title: Metal ion levels in ceramic-on-ceramic THR with modular necks: analysis of cobalt and chromium serum levels in 30 healthy hip patients.
abstract: BACKGROUND
  Modular necks in total hip replacement (THR) can be a source of metal ion release. There are no data to date on the level of cobalt and chromium ions in the serum of patients with a cobalt-chrome stem and a titanium modular neck.
  
  
  METHODS
  Serum ion levels were measured in healthy volunteers with a well-functioning ceramic-on-ceramic THR.
  
  
  RESULTS
  Average cobalt in serum was 1.21 µg/l for unilateral THR and 2.2 µg/l for bilateral THR. No patient had cobalt levels higher than 2.4 µg/l. No patient had measurable chromium levels. There were no differences in cobalt levels for hips with short necks versus hips with long necks.
  
  
  CONCLUSIONS
  The hybrid THR Profemur® Xm - Procotyl® L with a titanium modular neck on a cobalt-chrome stem design shows no signs of abnormal toxic ion levels (cobalt or chromium) in a randomly selected group of well-functioning hip patients.
authors.affiliation: Department of Orthopaedics, Jan Yperman Hospital, Ypres - Belgium.
authors.forename: Jan F A
authors.initials: JF
authors.lastname: Somers
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D002516:Ceramics; D002857:Chromium / Q000097:blood*; D002858:Chromium Alloys / Q000737:chemistry*; D003035:Cobalt / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D007477:Ions / Q000097:blood; D008297:Male; D008875:Middle Aged; D061214:Patient Safety; D011446:Prospective Studies; D011474:Prosthesis Design / Q000379:methods*; D012016:Reference Values
chemical_list: D002858:Chromium Alloys; D007477:Ions; D002857:Chromium; D003035:Cobalt