title: A study to develop clinical decision rules for the use of radiography in acute ankle injuries.
abstract: OBJECTIVE
  To develop decision rules that will predict fractures in patients with ankle injuries, thereby assisting clinicians in being more selective in their use of radiography.
  
  
  METHODS
  Prospective survey of emergency department patients over a five-month period.
  
  
  METHODS
  Two university hospital EDs.
  
  
  METHODS
  One hundred fifty-five adults in a pilot stage and 750 in the main study; all presented with acute blunt ankle injuries.
  
  
  METHODS
  Thirty-two standardized clinical variables were assessed and recorded on data sheets by staff emergency physicians before radiography.
  
  
  METHODS
  Variables were assessed for reliability by the kappa coefficient and for association with significant fracture on both ankle and foot radiographic series by univariate analysis. The data then were analyzed by logistic regression and recursive partitioning techniques to develop decision rules for predicting fractures in each radiographic series.
  
  
  RESULTS
  All 70 significant malleolar fractures found in the 689 ankle radiographic series performed were identified among people who had pain near the malleoli and were age 55 years or more, had localized bone tenderness of the posterior edge or tip of either malleolus, or were unable to bear weight both immediately after the injury and in the ED. This rule was 100% sensitive and 40.1% specific for detecting malleolar fractures and would allow a reduction of 36.0% of ankle radiographic series ordered. Similarly, all 32 significant midfoot fractures on the 230 foot radiographic series performed were found among patients with pain in the midfoot and bone tenderness at the base of the fifth metatarsal, the cuboid, or the navicular.
  
  
  CONCLUSIONS
  Highly sensitive decision rules have been developed and will now be validated; these may permit clinicians to confidently reduce the number of radiographs ordered in patients with ankle injuries.
authors.affiliation: Department of Emergency Medicine, Ottawa Civic Hospital, Ontario, Canada.
authors.forename: I G
authors.initials: IG
authors.lastname: Stiell
authors.forename: G H
authors.initials: GH
authors.lastname: Greenberg
authors.forename: R D
authors.initials: RD
authors.lastname: McKnight
authors.forename: R C
authors.initials: RC
authors.lastname: Nair
authors.forename: I
authors.initials: I
authors.lastname: McDowell
authors.forename: J R
authors.initials: JR
authors.lastname: Worthington
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016512:Ankle Injuries / Q000145:classification / Q000000981:diagnostic imaging* / Q000209:etiology; D003661:Decision Support Techniques; D004630:Emergencies; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography