ABSTRACT
BACKGROUND: Strontium ranelate (StR) is an antiosteoporotic agent previously utilized for the enhancement of fracture union. We investigated the effects of StR on fracture healing using a rabbit model. METHODS: Forty adult female rabbits were included in the study and were divided in 2 equal groups, according to StR treatment or untreated controls. All animals were subjected to osteotomy of the ulna, while the contralateral ulna remained intact and served as a control for the biomechanical assessment of fracture healing. Animals in the study group received 600 mg/kg/day of StR orally. All animals received ordinary food. At 2 and 4 weeks, all animals were euthanatized and the osteotomy sites were evaluated for healing through radiological, biomechanical, and histopathological studies. RESULTS: The treatment group presented statistically significant higher callus diameter, total callus area, percentage of fibrous tissue (p < 0.001), vessels/mm2, number of total vessels, and lower osteoclast number/mm2 (p < 0.05) than the control group at 2 weeks. Additionally, the treatment group presented significantly higher percentages of new trabecular bone, vessels/mm2, osteoclast number/mm2, and lower values for callus diameter, as well as total callus area (p < 0.05), than the control group at 4 weeks. At 4 weeks, in the treatment group, force applied (p = 0.003), energy at failure (p = 0.004), and load at failure (p = 0.003) were all significantly higher in the forearm specimens with the osteotomized ulnae compared to those without. Radiological bone union was demonstrated for animals receiving StR at 4 weeks compared with controls (p = 0.045). CONCLUSION: StR appears to enhance fracture healing but further studies are warranted in order to better elucidate the mechanisms and benefits of StR treatment.
