title: Cobalt and chromium levels in blood and urine following hip resurfacing arthroplasty with the Conserve Plus implant.
abstract: BACKGROUND
  The purpose of the present study was to determine cobalt and chromium ion levels in the blood and urine of patients in whom a modern-generation metal-on-metal hip resurfacing device had been implanted.
  
  
  METHODS
  A total of ninety-seven patients with a Conserve Plus metal-on-metal hip resurfacing implant were followed prospectively for two years. Cobalt and chromium levels in erythrocytes, serum, and urine were measured preoperatively as well as three, six, twelve, and twenty-four months postoperatively.
  
  
  RESULTS
  The median serum cobalt and chromium ion levels were 1.04 μg/L (range, 0.31 to 7.42 μg/L) and 2.00 μg/L (range, 0.28 to 10.49 μg/L), respectively, at one year after surgery and 1.08 μg/L (range, 0.44 to 7.13 μg/L) and 1.64 μg/L (range, 0.47 to 10.95 μg/L), respectively, at two years after surgery. The corresponding mean levels (and standard deviations) of serum cobalt and chromium were 1.68 ± 1.66 μg/L and 2.70 ± 2.22 μg/L, respectively, at one year after surgery and 1.79 ± 1.66 μg/L and 2.70 ± 2.37 μg/L, respectively, at two years after surgery.
  
  
  CONCLUSIONS
  These levels compare favorably with other published ion results for metal-on-metal hip resurfacing and replacement implants. No pseudotumors or other adverse soft-tissue reactions were encountered in our study population. Further research is needed to determine the clinical importance of increased cobalt and chromium ion levels in serum and urine following metal-on-metal hip resurfacing.
authors.affiliation: Division of Orthopedics, The Ottawa Hospital-General Campus, Room W1650, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada. pkim@ottawahospital.on.ca
authors.forename: Paul R
authors.initials: PR
authors.lastname: Kim
authors.forename: Paul E
authors.initials: PE
authors.lastname: Beaulé
authors.forename: Michael
authors.initials: M
authors.lastname: Dunbar
authors.forename: Joshua K L
authors.initials: JK
authors.lastname: Lee
authors.forename: Nicholas
authors.initials: N
authors.lastname: Birkett
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Turner
authors.forename: Nagarajkumar
authors.initials: N
authors.lastname: Yenugadhati
authors.forename: Vic
authors.initials: V
authors.lastname: Armstrong
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
mesh_terms: D000293:Adolescent; D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D002857:Chromium / Q000097:blood* / Q000652:urine*; D003035:Cobalt / Q000097:blood* / Q000652:urine*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D018709:Statistics, Nonparametric
chemical_list: D002857:Chromium; D003035:Cobalt