title: Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties: a literature overview.
abstract: OBJECTIVE
  Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties.
  
  
  METHODS
  Studies were searched for in the Medline database, Embase, and the Cochrane Database of Systematic Reviews. Highest mean or median ion concentrations of Cr and Co after a minimum of 1 year of follow-up were extracted and grouped according to sample- and articulation type, and average values were calculated.
  
  
  RESULTS
  43 studies were included and 16 different MoM implants were identified. For the different types of bearings, average ion concentrations and range were calculated from the mean or median ion concentration. The average Cr concentration ranged between 0.5 and 2.5 μg/L in blood and between 0.8 and 5.1 μg/L in serum. For Co, the range was 0.7-3.4 μg/L in blood and 0.3-7.5 μg/L in serum.
  
  
  CONCLUSIONS
  When the average blood ion concentrations calculated for the different implants, together with the concentrations measured in the individual studies, were compared with the upper acceptable limit for Cr and Co in blood, no clear pattern was recognized. Furthermore, we were unable to detect any clear difference in ion concentrations between different types of implants (THA and resurfacing).
authors.affiliation: Departments of Orthopaedic Surgery, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark. christopherjantzen@gmail.com
authors.forename: Christopher
authors.initials: C
authors.lastname: Jantzen
authors.forename: Henrik L
authors.initials: HL
authors.lastname: Jørgensen
authors.forename: Benn R
authors.initials: BR
authors.lastname: Duus
authors.forename: Sune L
authors.initials: SL
authors.lastname: Sporring
authors.forename: Jes B
authors.initials: JB
authors.lastname: Lauritzen
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D002857:Chromium / Q000097:blood*; D003035:Cobalt / Q000097:blood*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008670:Metals
chemical_list: D008670:Metals; D002857:Chromium; D003035:Cobalt