Advances in Biodegradable Orthopaedic Implants: Optimizing Magnesium Alloy Corrosion Resistance for Enhanced Bone Repair

Biomaterials revolutionize medicine, enabling cutting-edge applications like anchoring devices, substitutes, and advanced surgical equipment. Bio-implants are intended to sustain a damaged biological structure, substitute for an absent biological structure, or augment an extant biological structure. Utilized bioimplants can be classified as ceramics, metals, or polymers. Among the different types of implant materials, many are designed to remain permanently in the body, despite their temporary function. Biodegradable implants are particularly advantageous because they dissolve and are absorbed during the healing process. This invention spares patients from additional surgeries, reduces immobility, and cuts medical costs. In particular, biodegradable implants have improved orthopaedic surgical results, reduced complications, and promoted natural bone repair. With its outstanding biocompatibility and biodegradability, magnesium (Mg) stands out as a promising biodegradable orthopaedic implant. Its mechanical properties mimic natural bone, which helps to prevent stress shielding and enhances osteoblast attachment. Despite these advantages, the rapid degradation of magnesium poses challenges for sustained bone growth. Therefore, improving magnesium's corrosion resistance is crucial for its effective use in bone production. Mg-based metallic glasses, which are stronger, more elastic, and highly corrosion-resistant than crystalline materials, are being considered as biodegradable implant materials. The chemical homogeneousness, absence of secondary phases, and lack of grain boundaries in Mg metallic glasses reduce the formation of Mg2+ ions, H2 bubbles, and OH− ions. Successful implantation of tacks, screws, and other orthopaedic implants needs Mg metallic glasses to be a few centimetres thick. However, maximum-diameter glasses require a high glass-forming alloy. Thus, for Mg alloys to readily become glassy and larger in diameter, the composition of these glasses must be understood. This study explores current research, strategies, and technological advancements in biodegradable orthopaedic implants, with a particular focus on the performance of Mg. Furthermore, it provides an in-depth analysis of magnesium alloys' corrosion behaviour and discusses solutions to reduce their corrosion rate.