title: External validation of the Ottawa knee rules in an urban trauma center in the United States.
abstract: OBJECTIVE
  We evaluated the Ottawa knee rules in a high-volume teaching hospital in the United States to determine whether the rules could be safely used to decide whether patients with acute blunt knee trauma should undergo radiography.
  
  
  METHODS
  During a 13-month period, 378 patients with acute blunt knee trauma were prospectively examined using the Ottawa knee rules. Data collected included the presence or absence of fracture predictors and the results of radiography.
  
  
  RESULTS
  A fracture was seen in 43 (11%) of the 378 patients who met inclusion criteria. The knee rules predicted 42 of the 43 fractures; sensitivity was 98%, and specificity was 19%. Radiography of 65 patients (17%) who had no predictors for fracture could have been avoided if the knee rules had been used to screen for radiography.
  
  
  CONCLUSIONS
  The Ottawa knee rules are highly sensitive for fracture in this setting and may safely be used to decide whether patients with acute blunt knee trauma should undergo radiography.
authors.affiliation: Emory University School of Medicine, The Emory Clinic, Atlanta, GA 30322, USA.
authors.forename: S
authors.initials: S
authors.lastname: Tigges
authors.forename: S
authors.initials: S
authors.lastname: Pitts
authors.forename: S
authors.initials: S
authors.lastname: Mukundan
authors.forename: D
authors.initials: D
authors.lastname: Morrison
authors.forename: M
authors.initials: M
authors.lastname: Olson
authors.forename: A
authors.initials: A
authors.lastname: Shahriara
mesh_terms: D000328:Adult; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis / Q000000981:diagnostic imaging; D006784:Hospitals, Teaching; D006786:Hospitals, Urban; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis*; D008297:Male; D011237:Predictive Value of Tests; D011859:Radiography; D012680:Sensitivity and Specificity; D014193:Trauma Centers