Implementation of the Ottawa Knee Rule for the Use of Radiography in Acute Knee Injuries

Stiell, Ian G. MD, MSc, FRCPC
Wells, George A. PhD
Hoag, Roger H. MD, FRCPC
Sivilotti, Marco L. A. MD, MSc, FRCPC
Cacciotti, Teresa F. RN
Verbeek, P. Richard MD, FRCPC
Greenway, Keith T. MD, FRCPC
McDowell, Ian PhD
Cwinn, A. Adam MD, FRCPC
Greenberg, Gary H. MD, FRCPC
Nichol, Graham MD, FRCPC
Michael, John A. MD, FRCPC

From the Division of Emergency Medicine (Drs Stiell, Sivilotti, Cwinn, Greenberg, and Michael), the Department of Medicine (Drs Wells and Nichol), the Department of Epidemiology and Community Medicine (Dr McDowell), and the Clinical Epidemiology Unit (Ms Cacciotti), University of Ottawa, Ottawa, Ontario; the Department of Emergency Medicine (Dr Hoag), Queensway-Carleton Hospital, Nepean, Ontario; the Division of Emergency Medicine (Dr Verbeek), University of Toronto, Toronto, Ontario; the Department of Emergency Medicine (Dr Greenway), Peel Memorial Hospital, Brampton, Ontario.

JAMA: The Journal of the American Medical Association 278(23):p 2075-2079, December 17, 1997.

Context

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.

Design

Controlled clinical trial with before-after and concurrent controls.

Setting

Emergency departments of 2 teaching and 2 community hospitals.

Patients

All 3907 consecutive eligible adults seen with acute knee injuries during two 12-month periods before and after the intervention.

Intervention

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.

Main Outcome Measures

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 kappa 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.

JAMA.1997;278:2075-2079