Effect of Strontium Ranelate on Fracture Healing in the Osteoporotic Rats

The aim of this study was to evaluate the effect of strontium ranelate (SrR) on fracture healing in the osteoporotic rat model. Forty female Sprague Dawley rats aged 3 months were enrolled in the study. Osteoporosis was induced by bilateral ovariectomy and subsequent daily heparin injection started 1 week after surgery and lasted for 4 weeks. Osteoporosis was confirmed by a reduction of bone mineral density (BMD). Twenty of the osteoporotic rats were assigned to the SrR group and the remaining 20 to the control group. An open right tibial midshaft transverse fracture was created and then an intramedullary fixation was performed. SrR group was treated by 450 mg/kg/day SrR per oral. Six weeks after surgical induction of fracture, all animals were sacrificed. One animal from each group died after ovariectomy. Two tibiae from the control group failed to unite. SrR-treated group showed higher mechanical strength and fracture stiffness when compared to the control group (p = 0.006, p = 0.001, respectively). SrR-treated group had mature woven bone or predominantly woven bone compared with osteoporotic control group (p = 0.038). SrR-treated group's callus maturity was significantly higher than control group (p = 0.001). SrR is associated with better fracture healing in the osteoporotic rat model. (C) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 138-142, 2011