Pitt | Swanson Engineering

Degradable Magnesium Alloys as Novel Bone Implants

Among three major classes of biomaterials: metals, ceramics, and polymers, the metals have gained popularity for load-bearing applications due to their high stiffness and mechanical strength, compared to polymers and ceramic materials. Thus, metallic implants based on Ti (Ti6Al4V), Co-Cr alloys, and stainless steel (SS316L) have been used for more than a decade by clinicians for orthopedic reconstruction. However, a strong mismatch between the elastic moduli and tensile strengths of these metals and natural bone causes stress shielding effects resulting in the weakening and consequent fracture of the surrounding bone. In addition, the long-term use of current inert metal implants often requires invasive secondary surgery to prevent the side effects from wear debris causing metallosis and other related foreign body response. Adult patients are likely to undergo secondary removal surgery only in the case of any eventual complication. On the other hand, pediatric patients are highly likely to require secondary surgeries to remove the implants interrupting bone growth. Therefore, the development of biodegradable metal implants to overcome the limitations of current clinical solutions is of high interest in the field of orthopedics and regenerative medicine. Biodegradable Mg alloy based implant devices will resorb in a controlled fashion thus overcoming the limitations of current metallic implants while keeping the advantage of higher stiffness and mechanical strength. Our group over the past 10 years is working to develop various Mg based alloys with improved bio-corrosion resistance and bio-mechanical properties. In addition, various fixation devices have been developed and tested for their local and systemic toxicities.

Degradable Magnesium Alloys as Novel Bone Implants

Bone fixation devices made of Mg alloys (a). Photographs of plate and screws; and (b). Low magnification SEM images of a representative porous bone scaffolds.

 

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