title: Observation of retrieved ceramic-on-ceramic articular surface: a case of revised total hip arthroplasty due to failure of the support ring.
abstract: We report the case of a 63-year-old woman who required revision surgery for ceramic-on-ceramic total hip arthroplasty (THA) due to failure of the support ring. We retrieved the ceramic cup and head, observed it macroscopically and measured it to determine its shape condition (sphere diameter, sphericity, and circularity) and surface condition (surface roughness by scanning electronic microscopy). Although abrasion was not found at the sliding surface of either the cup or head, it was observed at the edges of the cup and at one part of the head. We point out the risk of the edge contact and conclude the possibility of micro-motion between the cup and the head during walking or loading in vivo, and that contact had taken place at such parts.
authors.affiliation: Department of Orthopedic Surgery, Tokyo Metropolitan Ohtsuka Hospital, 2-8-1 Minamiohtsuka, Toshima-ku, Tokyo, 170-8476, Japan. mibe-o@ohtsuka-hospital.toshima.tokyo.jp
authors.forename: Junya
authors.initials: J
authors.lastname: Mibe
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Imakiire