title: Mixing and matching in ceramic-on-metal hip arthroplasty: an in-vitro hip simulator study.
abstract: The clinical success of second-generation metal-on-metal hip replacement and the good tribological performance of alumina ceramic revived an interest in hip articulation as a solution to reduce wear. This study was aimed at characterizing the wear behaviour of new hybrid ceramic-on-metal bearings. In particular, this study investigated the wear behaviour of ceramic-on-metal hip components (three different diameters configurations: 28, 32 and 36 mm), not specifically proposed to be coupled, in order to compare them with ceramic-on-ceramic, which is considered to be the gold standard for wear resistance. For this purpose, the weight loss over a standard wear simulation was monitored. Moreover, scanning electronic microscope observations were used to verify if any carbides removal, for the metallic components, triggered wears debris production promoting abrasive third-body wear. After five million cycles, our results showed significantly greater wear-in ceramic-on-metal compared with ceramic-on-ceramic, and significant greater wear for the 32-mm diameter compared with the 36-mm one. Our findings showed an increase in wear for the proposed hybrid specimens with respect to that of the ceramic-on-ceramic ones confirming that even in the case of ceramic-on-metal bearings, mixing and matching could not prove effective wear behaviour, not even comparable with that of the ceramic-on-ceramic gold standard. Wear patterns and roundness tolerances certainly discourage the coupling of components not specifically intended to be coupled. Unsuitable geometrical conformity could, in fact, result in a poor dynamic behaviour and lead to clinical failure.
authors.affiliation: Laboratorio di Tecnologia Medica, Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy. affatato@tecno.ior.it
authors.forename: Saverio
authors.initials: S
authors.lastname: Affatato
authors.forename: Michele
authors.initials: M
authors.lastname: Spinelli
authors.forename: Stefano
authors.initials: S
authors.lastname: Squarzoni
authors.forename: Francesco
authors.initials: F
authors.lastname: Traina
authors.forename: Aldo
authors.initials: A
authors.lastname: Toni
mesh_terms: D002516:Ceramics; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods; D006622:Hip Prosthesis; D006801:Humans; D008670:Metals
chemical_list: D008670:Metals