INTRAVENOUS BISPHOSPHONATE THERAPY AT THE TIME OF SURGERY ENHANCES NEW BONE FORMATION DURING DISTRACTION OSTEOGENESIS IN IMMATURE RABBITS

Objective: To evaluate the effects of a new potent bisphosphonate on the formation, mineralisation, density, and mechanical properties of bone in distraction osteogenesis. Methods: Thirty immature New Zealand White rabbits had a 10.5 millimetre lengthening of their tibia performed over 2 weeks using an Orthofix M-100 fixator. Ten control rabbits received saline only; 10 received the new bisphosphonate at the time of surgery, and 10 received a second dose at the end of distraction. Bone mineral content (BMC) and density (BMD) measurements were made at two, four and six weeks. Quantitative CT analysis of regenerate, proximal and distal bone, and corresponding segments in the non-operated limb was performed after culling. Mechanical testing was by 4-point bending. Results: Bone mineral accrual was significantly faster in both treatment groups (ANOVA p Conclusion: Bisphosphonate therapy significantly increased new bone formation, bone mineralisation and mechanical properties. Osteoporotic effects were reversed. This effect could have wide ranging implications for many orthopaedic practices