Investigation of Biodegradation Behavior of an Mg-1Ca Alloy during <i>In Vivo</i> Testing

Abstract

In case of an orthopedic implant, it would be ideal that resorption to occur by biodegradation and bone remodeling. The main advantage of using resorbable orthopedic implants is eliminating the need for a new surgical procedure. The use of pure magnesium for orthopedic implants shows some drawbacks, which need to be considered and evaluated by in vitro and in vivo assays. One of the main problems encountered when pure Mg is used as biodegradable implant is represented by a high corrosion rate, faster than the rate of bone formation. The aim of this study is testing and evaluation of Mg-1Ca alloy from biocompatibility in vivo point of view. The purpose of in vivo test was to demonstrate good biocompatibility and lack of local and systemic toxicity of implants made by Mg-1Ca alloy. The study was conducted by implanting Mg-1Ca alloy parallelepiped shaped implants in the tibia of rabbits. In our tests related to Mg-1Ca alloy in vivo evaluation, there were no pathological increases in blood levels of Mg and Ca, or other elements, showing that it has no adversely affect to their metabolism. Also it shows a good bone integration, newly formed bone being adherent to the implant surface, with no tissue interposed between it and the bone. In conclusion, magnesium alloy Mg-1Ca represents a promising solution in orthopedic surgery, proving to be safe, with a high degree of biocompatibility and without toxic effects during in vivo testing.

Magnesium-Based Alloys Used in Orthopedic Surgery

“…Osteogenesis consists of new bone tissues development in order to repair a fractured bone [ 78 ]. This process is necessary for a material to work as a temporary implant.…”

Treatment of Knee Osteochondral Fractures

“…Bioabsorbable metallic implants made from zinc (Zn), iron (Fe), or magnesium (Mg) alloys have been developed in the last few years [ 46 , 47 ]. Unfortunately, the low zinc mechanical strength and toxicity of the degradation products and the magnetic nature of iron and iron oxide degradation results led to additional research regarding Zn- and Fe-based alloys until a suitable solution can be developed.…”

“…From a mechanical properties point of view, the Mg screws exhibit higher pull-out forces than in the case of biocompatible polymers [ 53 ]. In the presence of body fluids, Mg alloys degrade through corrosion [ 47 , 54 ]. Secondary products such as oxides, hydroxides, or hydrogen species were noticed, but they were not associated with a clinical important side effect [ 55 ].…”