Degradation of metal hip implants

Regardless of their type, implanted metal devices will interact with the biological environment; thus, mechanical wear, corrosion, and their combined actions (i.e., tribocorrosion) are inevitable. The implications of these mechanisms have been observed in vivo and linked with early failure and revision of many types of hip implants. This chapter provides a basic overview of the principles of tribology, corrosion, tribocorrosion, and the major sources of material loss from metal prostheses. This is followed by a discussion of the methods used to quantify implant wear and map metal deposits in periprosthetic and systemic tissue, and the role of the degradation mechanism on the characteristics of the resultant debris.