CoCrMo metal-on-metal hip replacements.

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Tribology

Background:

• Metal-on-metal hip replacements (CoCrMo) saw increased use but declined due to biocompatibility concerns.
• Wear and corrosion debris from these implants raise significant concerns about local tissue response.
• The in vivo and in vitro interactions between CoCrMo bearings and the human body remain poorly understood.

Purpose of the Study:

• To review recent advancements in understanding the wear and corrosion of metal-on-metal hip replacements.
• To discuss key factors influencing implant performance, including materials, deformation, and tribocorrosion.
• To highlight open questions and potential adverse health effects associated with implant wear products.

Main Methods:

• Review of in vivo and in vitro studies on CoCrMo hip implant wear and corrosion.
• Discussion of material properties, mechanical deformation, and electrochemical corrosion processes.
• Analysis of wear-assisted corrosion mechanisms and the characterization of wear products.

Main Results:

• CoCrMo metal-on-metal hip implants generate wear and corrosion debris.
• These debris particles can elicit adverse local tissue reactions.
• The complex chemistry of corrosion and tribochemical reactions requires further investigation.

Conclusions:

• Further research is needed to fully elucidate the chemistry of corrosion and tribochemical reactions in CoCrMo hip implants.
• Understanding these interactions is vital for improving the safety and longevity of artificial hip joints.
• Designing advanced materials for human implants requires similar attention to performance as seen in automotive applications.