title: High rate of infection after aseptic revision of failed metal-on-metal total hip arthroplasty.
abstract: BACKGROUND
  Evidence suggests some metal-on-metal (MOM) THAs have higher rates of failure and subsequent revision than other bearing surfaces. However, there are few studies demonstrating how these patients fare after revision.
  
  
  OBJECTIVE
  We asked: (1) What is the short-term survivorship of revision THA in patients whose index THAs employed MOM bearings? (2) What are the causes of failure of revision THA in these patients (ie, what are the indications for repeat revision)? (3) What are the most common complications after revisions of MOM THAs?
  
  
  METHODS
  We identified 37 patients (24 women, 13 men; mean age, 55 years; 37 hips) revised for aseptic failure of primary stemmed MOM THAs. Reasons for revision included pain with loose components (n = 19), adverse reaction to metal debris (n = 8), periprosthetic fracture (n = 4), impingement (n = 3), dislocation (n = 2), and pain of unknown origin (n = 1). Minimum followup was 24 months (mean, 33 months; range, 24-81 months) postrevision, but 11 were not seen in the last 2 years as our routine followup is at 2 and 5 years. Clinical histories were reviewed for reasons for failure of the MOM THAs and complications associated with revision surgery.
  
  
  RESULTS
  Survivorship free from further revision for any cause was 95% at 24 months and 92% at latest followup (24-81 months). There were three repeat revisions, all for periprosthetic infection, and all were treated with two-stage reimplantation. No other complications were observed.
  
  
  CONCLUSIONS
  We observed a higher-than-expected rate of infection after revision of MOM THAs. The infection rate was higher in this report than in an earlier series looking at revision THAs for other indications at our institution. As revision of MOM THA becomes more common, it will be important to continue monitoring postrevision outcomes and providing treatment strategies to mitigate complications for these patients.
authors.affiliation: Department of Orthopadic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
authors.forename: Cody C
authors.initials: CC
authors.lastname: Wyles
authors.forename: Robert E
authors.initials: RE
authors.lastname: Van Demark
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Sierra
authors.forename: Robert T
authors.initials: RT
authors.lastname: Trousdale
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation*; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000382:microbiology / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D061825:Metal-on-Metal Joint Prostheses / Q000009:adverse effects*; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000209:etiology* / Q000382:microbiology / Q000601:surgery; D011859:Radiography; D012086:Reoperation; D012307:Risk Factors; D013997:Time Factors; D017211:Treatment Failure