title: Fixed- versus mobile-bearing UKA: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Two design concepts are currently used for unicondylar knee arthroplasty (UKA) prostheses: fixed bearing (FB) and mobile bearing (MB). While MB prostheses have theoretical advantages over their FB counterparts, it is not clear whether they are associated with better outcomes. A systematic review was conducted to examine survivorship differences and differences in failure modes of between FB and MB designs.
  
  
  METHODS
  PubMed, Scirus and Cochrane library databases were searched for medial UKA outcome studies. A total of 44 papers, involving 9,463 knees, were eligible. Outcomes examined included knee function, survivorship and the reasons for, and incidence of, revision for FB and MB prostheses. Random effects meta-analysis was employed to obtain pooled revision rate estimates. Where available, cause-specific time to revision was extracted.
  
  
  RESULTS
  Mean follow-up was 8.7 years for FB and 5.9 years for MB prostheses. There were no other relevant baseline differences. The overall crude revision rate for FB and for MB prostheses was 0.90 (95 % confidence interval (CI) 0.65-1.21) and 1.51 (95 % CI 1.11-1.93) per 100 component years, respectively. After stratification on follow-up time and age, the revision rates were not substantially different, aside for younger patients in short term from studies with short-term follow-up.
  
  
  CONCLUSIONS
  No essential differences between the two designs were observed. MB and FB UKA designs have comparable revision rates. As our study is based on predominantly observational data, with large variations in reporting standards, inferences should be drawn with caution.
  
  
  METHODS
  IV.
authors: Department of Orthopaedic Surgery, Ziekenhuis Netwerk Antwerp, Campus Stuivenberg, Antwerp, Belgium. geert.peersman@telenet.be.
authors: Geert
authors: G
authors: Peersman
authors: Department of Orthopaedic Surgery, St Augustinus ziekenhuis, Antwerp, Belgium.
authors: Bart
authors: B
authors: Stuyts
authors: Department of Orthopaedic Surgery, Ziekenhuis Netwerk Antwerp, Campus Stuivenberg, Antwerp, Belgium.
authors: Tom
authors: T
authors: Vandenlangenbergh
authors: Institu du Genou, Clinique Hartmann, Neuilly sur Seine, Paris, France.
authors: Philippe
authors: P
authors: Cartier
authors: AMR Advanced Medical Research, Hofenstrasse 89b, 8708, Männedorf, Switzerland.
authors: Peter
authors: P
authors: Fennema
mesh_terms: D000328:Adult; D000368:Aged; D001168:Arthritis / Q000601:surgery*; D019645:Arthroplasty, Replacement, Knee; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016032:Randomized Controlled Trials as Topic; D012086:Reoperation
keywords: Arthroplasty; Fixed bearing; Meta-analysis; Mobile bearing; Unicompartmental