title: Levels of evidence at the Orthopaedic Trauma Association annual meetings.
abstract: OBJECTIVE
  To examine the strength of evidence presented at the Orthopaedic Trauma Association (OTA) annual meetings before and after the level of evidence guidelines became popular in the literature.
  
  
  METHODS
  10 years of abstracts from OTA podium presentations, preguidelines (1998-2002), and postguidelines (2007-2011).
  
  
  METHODS
  All abstracts were blinded and randomized for review. Only therapeutic, diagnostic, prognostic, and economic study types were included.
  
  
  METHODS
  Study type and level of evidence were determined for each abstract.
  
  
  RESULTS
  Five hundred thirteen abstracts were included, primarily consisting of therapeutic studies (63%). The distribution of study types between the pre- and postguideline periods was similar (P = 0.37). The levels of evidence for podium presentations in the preguideline period were as follows: level I, 10%; level II, 16%; level III, 14%; and level IV, 60%. The distribution in the postguideline period was as follows: level I, 13%; level II, 2%; level III, 29%; and level IV, 36%. The differences between the pre- and postguideline presentations were significant (P < 0.0001), indicating an improvement in the strength of evidence presented at the annual meetings.
  
  
  CONCLUSIONS
  The majority of podium presentations at the OTA annual meetings are level IV studies; however, there has been a measurable decrease in the number of uncontrolled case series presented at more recent meetings. Encouraging reporting of levels of evidence at future annual meetings has the potential to positively influence the orthopaedic trauma community by improving readers' understanding of the strength of evidence presented, the study design hierarchy, and encouraging investigators to conduct controlled study designs when possible.
authors.affiliation: Department of Orthopaedics, University of British Columbia, Vancouver, Canada.gsloboge@interchange.ubc.ca
authors.forename: Gerard P
authors.initials: GP
authors.lastname: Slobogean
authors.forename: Cassandra
authors.initials: C
authors.lastname: Dielwart
authors.forename: Herman S
authors.initials: HS
authors.lastname: Johal
authors.forename: Jesse A S
authors.initials: JA
authors.lastname: Shantz
authors.forename: Kishore
authors.initials: K
authors.lastname: Mulpuri
mesh_terms: D000465:Algorithms; D003627:Data Interpretation, Statistical; D055317:Evidence-Based Practice / Q000592:standards*; D006801:Humans; D009985:Orthopedics / Q000592:standards*; D010506:Periodicals as Topic / Q000592:standards; D017410:Practice Guidelines as Topic / Q000592:standards*; D012189:Retrospective Studies; D012955:Societies, Medical; D014194:Traumatology / Q000592:standards*