title: Effect of head size on wear properties of metal-on-metal bearings of hip prostheses, and comparison with wear properties of metal-on-polyethylene bearings using hip simulator.
abstract: The effects of articular head size on the wear losses of the metal insert and articular head for a metal-on-metal bearing were examined using a hip simulator manufactured to satisfy ISO 14242-1. The wear properties of metal-on-metal and metal-on-polyethylene bearings were also compared under the same conditions. The total wear losses of the metal insert and articular head decreased with increasing diameter of the metal insert in the range from 28 to 44mm. The total wear loss was greater for a diameter of 48mm than for a diameter of 44mm. When the articular metal insert diameter was smaller than 44mm, the wear loss was reduced because the contact surface pressure increased with increasing metal insert diameter. However, the increase in wear loss observed for the 48-mm-diameter insert might have been due to the considerable increase in the rotation moment with increasing insert diameter. The tendency of decreasing contact pressure calculated using the Hertzian contact stress equation nearly conformed to the change in wear loss. On the other hand, the wear loss of an artificial hip joint consisting of a cross-linked ultrahigh-molecular-weight polyethylene insert (UHMWPE) and a Co-Cr-Mo articular head was small.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-1 Higashi 1-chome, Tsukuba, Ibaraki 305-8566, Japan. Electronic address: y-okazaki@aist.go.jp.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Okazaki
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D019245:Compressive Strength; D019544:Equipment Failure Analysis / Q000295:instrumentation / Q000379:methods*; D017276:Friction; D006621:Hip Joint / Q000503:physiopathology* / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D061825:Metal-on-Metal Joint Prostheses; D011095:Polyethylenes / Q000737:chemistry*; D011474:Prosthesis Design; D013314:Stress, Mechanical; D013499:Surface Properties; D014800:Vitallium / Q000737:chemistry*; D016474:Weight-Bearing
chemical_list: D001672:Biocompatible Materials; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D014800:Vitallium
keywords: Artificial hip joint; Contact pressure; Hip simulator; Metal-on-metal bearing; Metal-on-polyethylene bearing; Wear property