The Effect of Zoledronic Acid on the Intrinsic Material Properties of Healing Bone: an Indentation Study

BACKGROUND:Bisphosphonates are commonly used for the treatment of osteoporosis and have recently been shown to increase bone mineral parameters and strength in endochondral fracture repair. There is concern, however, that BPs may negatively affect bone material properties.METHODS:Nanoindentation was performed on femoral fracture samples of rats that had undergone closed fracture healing for six weeks to determine hardness and elastic modulus. The rats had received either intravenous saline or a single intravenous dose of zoledronic acid at zero, one or two weeks post fracture (n = 3 per group).FINDINGS:The mean elastic modulus and hardness of mineralised tissue in control calluses were mean 16.4 GPa (S.D. 2.3) and mean 0.65 GPa(S.D. 0.1), respectively. There was no significant change in these parameters with zoledronic acid treatment.INTERPRETATION:The results from this preliminary data suggest that single dose zoledronic acid treatment in fracture healing may not adversely affect the intrinsic properties of callus bone tissue. Single dose bisphosphonate may be a viable treatment for augmenting fracture repair without negatively affecting the material properties.