Clinical Results of Ceramic on Ceramic Systems 87 Alternative Bearing Surfaces: Alumina Ceramic Bearings for Total

Osteolysis resulting fronn polyethylene wear debris is one of the nnost common causes of implant failure in young, active individuals who undergo total hip arthroplasty. Reducing wear may help extend implant life in younger, more active patients. Contemporary alumina ceramic/alumina ceramic bearing articulations are harder, are scratch resistant, and ore more hydrophilic than other bearing couples. This results 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, a total of 495 patients (514 hips), average age of 53 years, were enrolled in a prospective, randomized, multicenter study comparing an alumina-on-olumina ceramic bearing to a cobalt-chrome-on-polyethylene bearing control. At an average of four years post-implantation, no difference in clinical outcome was observed between groups. There were no ceramic head or liner fractures in this group, nor were there any revisions due to the ceramic liner. Another investigational group was added to the study one 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 operative assembly. At an average follow-up of 30 months, no liner or head chips or fractures were obsen/ed in this group