title: Serum metal ion levels after second-generation metal-on-metal total hip arthroplasty.
abstract: BACKGROUND
  Metal-on-metal bearings for total hip arthroplasty are increasing in popularity. However, metal ion toxicity, metal hypersensitivity, and metal carcinogenicity are the causes concern for patients with metal-on-metal hip replacement. We investigated serum levels of cobalt and chromium ions in patients with successfully implanted second-generation metal-on-metal total hip arthroplasty (THA) using PINNACLE-A (DePuy, Warsaw, IN, USA).
  
  
  METHODS
  Thirty-three patients underwent primary cementless THA with the use of a 36-mm femoral head PINNACLE-A with a metal-on-metal articulation. Blood samples were taken preoperatively, at 3 months, and at 1 year, and levels of cobalt and chromium were determined.
  
  
  RESULTS
  At 3 months, levels of both cobalt and chromium had increased significantly compared with preoperative levels. There were no significant differences between levels of either metal at 3 months and 1 year.
  
  
  CONCLUSIONS
  Patients with metal-on-metal THA had higher circulating levels of metal ions than before arthroplasty at 3 months, with no additional significant increases at 1 year in this study.
authors.affiliation: Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Imanishi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sudo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D002857:Chromium / Q000097:blood*; D003035:Cobalt / Q000097:blood*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D013997:Time Factors
chemical_list: D002857:Chromium; D003035:Cobalt