title: Metal ion levels in ceramic-on-ceramic THR with cobalt-chrome modular necks: analysis of cobalt and chromium serum levels in 23 healthy hip patients.
abstract: BACKGROUND
  Modular necks in total hip replacement (THR) can be a source of metal ion release.
  
  
  METHODS
  We measured the level of cobalt (Co) and chromium (Cr) ions in the serum of 23 healthy volunteers with a well-functioning ceramic-on-ceramic THR of a particular design, containing a cobalt-chrome (Co-Cr) stem and a Co-Cr modular neck.
  
  
  RESULTS
  Average Co in serum was 1,71 µg/l; median Co was 1.50 µg/l. No patient had Co levels higher than 3.70 µg/l. Average Cr level was 0.49 µg/l; in all but one patient Cr was below the detection limit (<0.50 µg/l). Co was higher for varus necks compared to all other subtypes: 2.14 µg/l vs 1.58 µg/l (p<0.05). The same system with Titanium modular necks shows lower Co serum levels: 1.26 µg/l (p<0.01 ). In conclusion, the hybrid THR Profemur Xm® - Procotyle L® with a Co-Cr modular neck on a Co-Cr stem design shows very low Cr ion serum levels in a randomly selected group of well-functioning hip patients.
  
  
  CONCLUSIONS
  Co ion serum levels are low, but significantly higher for 8° varus necks, and Co levels are significantly higher than values of this system with a Titanium modular neck.
authors: Department of Orthopaedic and General Surgery, Jan Yperman Hospital, Ypres - Belgium.
authors: Jan F A
authors: JF
authors: Somers
authors: Department of Orthopaedic and General Surgery, Jan Yperman Hospital, Ypres - Belgium.
authors: Lieven
authors: L
authors: Dedrye
authors: Department of Orthopaedic Surgery, Catholic University of Leuven, Leuven - Belgium.
authors: Sofie
authors: S
authors: Goeminne
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D015415:Biomarkers / Q000097:blood; D002516:Ceramics / Q000737:chemistry*; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000097:blood* / Q000000981:diagnostic imaging / Q000601:surgery*; D011237:Predictive Value of Tests; D011475:Prosthesis Failure; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment
chemical_list: D015415:Biomarkers; D002857:Chromium; D003035:Cobalt