title: The wear pattern in metal-on-metal hip prostheses.
abstract: The accumulated data suggest that there is a strong correlation between polyethylene wear and osteolysis, which ultimately leads to prosthetic loosening. Second-generation metal-on-metal prostheses have been introduced, with an eye toward resolving this wear-induced osteolysis problem. The metal particles and ions are biologically active and can affect the cell homeostasis. Thus, defining the wear pattern and ratio of a given metal-on-metal prosthesis system is desirable. An early high-wear or run-in phase followed by a low-wear phase or steady state has been suggested for metal-on-metal hip prostheses. The aim of this study was to define the wear pattern of metal-on-metal bearings. The prosthesis systems were tested in a joint simulator. An early accelerated wear phase transformed to a slower wear phase after 700,000 cycles. The run-in and steady-state wear rates for combined head and liner averaged 2.22 mm(3)/Mc and 1.0 mm(3)/ million cycles, respectively. The metal-on-metal prosthesis featured a biphasic wear trend with the wear ratio in run in being more than twofold higher than the steady-state phase.
authors.affiliation: Department of Orthopaedic Surgery, Karolinska University Hospital, S-171 76 Stockholm, Sweden. Lucas.Anissian@ks.se
authors.forename: H L
authors.initials: HL
authors.lastname: Anissian
authors.forename: A
authors.initials: A
authors.lastname: Stark
authors.forename: V
authors.initials: V
authors.lastname: Good
authors.forename: H
authors.initials: H
authors.lastname: Dahlstrand
authors.forename: I C
authors.initials: IC
authors.lastname: Clarke
mesh_terms: D001672:Biocompatible Materials; D002858:Chromium Alloys; D019544:Equipment Failure Analysis; D006622:Hip Prosthesis; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010014:Osteolysis / Q000209:etiology; D011475:Prosthesis Failure; D013314:Stress, Mechanical
chemical_list: D001672:Biocompatible Materials; D002858:Chromium Alloys