Multicentre trial to introduce the Ottawa ankle rules for use of radiography in acute ankle injuries Ian Stiell, George Wells, Andreas Laupacis, Robert Brison, Richard Verbeek, Katherine Vandemheen, C David Naylor for the Multicentre Ankle Rule Study Group Abstract of varying experience led to a decrease in ankle Objective-To assess the feasibility and impact of radiography, waiting times, and costs without an introducing the Ottawa ankle rules to a large number increased rate of missed fractures. The multiphase of physicians in a wide variety of hospital and methodological approach used to develop and imple- community settings over a prolonged period oftime. ment these rules may be applied to other clinical Design-Multicentre before and after controlled problems. Clinical Epidemiology clinical trial. Unit, Loeb Medical Setting-Emergency departments of eight Research Institute, Ottawa, Introduction Ontario, Canada K1Y 4E9 teaching and community hospitals in Canadian com- are a common Ian Stiell, associate professor munities (population 10 000 to 3 000 000). Ankle and foot injuries complaint George Wells, associate Subjects-All 12 777 adults (6288 control, 6489 among patients seen in emergency departments. professor intervention) seen with acute ankle injuries during Though only a few of these cases have suffered a Andreas Laupacis, associate two 12 month periods before and after the interven- fracture,'-6 nearly all typically undergo plain radio- professor tion. graphy of the ankle or foot, or both.'2 To deal with Katherine Vandemheen, Intervention-More than 200 physicians of vary- this clinical problem decision rules for the use of research coordinator ing experience were taught to order radiography radiography in acute ankle injuries have been recently according to the Ottawa ankle rules. developed'3 14 and validated'5 and have been found to be Division ofEmergency highly sensitive in identifying fractures. These Ottawa Medicine, Queens Main outcome measures-Referral for ankle and University, Kingston, foot radiography. ankle rules are based on the assessment of ability to Ontario, Canada Results-There were significant reductions in bear weight and areas of bone tenderness and allow Robert Brison, associate use of ankle radiography at all eight hospitals physicians to determine quickly which patients are at professor and within a priori subgroups: for all hospitals com- negligible risk offracture (figure). bined 828/8% control v 60-9%'/o intervention (P< 0.001); We know of few clinical decision rules that have Division ofEmergency for community hospitals 86*7% v 61-7%; (P<0.001); been studied to determine their impact on patient care Medicine, University of for teaching hospitals 77-9% v 59 9%/o; (P< 0.001); for in "usual clinical practice."'6 17 A recent study at a Toronto, Toronto, single hospital showed that implementation of the Canada emergency physicians 82-1% v 61-6%; (P<0-001); Ontario, Ottawa rules to a in Richard Verbeek, assistant for family physicians 84-3% v 60/1%; (P<0.001); and ankle led significant reduction the professor for housestaff 82*3% v 60.1%; (P <0.001). Compared use of ankle radiography.'8 This clinical trial was with patients without fracture who had radiography designed to assess whether the rules could be shown to Institute for Clinical during the intervention period those who had no reduce the use of radiography without affecting quality Evaluative Sciences in radiography spent less time in the emergency depart- of care when used by many physicians of varying Ontario, Toronto, Ontario, ment (54.0 v 86-9 minutes; P<0-001) and had lower experience in a variety ofdifferent hospital settings. Canada medical charges ($70.20 v $161.60; P<0.001). There C David Naylor, chief was no difference in the rate of fractures diagnosed executive and methods after discharge from the emergency department (0 5 Subjects officer SUBJECTS v 04%). All adult with ankle seen in the Correspondence to: Conclusions-Introduction of the Ottawa ankle patients injury Dr Stiell. rules proved to be feasible in a large variety of emergency departments of the study hospitals during hospital and community settings. Use of the rules control (before) and intervention (after) periods of 12 BMY 1995;311:594-7 over a prolonged period of time by many physicians months each were included in this controlled clinical trial. The eight hospitals were chosen because they were able to identify eligible cases retrospectively Lateral view Medial view and because they represented various community population sizes (10000 to 3000000), hospital types (community, teaching), annual volumes of patients in A Posterior edge B Posterior edge emergency departments (20 000 to 68 000), and staffing or tip of lateral or tip of medial patterns (emergency physician, family physician, malleolus 6cm 6cm - malleolus house officers). Patients with acute ankle trauma from any mechanism of injury were eligible. "Ankle" was explicitly defined anatomically." 