthroplasty. Osteoporos Int 18: 1009–1015

Periprosthetic bone resorption is a complication of cementless total hip arthroplasty (THA). Part of the stress that would normally be experienced by the femur is borne by the implant, leading to bone remodeling, and this resorption can lead to loosening of the implant. Bisphosphonate therapy has been shown to protect against bone resorption after THA. As no data so far exist on the effect of risedronate in this setting, Yamasaki et al. conducted a randomized, placebo-controlled study of the effect of risedronate on periprosthetic bone resorption after cementless THA.

Participants were randomly allocated to placebo (n = 21) or risedronate (2.5 mg/day; n = 22) for 6 months after undergoing cementless THA. Three patients in the risedronate group withdrew because of dyspepsia. BMD in the proximal femur (which was divided into seven zones) was measured 3 weeks and 6 months postoperatively by dual-energy X-ray absorptiometry. There was no significant difference in BMD between the groups at 3 weeks; these values were used as baseline figures. At 6 months, BMD decrease was significantly less in the risedronate group than in the placebo group in the five most proximal zones; BMD ranged from 79.8% to 91.1% of baseline in the placebo group, and from 88.1% to 100.9% of baseline in the risedronate group. There was no significant difference in BMD loss in the two most distal zones.

The authors conclude that risedronate helps to protect against periprosthetic bone resorption after cementless THA.