title: High prevalence of adverse reactions to metal debris in small-headed ASR™ hips.
abstract: BACKGROUND
  There has been increasing concern of metal-on-metal (MOM) hip replacements regarding adverse reactions to metal debris. Information regarding prevalence and risk factors for these adverse reactions is scarce.
  
  
  OBJECTIVE
  The primary purposes of our study were to determine (1) the prevalence of adverse reactions to metal debris among patients who received small-headed (< 50 mm) Articular Surface Replacement (ASR™) prostheses in hip resurfacing procedures or the ASR™ XL prostheses during THAs at our institution, and (2) the risk factors for adverse reactions to metal debris and if they are different in hip resurfacing replacements compared with THAs?
  
  
  METHODS
  Small-headed ASR™ prostheses were used in 482 operations (424 patients) at our institution. After the recall of ASR™ prostheses, we established a systematic screening program to find patients with adverse reactions to metal debris. At a mean of 4.9 years (range, 0.2-8.1 years) postoperatively, 379 patients (435 hips) attended a screening program, which consisted of clinical evaluation, whole blood cobalt and chromium measurements, and cross-sectional imaging.
  
  
  RESULTS
  At followup, 162 hips (34%) have been revised. The majority (85%) were revised owing to causes related to adverse reactions to metal debris. The 7-year survivorship was 51% for the ASR™ hip replacement cohort and 38% for the ASR™ XL THA cohort, respectively. Reduced cup coverage was an independent risk factor for adverse reactions to metal debris in both cohorts. High preoperative ROM, use of the Corail(®) stem, and female gender were associated with an increased risk of adverse reactions to metal debris only in patients undergoing THA.
  
  
  CONCLUSIONS
  Adverse reactions to metal debris are common with small-headed ASR™ prostheses. Risk factors for these adverse reactions differ between hip resurfacing procedures and THAs. Our results suggest a more complicated failure mechanism in THAs than in hip resurfacing procedures.
authors: Coxa Hospital for Joint Replacement, P.O. Box 652, 33101, Tampere, Finland.
authors: Aleksi
authors: A
authors: Reito
authors: Timo
authors: T
authors: Puolakka
authors: Petra
authors: P
authors: Elo
authors: Jorma
authors: J
authors: Pajamäki
authors: Antti
authors: A
authors: Eskelinen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006615:Hip / Q000601:surgery; D006621:Hip Joint / Q000601:surgery; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008670:Metals / Q000097:blood; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D015995:Prevalence; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D008670:Metals; D002857:Chromium; D003035:Cobalt
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