19 The institutional C Base of Sth- research ethics committees approved the study. metatarsal -D Navicular INTERVENTION We introduced the Ottawa ankle rules'5 to the study hospitals before the intervention period by means of a An ankle x ray series is required only if there A foot x ray series is required only if there is any pain in malleolar zone and any of these is any pain in midfoot zone and any of these single one hour lecture given by the principal investi- findings: findings gator (IS) as well as handouts, pocket cards, and two * Bone tenderness at A * Bone tenderness at C posters mounted in each department. Physicians were * Bone tenderness at B * Bone tenderness at D asked to complete a data form and to distribute * Inability to bear weight both immediately * Inability to bear weight both immediately information sheets to patients. The decision to order in in and emergency department and emergency department radiography for individual patients was solely at the Ottawa ankle rulesfor use ofradiography in acute ankle injuries (adaptedfrom Stiell et aPl) discretion ofthe treating physician. 594 BMJ VOLUME 311 2 SEPT-EMBER 1995 OUTCOME MEASURES who had not improved according to explicit criteria For both study periods review of patients' eligibility regarding pain, ambulation, and ability to work were was made from patients' records independently for asked to return for assessment. Patients who had each case by three members of the research team, and fractures diagnosed after discharge were questioned differences were resolved by consensus. Patients' after six months about possible effects. For patients records were identified (retrospectively for the control followed up by telephone calls the total charges for all period and prospectively for the intervention period) in emergency department and follow up physician visits a consistent fashion by a combination of computerised and radiographic series were estimaed in 1993 US retrieval from International Classification of Diseases dollars. (ninth revision) diagnostic codes and a search of daily census logs. The primary outcome measure, the STATISTICAL ANALYSIS proportion of patients referred for radiography of All patients who met the inclusion-exclusion criteria the ankle, was determined from radiology reports. during the control and intervention periods were Clinically important features were defined as fractures included in the analysis regardless of whether physi- greater than three millimetres in breadth. cians completed a data collection form or were During the intervention period only, all patients compliant with the decision rules. For each hospital without fracture were followed up by telephone call at separately the uncorrected XI analysis was used to test 10 days if they had had neither ankle nor foot the primary hypothesis that there was no difference in radiography or if they were seen during the first seven the proportion of patients referred for a standard ankle days of each month and did have radiography. Patients radiographic series between the control and interven- tion study groups. We calculated 95% confidence TABLE i-Characteristics of all patients with ankle injury seen at study intervals of the in hospitals during 12 month control and intervention study periods. relative differences referral rates Figures are numbers (percentages) ofpatients unless stated otherwise for radiography between groups.20 Overall point and confidence interval estimates for the relative Control Intervention reductions were also derived. A similar analysis was Characteristic (n-6288) (n= 6489) used to test the secondary hypothesis that there was no Median (range) age (years) 32 (18-101) 32 (18-100) difference in the referral for radiographic series of the No (%) ofmen 3398 (54 0) 3384 (52-1) foot. Important fractures 1030 (16-4) 1082 (16-7) X2 Malleolar region* 768 (12-2) 796 (12-3) We used analysis to compare the primary outcome Lateral malleolus 413 460 between the control and intervention study periods Medial malleolus 81 72 within the a priori subgroups of hospital type (com- Posterior malleolus 35 26 Bimalleolar 127 115 munity, teaching) and physician type (emergency, Trimalleolar 79 98 family, housestaff). Comparisons of characteristics of Talus 49 31 Midfoot* 271 (4 3) 294 (4 5) patients and other outcomes were tested with x2, Base 5th metatarsal 220 254 Student's t test, or Mann-Whitney test as appropriate. Navicular 29 22 Anterior process calcaneus 26 12 An absolute change of 10% for the referral rate for Cuboid 12 7 ankle radiography from the estimated