Every year, an increasing number of individuals suffer from osteoporosis, a degenerative bone disease which results in compromised bone mechanical properties. The amplified cost of treatment associated with impaired fracture healing and the increased risk of fracture related morbidity in patients suffering from osteoporosis, make understanding the impact of fracture healing on bone mechanical properties a high priority.
Destructive mechanical testing is by far the most common method used to characterize bone mechanical properties, given that it is the most reliable determinate of bone stiffness. However, the accuracy of bone mechanical properties, derived from mechanical testing, is limited by a variety of factors including assumed idealized cross-sectional geometries. The purpose of this research is to determine if medical-image based bone strength analysis could be used to improve statistical significance between experimental factors when compared to the results of mechanical testing alone.
The present research includes a continuation study of four-point bending tests which compared the time-dependent bone mass, force at failure (Fmax) and stiffness (kbending) of the healing callus to that of the intact bone in wild-type and genetically-modified mice. A Micro-computed tomography (μ-CT) image-based mechanical analysis was performed on the fractured and intact wild-type femurs of the previous study using a homogeneous material model. Increased statistical significance was found between callus and intact limbs in the μ-CT derived properties when compared to Fmax and kbending of the original experiment. Thus, medical-image based mechanical analyses of bone strength enhanced four-point bending test results in a mouse bone fracture model.
Future research includes the application of a heterogeneous material model in order to potentially increase the statistical significance in the mechanical properties derived from mechanical testing coupled with µ-CT image-based mechanical property analysis in the current research.