Numerical simulation of the tissue differentiation and corrosion process of biodegradable magnesium implants during bone fracture healing

Biodegradable magnesium implants are considered as promising fixation devices in the orthopaedic application to replace the conventional implants with unexpected properties. Extensive applications of magnesium implants are still limited by the uncontrolled corrosion rate in the body fluid and their interactions with the tissue differentiation during bone healing. In addition, the evaluation of the mechanical integrity of implants is essential for stabilisation fractured bones. Therefore, a modelling approach is required to investigate the effect of the degradation process of implants on the healing efficiency of fractured bones. In the present work, a mechano-regulatory model based on the biphasic stimuli is used to simulate tissue differentiation of fractured tibia. A corrosion damage model is extended by employing a nonlocal integral formulation to describe the pitting corrosion of magnesium implants. The physiological loadings are taken into account in 3D simulations. The simulation results are consistent with the experimental observation in the literature. The present modelling approach provides an efficient tool in the design and the performance evaluation of biodegradable magnesium implants.