Multicentre trial to introduce the Ottawa ankle rules for use of radiography in acute ankle injuries

Abstract Objective: To assess the feasibility and impact of introducing the Ottawa ankle rules to a large number of physicians in a wide variety of hospital and community settings over a prolonged period of time. Design: Multicentre before and after controlled clinical trial. Setting: Emergency departments of eight teaching and community hospitals in Canadian communities (population 10000 to 3000000). Subjects: All 12777 adults (6288 control, 6489 intervention) seen with acute ankle injuries during two 12 month periods before and after the intervention. Intervention: More than 200 physicians of varying experience were taught to order radiography according to the Ottawa ankle rules. Main outcome measures: Referral for ankle and foot radiography. Results: There were significant reductions in use of ankle radiography at all eight hospitals and within a priori subgroups: for all hospitals combined 82.8% control v 60.9% intervention (P<0.001); for community hospitals 86.7% v 61.7%; (P<0.001); for teaching hospitals 77.9% v 59.9%; (P<0.001); for emergency physicians 82.1% v 61.6%; (P<0.001); for family physicians 84.3% v 60.1%; (P<0.001); and for housestaff 82.3% v 60.1%; (P<0.001). Compared with patients without fracture who had radiography during the intervention period those who had no radiography spent less time in the emergency department (54.0 v 86.9 minutes; P<0.001) and had lower medical charges ($70.20 v $161.60; P<0.001). There was no difference in the rate of fractures diagnosed after discharge from the emergency department (0.5 v 0.4%). Conclusions: Introduction of the Ottawa ankle rules proved to be feasible in a large variety of hospital and community settings. Use of the rules over a prolonged period of time by many physicians of varying experience led to a decrease in ankle radiography, waiting times, and costs without an increased rate of missed fractures. The multiphase methodological approach used to develop and implement these rules may be applied to other clinical problems.