The significance of metal staining on alumina femoral heads in total hip arthroplasty.

Metallic transfer to alumina can occur intraoperatively and while reducing a dislocated total hip, when the femoral head contacts the rim of the metal acetabular shell. To see if metal discoloration is associated with changes to the alumina, we examined 14 metal-stained alumina femoral heads retrieved from ceramic-on-ceramic articulations using electron microscopy and noncontact profilometry. Metal staining was associated with surface damage to alumina on the femoral heads removed from unstable total hips. The surface roughness of metal-stained alumina heads was significantly greater than that of unused alumina heads. Alumina femoral heads should be protected against contact with the metal cup during total hip implantation. Dislocations in ceramic-on-ceramic total hips should be addressed early because of possible damage to the surface.