Implementation of the Ottawa ankle rules in France. A multicenter randomized controlled trial

OBJECTIVES: To assess the impact of the implementation of the Ottawa ankle rules on radiography requests in French hospitals during a 5-month intervention period and the impact of using posters alone to sustain the effect of the rules during a 5-month postintervention period. DESIGN: Multicenter randomized controlled trial preceded and followed by observational studies of radiological practices. SETTING: The emergency departments of 5 Paris university teaching hospitals of the Assistance Publique-H?pitaux de Paris. PATIENTS: A total of 2218, 1911, and 851 patients-all aged 18 years and older-who were seen for acute ankle or midfoot injuries in emergency departments during preintervention, intervention, and postintervention periods, respectively. INTERVENTION: Implementation of the Ottawa ankle rules by emergency department physicians in the intervention hospitals (using meetings, posters, pocket cards, and data forms). During the postintervention period, posters alone were used to sustain the intervention effect. MAIN OUTCOME MEASURE: Percentage of patients for whom radiography was requested. RESULTS: During the preintervention period, 98% and 98.5% of patients were referred for radiography in the intervention and control groups, respectively. During the intervention period, the mean proportions of patients referred for radiography by physicians was 78.9% in the intervention group and 99% in the control group (P=.03). Between preintervention and intervention periods, a relative reduction of 22.4% (95% confidence interval [CI], 19.8%-24.9%) in radiography requests was observed in the intervention group, while requests increased by 0.5% (95% CI, 0%-1.4%) in the control group. During the postintervention period, the proportion of radiography requests in the intervention hospitals was lower than the proportion observed in the preintervention period (83.1% vs 98%). CONCLUSIONS: Implementation of the Ottawa ankle rules significantly reduced radiography requests in French hospitals. Using a minimal postintervention implementation strategy, the effect of this intervention decreased but persisted after it was discontinued.