title: Outcomes of the Recalled Articular Surface Replacement Metal-on-Metal Hip Implant System: A Systematic Review.
abstract: The aim of this review was to synthesize the main findings of clinical studies that have evaluated outcomes of the articular surface replacement (ASR) Hip System.
  
  
  
  We performed a systematic literature search to identify all articles published between January 2008 and June 2015 that included ASR hip resurfacing arthroplasty (ASR HRA) or ASR total hip arthroplasty (ASR XL THA) outcomes according to the PRISMA statement.
  
  
  
  A total of 56 studies were assessed. The prevalence of adverse local tissue reactions (ALTRs) and revision rates were found to be high. ALTR prevalence varied from 12.5% to 69% (mean, 33.5%). Mean revision rate for any reason at 4-year to 7-year follow-up was 13.8% (range, 5.6%-31%) for ASR HRA and 14.5% (range, 0%-37%) for ASR XL THA. Femoral head size <53 mm was found to correlate with higher blood metal ion levels. Femoral head size >44 mm was not associated with higher ALTR prevalence or revision rates in ASR XL THA. High blood metal ion levels (>7 μg/L Co, >7 μg/L Cr) were associated with higher failure rates and bearing-related complications. The role of cup positioning was found to be controversial.
  
  
  
  ALTR prevalence and failure rates were high. High blood metal ion levels were a risk factor for ALTR and failure. Surprisingly, the role of cup positioning and large femoral head size in ASR XL THA were controversial. These findings should be considered in the clinical follow-up and risk stratification of patients with the ASR Hip System.
authors.affiliation: Department of Orthopedics and Traumatology, Turku University Hospital Turku, Finland.
authors.forename: Inari
authors.initials: I
authors.lastname: Laaksonen
authors.affiliation: Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA.
authors.forename: Gabrielle S
authors.initials: GS
authors.lastname: Donahue
authors.affiliation: Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA; Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA.
authors.forename: Rami
authors.initials: R
authors.lastname: Madanat
authors.affiliation: Department of Orthopedics and Traumatology, Turku University Hospital Turku, Finland.
authors.forename: Keijo T
authors.initials: KT
authors.lastname: Makela
authors.affiliation: Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, MA; Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA.
authors.forename: Henrik
authors.initials: H
authors.lastname: Malchau
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005269:Femur / Q000601:surgery; D006621:Hip Joint / Q000601:surgery; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008670:Metals / Q000097:blood; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012307:Risk Factors
chemical_list: D008670:Metals
keywords: articular surface replacement; hip resurfacing arthroplasty; metal-on-metal; systematic review; total hip arthroplasty