A Physical Examination of Orthopaedic Implants and Adjacent Tissue

Abstract

This paper reports a metallurgical study of five metal-on-metal total hip replacements removed from patients because of varying degrees of loss of bone substance and/or proven sensitivity to Ni and Cr. Evidence of corrosion of the Co-Cr-Mo-C alloy used to fabricate the prostheses was found. It is suggested that the products of this corrosion may alter the balance of bone formation/resorption to produce a loss of bone substance. An unusual tissue response which included rod-like particles (1–2 μm long × 0.2 pm in cross section), of possible immunological origin, was seen on examination of the articulating surface of one of the prostheses by scanning electron microscopy.

Key Words:

• hip arthroplasty
• bone calcification
• corrosion
• immunology
• metallurgy
• metal sensitivity