The Interface Between Degradable Mg and Tissue

Magnesium (Mg) and its alloys degrade under physiological conditions, which makes them interesting implant materials, especially for osteosynthesis and cardiovascular applications. However, how strong is the connection between the implant, the degradation layer, and the surrounding tissue, namely bone? Considering that microscopically the interface can be separated into the border between the metal and the degradation layer, the degradation layer itself, and the border between the degradation layer and the biological environment, it is not obvious that this zone with total thickness of several tens of microns is sufficient to keep an implant in place. However, biomechanical approaches such as push-out tests have shown that a degraded Mg pin is surprisingly well connected with the bone irrespective of the fragile appearance of the degradation layer. This paper provides an overview of what is known about the interface between degrading Mg implants, cells, and bone tissue.