Metal-on-Metal Bearings

Lynne C. Jones, Warren O. Haggard, A. Seth Greenwald

This book addresses the background and significance of the factors potentially influencing the clinical and biological outcomes of metal-on-metal hip implants. Metal-on-metal bearings were introduced and evaluated as an alternative to other bearing couples, particularly metal-on-polyethylene, due to their enhanced wear resistance as determined in laboratory testing. Initially, reports of short-term clinical outcomes were favorable and an increasing number of metal-on-metal prostheses were implanted. Subsequently, isolated case findings describing adverse tissue responses around the articulation became the harbinger of an increasing number of reports describing pseudotumors and other significant lymphocytic-based responses associated with metal-on-metal prostheses. Questions have been raised as to whether this is an implant, design, or patient-specific response. The reasons why some...