The effects of irradiation on bone fracture healing: Can it promote mineralization at low doses?

This experimental study investigated the hypothesis that low dose irradiation can enhance fracture healing and mineralization. Standardized transverse femur fractures were created and intramedullary fixed with open technique to forty young adult, male Sprague-Dawley rats and randomized to RT (treatment with 1 Gy) and C (controls, sham treatment) groups. At third and sixth week after fracture, high resolution Bone Mineral Density (BMD) analysis, bone scintigraphy and radiographic examination with a mammography device were performed and rats were sacrificed for histopathological examinations. Statistically significant differences were found at sixth week; as BMD index was found to be higher in RT group (p = 0.006) and BMD value was found lower in the non-fracture region of the irradiated femurs (p = 0.005). No statistically significant differences were found between groups for other parameters. The results showed increased mineralization at the fracture site only when compared with irrradiated non-fractured bone region, which cannot be regarded as a basis for clinical practice. However, when applications like heterotopic ossification prophylaxis are considered, the issue remains to be solved by molecular techniques, especially for doses between 1 and 5 Gy.