Ceramic-on-Metal Bearing in Total Hip Arthroplasty—Was It So Bad? A Narrative Review and a Critical Analysis of the Literature

Hip replacement has significantly improved the quality of life of patients with symptomatic hip osteoarthritis. Metal-on-metal (MoM) bearings have been used with conventional total hip re-placement (THR) for several decades with promising results from early applications. Wear and corrosion of these implants may lead to a release of metal products into surrounding tissue and body fluids. From the 1980s onwards, the search for increasingly better coupling materials with low levels of wear led to the rise of hard-on-hard couplings such as ceramic-on-ceramic (CoC). The latter is currently the coupling with the longest known duration and with a wear rate close to zero. MoM coupling has been for a long time the most significative alternative, but systemic and local complications linked to the release of chromium and cobalt ions, determine the withdrawn from the market. One other alternative proposed over the time has been Ceramic-on-Metal (CoM) bearing. Preliminary results have been described as favourable, but due to the failures of metal on metal it has been withdrawn from the market, without causing significant clinical complications. In this narrative review, we analysed risks and benefits associated with the implantation of hybrid hard-on-hard bearings, such as CoM.