The loading rate influences the fracture mechanics of bone. The effect of strain rate on bone tissue was studied. Two sets of dynamic tests were performed, where the impact energy E = 70 J was kept as a constant value. In the first set, the impact velocity of the striker was set to 5.15 m/s, and in the second set of dynamic tests, the impact velocity was set to 7.84 m/s. In each set, four pig femurs were tested, resulting in a total of eight femurs tested. In order to maintain the same impact energy, when testing at a lower velocity, a set of weights (+3 kg) was added to the impactor. The ductility index evaluates the propagation behaviour of brittle versus ductile fracture based on direct force measurements from a force/time diagram.

This study proposes mechanical stress as a common integrative parameter that connects biological bone adaptation with engineering mechanics. In engineering, stress is defined as the internal reactive force per unit area within a loaded body; in clinical practice, its biological consequences can be observed on radiographs, CT, and MRI as callus formation, hypertrophy, or oedema, and perceived by the patient as localised pain. Three-dimensional geometry models were constructed in Autodesk Fusion and Inventor, and stress distributions were visualised using Abaqus finite element analysis. Representative clinical cases (n = 5) were drawn from the radiographic archive of Dubrovnik County Hospital. The analysis showed that regions of elevated stress predicted by finite element models corresponded spatially with areas of callus growth observed on clinical radiographs, and that the presence or absence of stress correlated with subjective pain reports. These findings suggest that stress may serve as a clinically and biomechanically relevant parameter bridging radiographic observation and engineering analysis of bone healing and remodelling.