Mg bone implant: Features, developments and perspectives

Mg and its alloys have been identified as promising bone implant materials owing to their natural degradability, good biocompatibility and favorable mechanical properties. Nevertheless, the too fast degradation rate usually results in a premature disintegration of mechanical integrity and local hydrogen accumulation, which limit their clinical bone repair application. In this work, the current research status regarding Mg bone implants was systematically reviewed. The relevant strategies to enhance the corrosion resistance, including purification, alloying treatment, surface coating and Mg-based metal matrix composite, are comprehensively discussed. The fabricating techniques for Mg bone implants are also presented. Particularly, laser additive manufacturing can fabricate customized shape and complex porous structure basing on its unique additive manufacturing concept. More importantly, it can achieve rapid heating and cooling due to the characteristics of high laser energy density and good controllability, thereby regulating the microstructure and performance. Furthermore, the current challenges and future research perspectives are put forward. This work aims to offer some meaningful guidelines for researchers on the future study of Mg bone implants.