title: Effects of photo-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine on physical properties of cross-linked polyethylene in artificial hip joints.
abstract: Osteolysis caused by wear particles from polyethylene in the artificial hip joints is a serious issue. We have used photo-induced radical graft polymerization to graft 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer onto the surface of cross-linked polyethylene (CLPE-g-MPC) in order to reduce friction and wear at the bearing surface of the joint. The physical and mechanical properties of CLPE and CLPE-g-MPC were not significantly different, expect that the friction coefficient of untreated CLPE cups was 0.0075, compared with 0.0009 for CLPE-g-MPC cup, an 88% reduction. After 3.0 x 10(6) cycles in the hip joint simulator test, we could not observe any wear of CLPE-g-MPC cups. We concluded that the advantage of photo-induced radical graft polymerization technique was that the grafted MPC polymer gave a high lubricity only on the surface and has no effect on the bulk properties of the CLPE substrate.
authors.affiliation: Research and Development Corporate Division, Japan Medical Materials Corporation, Uemura Nissei Bldg 9F, 3-3-31 Miyahara, Osaka, Japan. kyomotom@jmmc.jp
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kyomoto
authors.forename: Toru
authors.initials: T
authors.lastname: Moro
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Konno
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takadama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takatori
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
authors.forename: Noboru
authors.initials: N
authors.lastname: Yamawaki
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008689:Methacrylates / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D046529:Microscopy, Electron, Transmission; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D010777:Photochemistry; D020959:Polyethylene / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D011109:Polymethacrylic Acids; D011475:Prosthesis Failure; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis; D014965:X-Rays
chemical_list: D001672:Biocompatible Materials; D008689:Methacrylates; D011109:Polymethacrylic Acids; C115766:poly(2-methacryloyloxyethyl-phosphorylcholine); D010767:Phosphorylcholine; D020959:Polyethylene