title: Increase in quality and quantity of orthopaedic studies from 2002 to 2012.
abstract: OBJECTIVE
  To compare the level of evidence of orthopaedic studies published in 2002 and 2012 to determine whether the quality and quantity of studies have increased.
  
  
  METHODS
  The top 10 orthopaedic journals in 2002 and 2012 were identified, according to the Thomson Reuters impact factor. The level of evidence of each clinical article between January and June in 2002 and 2012 were determined by 2 senior orthopaedic trainees, according to the Oxford Centre for Evidence-based Medicine 2011 Levels of Evidence. Basic science articles, case reports, and non-systematic reviews were excluded. The proportions of papers designated to each level of evidence in 2002 and 2012 were compared, as was the mean level of evidence of studies in 2002 and 2012.
  
  
  RESULTS
  In 2002, 379 clinical articles were identified and their level of evidence was level 1 (n=3), level 2 (n=67), level 3 (n=71), and level 4 (n=238). In 2012, 642 clinical articles were identified and their level of evidence was level 1 (n=26), level 2 (n=113), level 3 (n=167), and level 4 (n=336). The proportion of level 4 articles decreased from 62.8% in 2002 to 52.3% in 2012 (p=0.001), whereas the proportion of level 1 articles increased from 0.8% to 4.1% (p=0.002) and level 3 articles increased from 18.7% to 26.0% (p=0.008). The mean level of evidence improved from 3.44 in 2002 to 3.27 in 2012 (p=0.002).
  
  
  CONCLUSIONS
  The quality and quantity of orthopaedic studies have increased from 2002 to 2012, but most studies remained of a low level of evidence.
authors.affiliation: Northwick Park Hospital, London, United Kingdom.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Little
authors.affiliation: Chelsea and Westminster Hospital, London, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Newman
authors.affiliation: St Mary's Hospital, London, United Kingdom.
authors.forename: Alex
authors.initials: A
authors.lastname: Dodds
authors.affiliation: St Mary's Hospital, London, United Kingdom.
authors.forename: Dominic
authors.initials: D
authors.lastname: Spicer
mesh_terms: D035843:Biomedical Research / Q000706:statistics & numerical data*; D019317:Evidence-Based Medicine / Q000379:methods*; D006801:Humans; D055811:Journal Impact Factor; D009985:Orthopedics; D010506:Periodicals as Topic / Q000706:statistics & numerical data*
keywords: evidence-based medicine; journal impact factor; publications; research