Table 5.

The key disadvantages of Mg (Radha and Sreekanth 2017)

Drawbacks	Details
Low elastic modulus	Lower Mg elastic modulus may be useful in terms of stress shielding, but any implant must be engineered to withstand its load without distortion
Rapid degradation	Mg implants are designed to disintegrate fully, but at a slower rate than bone remodelling. Normal body components (e.g. Zn, Ca and Mn) can, however, be poisonous if the release rate is too great and the amounts are not dealt with effectively (e.g. excess Mg through the kidneys, hydrogen gas through the soft tissues). To prevent the use of harmful alloying elements and provide an adequate release rate for other elements, including those that are naturally occurring, a fully biocompatible Mg alloy is necessary
High hydrogen evolution	The emitted H2 gas accumulates at a rapid pace in the surrounding soft tissues. H2 bubbles may cause necrosis of surrounding tissue by delaying healing at the surgical site. Hydrogen evolution rates of 0.01 mL/cm2/day have been documented for several Mg alloys containing Zn, Al and Mn