title: Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries.
abstract: BACKGROUND
  The Ottawa Knee Rule is a previously validated clinical decision rule that was developed to allow physicians to be more selective and efficient in their use of plain radiography for patients with acute knee injuries.
  
  
  OBJECTIVE
  To assess the impact on clinical practice of implementing the Ottawa Knee Rule.
  
  
  METHODS
  Controlled clinical trial with before-after and concurrent controls.
  
  
  METHODS
  Emergency departments of 2 teaching and 2 community hospitals.
  
  
  METHODS
  All 3907 consecutive eligible adults seen with acute knee injuries during two 12-month periods before and after the intervention.
  
  
  METHODS
  During the after period in the 2 intervention hospitals, the Ottawa Knee Rule was taught to all house staff and attending physicians who were encouraged to order knee radiography according to the rule.
  
  
  METHODS
  Referral for knee radiography, accuracy and reliability of the rule, mean time in emergency department, and mean charges.
  
  
  RESULTS
  There was a relative reduction of 26.4% in the proportion of patients referred for knee radiography in the intervention group (77.6% vs 57.1 %; P<.001), but a relative reduction of only 1.3% in the control group (76.9% vs 75.9%; P=.60). These changes over time were significant when the intervention and control groups were compared (P<.001). The rule was found to have a sensitivity of 1.0 (95% confidence interval [CI], 0.94-1.0) for detecting 58 knee fractures. The K coefficient for interpretation of the rule was 0.91 (95% CI, 0.82-1.0). Compared with nonfracture patients who underwent radiography during the after-intervention period, those discharged without radiography spent less time in the emergency department (85.7 minutes vs 118.8 minutes) and incurred lower estimated total medical charges for physician visits and radiography (US $80 vs US $183).
  
  
  CONCLUSIONS
  Implementation of the Ottawa Knee Rule led to a decrease in use of knee radiography without patient dissatisfaction or missed fractures and was associated with reduced waiting times and costs. Widespread use of the rule could lead to important health care savings without jeopardizing patient care.
authors.affiliation: Division of Emergency Medicine, University of Ottawa, Ontario, Canada.
authors.forename: I G
authors.initials: IG
authors.lastname: Stiell
authors.forename: G A
authors.initials: GA
authors.lastname: Wells
authors.forename: R H
authors.initials: RH
authors.lastname: Hoag
authors.forename: M L
authors.initials: ML
authors.lastname: Sivilotti
authors.forename: T F
authors.initials: TF
authors.lastname: Cacciotti
authors.forename: P R
authors.initials: PR
authors.lastname: Verbeek
authors.forename: K T
authors.initials: KT
authors.lastname: Greenway
authors.forename: I
authors.initials: I
authors.lastname: McDowell
authors.forename: A A
authors.initials: AA
authors.lastname: Cwinn
authors.forename: G H
authors.initials: GH
authors.lastname: Greenberg
authors.forename: G
authors.initials: G
authors.lastname: Nichol
authors.forename: J A
authors.initials: JA
authors.lastname: Michael
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D020000:Decision Support Systems, Clinical; D004636:Emergency Service, Hospital / Q000191:economics / Q000592:standards; D005260:Female; D050723:Fractures, Bone / Q000000981:diagnostic imaging; D017408:Guidelines as Topic; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009864:Ontario; D011859:Radiography / Q000191:economics / Q000592:standards / Q000706:statistics & numerical data*