Computational study of the interaction between degradation of biodegradable magnesium implants and bone remodelling

Abstract

Biodegradable magnesium implants are increasingly applied to promising orthopaedic fixation devices due to obvious advantages over conventional permanent implants. However, potential risks of environment assisted corrosion failures during their service in human body have not been systematically studied [1], which leads to a limitation of the extensive applications of the magnesium implants. In addition, the influence of the degradation process of magnesium implants on the bone remodelling after surgery is also a critical factor. Therefore, a modelling approach is required to understand their interactions with the physiological environment and improve the design of biodegradable magnesium implants with respect to the healing efficiency of fractured bones. In the present work, three-dimensional computer simulations are conducted for a fractured femur fixed by the bone plate and screws to investigate the service behaviour of magnesium implants and their interaction with the bone healing process. A mechano-regulatory model based on the biphasic stimuli is used to simulate tissue differentiation and bone remodelling of the fractured femur. A corrosion damage model is used to describe the complex degradation process of mechanical integrity of magnesium implants under physiological loadings. The simulation results are consistent with the experimental observation. The present modelling approach provides an efficient tool in the design and the performance evaluation of biodegradable magnesium implants.