title: Comparative assessment of implantable hip devices with different bearing surfaces: systematic appraisal of evidence.
abstract: OBJECTIVE
  To determine comparative safety and effectiveness of combinations of bearing surfaces of hip implants.
  
  
  METHODS
  Systematic review of clinical trials, observational studies, and registries.
  
  
  METHODS
  Medline, Embase, Cochrane Controlled Trials Register, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the United States Food and Drug Administration.
  
  
  METHODS
  Criteria for inclusion were comparative studies in adults reporting information for various combinations of bearings (such as metal on metal and ceramic on ceramic). Data search, abstraction, and analyses were independently performed and confirmed by at least two authors. Qualitative data syntheses were performed.
  
  
  RESULTS
  There were 3139 patients and 3404 hips enrolled in 18 comparative studies and over 830 000 operations in national registries. The mean age range in the trials was 42-71, and 26-88% were women. Disease specific functional outcomes and general quality of life scores were no different or they favoured patients receiving metal on polyethylene rather than metal on metal in the trials. While one clinical study reported fewer dislocations associated with metal on metal implants, in the three largest national registries there was evidence of higher rates of implant revision associated with metal on metal implants compared with metal on polyethylene. One trial reported fewer revisions with ceramic on ceramic compared with metal on polyethylene implants, but data from national registries did not support this finding.
  
  
  CONCLUSIONS
  There is limited evidence regarding comparative effectiveness of various hip implant bearings. Results do not indicate any advantage for metal on metal or ceramic on ceramic implants compared with traditional metal on polyethylene or ceramic on polyethylene bearings.
authors: Weill Cornell Medical College, New York, NY 10065, USA. ars2013@med.cornell.edu
authors: Art
authors: A
authors: Sedrakyan
authors: Sharon-Lise T
authors: SL
authors: Normand
authors: Stefan
authors: S
authors: Dabic
authors: Samantha
authors: S
authors: Jacobs
authors: Stephen
authors: S
authors: Graves
authors: Danica
authors: D
authors: Marinac-Dabic
mesh_terms: D002516:Ceramics; D002858:Chromium Alloys; D005260:Female; D006622:Hip Prosthesis / Q000592:standards; D006801:Humans; D007592:Joint Diseases / Q000601:surgery; D008297:Male; D020959:Polyethylene; D011474:Prosthesis Design; D020127:Recovery of Function; D012086:Reoperation; D012449:Safety; D016896:Treatment Outcome
chemical_list: D002858:Chromium Alloys; D020959:Polyethylene