Alternative bearing surfaces: alumina ceramic bearings for total hip arthroplasty

Osteolysis resulting from polyethylene wear debris is one of the most common causes of implant failure in young, active individuals who undergo total hip arthroplasty. Reducing wear may help extend the life of the implant in these patients. Contemporary alumina ceramic/alumina ceramic bearing articulations are harder, scratch resistant, and more hydrophilic than other bearing couples, resulting in reduced wear and reduction of particle load to the surrounding tissue. Therefore, bearings made of alumina ceramic may be a preferable bearing choice for younger, more active patients. To investigate this hypothesis, 495 patients (514 hips), average age 53 years, were enrolled in a prospective, randomized, multicenter study comparing an alumina-on-alumina ceramic bearing to a cobalt-chromium-on-polyethylene bearing control. At an average of 4 years after implantation, no difference in clinical outcome was observed between groups. There were no fractures of the ceramic head or liner, nor were there any revisions caused by the ceramic liner. Another investigational group was added to the study 1 year after enrollment in the original study was closed. The same inclusion/exclusion criteria were used. A total of 194 consecutive patients (209 hips) received an alumina liner that included a thin metal backing designed to allow bearing replacement and ease surgical assembly. At an averagefollow-up of 30 months, no liner or head chips or fractures were observed in this group.