title: Serum metal ion levels after rotating-hinge knee arthroplasty: comparison between a standard device and a megaprosthesis.
abstract: OBJECTIVE
  The effects of systemic metal ion exposure in patients with implants made of common prosthetic alloys continue to be a matter of concern. The aim of the study was to determine the measurement values of cobalt (Co), chromium (Cr) and molybdenum (Mo) in serum following rotating-hinge knee arthroplasty.
  
  
  METHODS
  Blood was taken from 25 patients [mean follow-up 35 (range nine to 67) months] treated with megaprostheses (n=17) or standard rotating-hinge devices (n=8) and analysed using electrothermal graphite furnace atomic absorption spectrometry (ET-ASS).
  
  
  RESULTS
  Determining the concentrations of metal ions following rotating-hinge knee arthroplasty revealed increments for Co and Cr but not Mo. Metal ion release was significantly higher in patients with megaprostheses compared to a standard rotating-hinge knee device (Co p=0,024; Cr p=0.025).
  
  
  CONCLUSIONS
  The authors believe there might be an additional metal ion release from the surface of the prosthesis and not only from the articulating surfaces because, in cases of rotating-hinge knee prosthesis, there is a metal-on-polyethylene articulation and not a direct metal-on-metal junction. Nevertheless, long-term studies are required to determine adverse effects of Co, Cr and Mo following total hip replacement and total knee arthroplasty.
authors.affiliation: Department of Orthopaedic Surgery, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria. joerg.friesenbichler@medunigraz.at
authors.forename: Joerg
authors.initials: J
authors.lastname: Friesenbichler
authors.forename: Werner
authors.initials: W
authors.lastname: Maurer-Ertl
authors.forename: Patrick
authors.initials: P
authors.lastname: Sadoghi
authors.forename: Thomas
authors.initials: T
authors.lastname: Lovse
authors.forename: Reinhard
authors.initials: R
authors.lastname: Windhager
authors.forename: Andreas
authors.initials: A
authors.lastname: Leithner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D005260:Female; D006801:Humans; D007477:Ions; D007720:Knee Prosthesis; D008297:Male; D008670:Metals / Q000097:blood*; D008875:Middle Aged; D008982:Molybdenum / Q000097:blood; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000009:adverse effects*; D013499:Surface Properties; D055815:Young Adult
chemical_list: D007477:Ions; D008670:Metals; D002857:Chromium; D003035:Cobalt; D008982:Molybdenum