This study investigates the mechanical behavior of femur bones under loading conditions, focusing on the transition from elastic to plastic deformation and eventual fracture. The force–displacement curves reveal distinct phases of deformation, with an initial linear relationship indicating elastic behavior, followed by deviation from linearity marking the onset of plastic deformation. Fracture occurs beyond a critical load, leading to a sharp drop in the force–displacement curve. The maximum fracture force varies among specimens and is influenced by bone geometry, size, cross-sectional area, and cortical thickness. Post-failure analysis highlights additional insights into fracture mechanics and bone material toughness. Reinforcing bones with screws enhances their strength, which is evident in the higher fracture forces observed in force–displacement diagrams. Fixation procedures following fractures further increase bone strength. Comparing specimens with and without strengthening underscores the effectiveness of reinforcement methods in improving bone mechanical properties. After analyzing the results, it is evident that femur bones with reinforcement can withstand greater loads, and they can also absorb higher impact energies while remaining in the elastic deformation range and without suffering permanent plastic damage. This study provides valuable insights into bone biomechanics and the efficacy of reinforcement techniques in enhancing bone strength and fracture resistance.

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.

Bone is a complex tissue composed of inorganic, organic, and cellular components. Far from being inert, it is a metabolically active, dynamic structure that undergoes continuous remodeling throughout life. Most high-resolution imaging techniques are currently limited to ex vivo research due to radiation exposure, sample size restrictions, and long acquisition times. High-resolution computed tomography (HR-CT) and magnetic resonance imaging (HR-MR) can be performed in vivo but have been used primarily for validating diagnostic methods and evaluating osteoporosis treatments. A significant challenge in bone research lies in accurately classifying bone quality. Biomechanical studies on cadaveric material are needed to correlate clinically accessible parameters such as bone mineral density (BMD) with more precise histological and three-dimensional high-resolution imaging data. This study presents experimental results on postmortem porcine femurs, aiming to compare the mechanical response of bone under different impact velocities. The working hypothesis is that loading rate influences fracture mechanics: at lower velocities, fractures are expected to be ductile, while higher velocities are expected to produce brittle or even comminuted fractures.

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.