No adverse effects of clodronate on fracture healing in rats

Clodronate was administered daily 28 days before and after an experimental tibial fracture in 35 male rats, and the effect on fracture healing and pos ttraumatic bone loss was studied. 5 groups were tested. The clodronate/clod ronate group received clodronate in daily doses of In mg/kg body weight for 28 days before being subjected to a standardized fracture of the right tib ia, and during the fracture healing period of 28 days. The clodronate/salin e group received clodronate before fracture and saline during the healing p eriod. The saline/clodronate group received saline before and clodronate af ter fracture. The saline/saline group received saline only, while the contr ol group served as unfractured, untreated controls. After 28 days of fractu re healing, the tibias were evaluated with dual energy x-ray absorptiometry , and tested mechanically in a 3-point ventral bending test. Bone mineral c ontent and bone mineral density were approximately 30% higher in the groups receiving clodronate during the experiment, compared to the untreated grou ps. The weight and cross-sectional area of the fracture callus were equal i n all groups. Whether clodronate was administered before the fracture, afte r the fracture or both, did not affect the bone mineral. Ultimate bending m oment, energy absorption, stiffness and deflection were not significantly d ifferent between the groups. Our findings suggest that clodronate Increases bone mineral both when given before and after a tibial shaft fracture, wit hout affecting fracture healing at 28 days.