Severe metallosis due to abnormal abrasion of the femoral head in a dual bearing hip prosthesis. A case report.

Abstract

The authors report on a patient with a case of severe metallosis due to an abnormal abrasion of the femoral head. A primary arthroplasty was performed using a dual bearing hip prosthesis with acetabular bone grafting by ceramic screws. At the time of the revision surgery the synovia was black, and an analysis using a scanning electron microscope and scanning electron microscope-electron probe micro-analyzer revealed numerous small particles of small alumina ceramic on the inner surface of the bearing insert of high-density polyethylene. These particles, which came from the broken ceramic screws due to proximal migration of the prosthesis, scraped the femoral head away. A line and area analysis of the black synovia revealed that the synovia contained metal particles of a cobalt-chromium alloy as well as a cobalt ion. The patient's serum showed elevated concentrations of cobalt, chromium, and molybdenum that dramatically reduced 2 months after the revision surgery.