Study of the Mechanical Properties of Bones Under Fracture Healing Conditions with Specific Medical Treatments, Using 4 Point Bending Tests and Ultra-Micro Indentation Techniques

Abstract This paper aims to compare the effectiveness of two medical treatments in healing an induced pseudoarthrosis (bone fracture without direct contact thus driving a callus formation) on the right femurs of Sprague Dawley laboratory rats. To further understand and quantify the mechanical effects of each treatment, the bone mechanical properties were analysed in terms of the following parameters: hardness and elastic modulus using ultra-micro indentation tests, and maximum force, energy absorbed up to maximum force and rigidity using four point bending tests. To assess the effectiveness of the treatments in terms of mechanical performance, the results were compared against a control group and a regular bone fracture (direct contact between broken bone parts without a gap). Both treatments were successful in restoring properties similar to the control group in terms of overall hardness (in both cortical and trabecular bone tissues) and rigidity. However, one of them appears to provide higher values of maximum force, energy absorbed and bone hardness. The results provide information that can be extrapolated to further understand the treatment of human bone fractures in terms of mechanical properties. The data enables the comparison of the outcomes that both treatments have on the biomechanical functioning of bone fractures