title: A 10 year retrospective comparison of the diagnostic usefulness of synovial fluid and synovial biopsy examination.
abstract: OBJECTIVE
  Synovial fluid examination is thought to be the pathological investigation of choice in most joint disorders, with only a few specific conditions necessitating biopsy, although no evidence based studies are available to support this belief. This study sought to investigate the validity of this assumption.
  
  
  METHODS
  One hundred and three cases in which synovial fluid aspiration and synovial biopsy had both been performed at arthroscopy were studied. The amount of diagnostically useful information produced by each investigation was assessed.
  
  
  RESULTS
  In most cases, both investigations provided the same amount of information and were generally equally specific or equally non-specific. Overall, the biopsy provided more information than the fluid in 29% of cases and vice versa in 18%. When only those cases in which both tests were adequate were considered, the biopsy provided more specific information than the fluid in a small number (9%) of cases, but these cases could not be predicted.
  
  
  CONCLUSIONS
  The diagnostic usefulness of a biopsy approximates and occasionally exceeds that of a fluid. In the arthroscopic situation, the main advantage of performing both tests is that it provides a "failsafe mechanism" for the rare occasions when one of the samples is inadequate.
authors.affiliation: Department of Histopathology, Clinical Sciences Building, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK.
authors.forename: J S
authors.initials: JS
authors.lastname: Johnson
authors.forename: A J
authors.initials: AJ
authors.lastname: Freemont
mesh_terms: D001168:Arthritis / Q000473:pathology; D016918:Arthritis, Reactive / Q000473:pathology; D001182:Arthroscopy; D001706:Biopsy; D006801:Humans; D007592:Joint Diseases / Q000473:pathology*; D010003:Osteoarthritis / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013582:Synovial Fluid / Q000166:cytology*; D013583:Synovial Membrane / Q000473:pathology*