Advances of biodegradable magnesium-based implants for orthopaedics

Abstract

Stainless steel, titanium alloys, cobalt-chromium alloys and other metal materials are the most widely used orthopaedic implants. However, there are still some problems in clinical application, including a mechanical mismatch between metal and bone, inflammation and secondary operation. As a new generation of medical metal materials, magnesium (Mg) and its alloys have attracted much attention due to their excellent biodegradability. Biodegradable Mg-based metals have good mechanical and osteogenic properties, and are expected to become implant materials to treat challenging orthopaedic diseases. However, the rapid corrosion rate is still one of the main challenges restricting its clinical application. Alloy and surface modification are effective methods to control the corrosion rate of Mg alloys. This paper reviews the mechanical and biological properties of biodegradable Mg alloys and the problems when they are applied clinically, emphasizing the latest progress of Mg-based metals in alloying and surface modification. The status of the application of Mg-based implants in orthopaedics are also described.