Serum Ion Levels after Ceramic-on-Ceramic and Metal-on-Metal Total Hip Arthroplasty: 8-Year Minimum Follow-up

Alternative bearing surface for total hip arthoplasty, such as metal-on-metal and ceramic-on-ceramic, offer the potential to reduce mechanical wear and osteolysis. In the short and medium term, the second generation of metal-on-metal bearings demonstrated high systemic metal ion levels. whereas ceramic-on-cerainic hearings showed the lowest ones. We aimed to verify whether the long-term ion release in metal-on-metal subjects was still relevant at a median 10-year follow-up, and whether a fretting process at the modular junctions occurred in ceramic-on-ceramic patients and induced an ion dissemination. Serum levels were measured in 32 patients with alumina-on-occured implants (group A), in 16 subjects with metal-on-metal implants (group B), and in 47 healthy subjects (group C). Group B results were compared with medium-term findings. Cobalt and chromium levels were significantly higher in metal-on-metal implants than in ceramic-on-cerainic ones and controls. Nevertheless, ion levels showed a tendency to decrease in comparison with medium-term content. In ceramic-on-ceramic implants, ion values were not significantly different from controls. Both in groups A and 13, aluminium and titanium release were not significantly different from controls. In conclusion, negligible serum metal ion content was revealed in ceramic-on-cerainic patients. On the contrary, due to the higher ion release, metal-on-metal coupling must be prudently considered, especially in young patients, in order to obtain definitive conclusions. (c) 2008 Orthopaedic Research Society. Published by Wiley Periodicals. Inc. J Orthop Res 26:1569-1576, 2008