Abstract
A standard is defined as something established by authority, custom, or general consent. Clearly that does not exist for ceramic on ceramic total hip replacement. A better question is: Is there any indication for a ceramic on ceramic total hip. The answer to that question should when possible be based on clinical outcome data including the value added (or not) with this more expansive technology.
Ceramic on ceramic has been popularised based on its low wear. Is this clinically relevant? Probably not, based on currently available data. Both metal on highly crosslinked polyethylene and ceramic on highly crosslinked polyethylene have very low clinically documented wear rates with excellent outcomes in multiple studies. In addition, ceramic on ceramic bearings are more sensitive to implant position. Whereas polyethylene may tolerated edge loading and impingement, ceramic bearings are less likely to do so. Dislocation remains one of if not the top reason for early revision. Even with newer ceramics, there are still less options to fine tune hip stability with ceramic on ceramic bearing surfaces. When looking at the overall, risk of revision, Bozic et al concluded that hard bearings provided no benefit in terms of risk reduction of revision. Considering their higher cost, they questioned the use of these products especially in the 65 and older age group.
Looking at the Australian Registry, the cumulative percent revision for ceramic-ceramic THA was 5.7% at 11 years compared to 5.1% for metal on crosslinked poly. The hazard ratio (adjusted for age and gender) was 1.09 in favor of ceramic on poly and the difference was highly significant (p=0.012). When one take into account the increased cost of ceramic on ceramic bearings, it is hard to make a case for ceramic on ceramic bearings.
Any use of ceramic on ceramic bearings would have to be based on the hypothesis that in the long run in young active patients they may provide an advantage. This is a hypothesis with no data to support it currently.
