title: Level of evidence of presentations at American Academy of Orthopaedic Surgeons annual meetings.
abstract: BACKGROUND
  The American Academy of Orthopaedic Surgeons (AAOS) Annual Meeting is a major international forum for scientific exchange and education. The purpose of this study was to evaluate the level of evidence of papers and posters presented at the 2001, 2004, 2007, and 2010 AAOS meetings to determine trends in the quality of study designs between the years 2001 and 2010.
  
  
  METHODS
  Abstracts for AAOS presentations from 2001 (288 papers and 468 posters), 2004 (290 papers and 466 posters), 2007 (525 papers and 541 posters), and 2010 (720 papers and 569 posters) were independently evaluated by three reviewers. The level of evidence of each presentation was determined based on the AAOS classification system. The results were subdivided according to orthopaedic subspecialty and type of presentation.
  
  
  RESULTS
  In subsequent years, there was a substantial increase in the percentage of Level I studies (2% in 2001, 3% in 2004, 5% in 2007, and 7% in 2010), Level II studies (15% in 2001, 18% in 2004, 23% in 2007, and 29% in 2010), and Level III studies (22% in 2001, 26% in 2004, 29% in 2007, and 33% in 2010), with a concomitant decrease in the percentage of Level IV studies (62% in 2001, 54% in 2004, 43% in 2007, and 31% in 2010). Overall, there was a significant nonrandom improvement in the level of evidence of presentations over the study period (p &lt; 0.001). This trend was consistent across all orthopaedic subspecialties and in both the paper and the poster subgroups.
  
  
  CONCLUSIONS
  The level of evidence of studies presented at the AAOS Annual Meeting is steadily increasing, which signifies a mark of continual improvement in the quality of the scientific program.
authors.affiliation: Department of Orthopaedic Surgery, Hospital of the University of Pennsylvania, 3400 Spruce Street, 2 Silverstein, Philadelphia, PA 19104, USA.
authors.forename: Pramod B
authors.initials: PB
authors.lastname: Voleti
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Donegan
authors.forename: Keith D
authors.initials: KD
authors.lastname: Baldwin
authors.forename: Gwo-Chin
authors.initials: GC
authors.lastname: Lee
mesh_terms: D035843:Biomedical Research / Q000592:standards / Q000639:trends*; D002986:Clinical Trials as Topic / Q000592:standards / Q000639:trends*; D006801:Humans; D009985:Orthopedics / Q000592:standards / Q000639:trends*; D012107:Research Design / Q000592:standards / Q000639:trends*; D012955:Societies, Medical; D014481:United States