title: Validation of the Ottawa Ankle Rules in children with ankle injuries.
abstract: OBJECTIVE
  The Ottawa Ankle Rules (OAR) have been found to be 100% sensitive in adult patients with ankle injuries, and application of the OAR has resulted in a 28% reduction in the number of x-rays ordered. The objectives of this study were to determine the sensitivity and specificity of the OAR in children and to determine the potential change in x-ray utilization.
  
  
  METHODS
  Children, aged 2-16 years, presenting to the EDs of two children's hospitals, with an ankle injury in the previous 48 hours, were enrolled. All patients were assessed by either staff physicians or fellows. X-rays were ordered according to standard clinical practice. Prior to reviewing x-rays, the physical examination was recorded on a standardized form. Positive outcomes (clinically significant) were defined as fractures with fragments > or =3 mm. Patients not x-rayed and asymptomatic at five to seven days postinjury were considered to have no significant fracture.
  
  
  RESULTS
  Six hundred seventy patients were enrolled. The OAR were 100% sensitive (95% CI = 95% to 100%) for significant ankle fractures, with a specificity of 24% (95% CI = 20% to 28%). The OAR were 100% sensitive (95% CI = 82% to 100%) for the midfoot, with a specificity of 36% (95% CI = 29% to 43%). If the OAR had been followed, there would have been a reduction of ankle x-rays by 16% and foot x-rays by 29% without missing any clinically significant fracture. However, analysis of the two hospitals showed that if the rules had been applied, one would have a reduction in x-rays, while the other center would have an increase.
  
  
  CONCLUSIONS
  This study demonstrates the OAR to be sensitive for detecting clinically significant (> or =3 mm) ankle and midfoot fractures in children. The application of these rules may reduce the number of x-rays ordered. A further study is required to determine the effect of using the OAR in clinical practice.
authors.affiliation: Department of Pediatrics, Children's Hospital of Eastern Ontario, University of Ottawa, Canada. plinta@travel-net.com
authors.forename: A C
authors.initials: AC
authors.lastname: Plint
authors.forename: B
authors.initials: B
authors.lastname: Bulloch
authors.forename: M H
authors.initials: MH
authors.lastname: Osmond
authors.forename: I
authors.initials: I
authors.lastname: Stiell
authors.forename: H
authors.initials: H
authors.lastname: Dunlap
authors.forename: M
authors.initials: M
authors.lastname: Reed
authors.forename: M
authors.initials: M
authors.lastname: Tenenbein
authors.forename: T P
authors.initials: TP
authors.lastname: Klassen
mesh_terms: D000293:Adolescent; D016512:Ankle Injuries / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D003955:Diagnostic Tests, Routine; D005260:Female; D050723:Fractures, Bone / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011859:Radiography; D012680:Sensitivity and Specificity