Ankle References ================ DECISION RULES FOR THE USE OF RADIOGRAPHY IN ACUTE ANKLE INJURIES Stiell, I.G., et al, JAMA 269(9):1127, March 3, 1993 BACKGROUND: It has been estimated that more than five million ankle x-ray series are ordered yearly in the U.S. and Canada, but that fewer than 15% are positive for fracture. To date, no guidelines have become widely accepted for the use of radiography in patients with acute ankle injuries. METHODS: The authors, from the University of Ottawa in Canada, prospectively examined the validity of their previously formulated decision rules for obtaining ankle or foot x-rays in adults presenting with injuries due to blunt trauma. The decision rules were examined and refined in a total of 1,032 patients in the initial study phase, and the refined decision rules were validated in 453 additional patients. RESULTS: The refined decision rule calls for ankle x-rays only in patients with bone tenderness at the posterior edge or tip of the lateral or medial malleolus, or with inability to bear weight both immediately and in the emergency department. Prospective application of these refined criteria identified all of the patients with clinically significant ankle fractures (sensitivity, 100%; specificity, 49%). The refined decision rule for midfoot injuries calls for x-rays in patients with bone tenderness at the base of the fifth metatarsal or the navicular, or with inability to bear weight immediately and in the ED. These refined criteria had a 100% sensitivity, and 79% specificity, for clinically significant midfoot fractures on prospective validation. Application of the criteria would have reduced the use of radiography in this study sample by 30%. CONCLUSIONS: The authors consider these "Ottawa ankle rules" to be reliable predictors of clinically significant fractures in adults with acute blunt ankle trauma. 47 references COST-EFFECTIVENESS ANALYSIS OF THE OTTAWA ANKLE RULES Anis, A.H., et al, Ann Emerg Med 26(4):422, October 1995 BACKGROUND: Each year in the U.S. and Canada, about 3 million patients present to emergency departments with acute ankle injuries. Although more than 85% do not have fractures, nearly all undergo x-ray studies. The Ottawa Ankle Rules have been reported to be highly sensitive in selecting patients likely to benefit from x-rays, but have not been widely incorporated into clinical practice. METHODS: This decision analysis, from the Universities of British Columbia and Ottawa, evaluated the cost effectiveness of use of the Ottawa Ankle Rules. Medical and societal costs were calculated for cohorts of patients managed with and without the rules. A sensitivity analysis was conducted in which the negative predictive value of the rules was reduced from 100% to 98.5%, assuming 1.5 missed fractures in every 100 patients not undergoing x-rays. RESULTS: In the baseline analysis, the incremental cost saving per patient (in 1993 currency) under Medicare, Medicaid and hospital charge systems in the U.S. were $8.91, $7.45 and $32.92, respectively ($8.89 in Canada). If the negative predictive value were reduced to 98.5%, the incremental cost saving per patient was $7.54, $6.14, $31.46, and $7.30, respectively. Use of the decision rule was considered cost effective even if each lawsuit resulting from missed fractures resulted in payment of maximum indemnities ($185,000 in the U.S.), and if the threshold for initiation of litigation for a missed fracture did not exceed up to about 70% in the U.S. and 50% in Canada (baseline probability, 0.05% and 0.01%, respectively). CONCLUSIONS: These findings suggest that the Ottawa Ankle Rules are highly cost effective, and support their implementation in clinical practice. 25 references Copyright 1996 by Emergency Medical Abstracts - All Rights Reserved 1/96 - #19 FAILED VALIDATION OF A CLINICAL DECISION RULE FOR THE USE OF RADIOGRAPHY IN ACUTE ANKLE INJURY Kerr, L., et al, N Z Med J 107(982):294, July 27, 1994 BACKGROUND: Acute ankle injuries account for 3-12% of emergency department visits. Although most of these patients (80-95%) undergo x-rays, the fracture yield is only 7-36%. Various sets of guidelines have been proposed to reduce unnecessary use of x-rays in patients with ankle injuries, but none has gained wide acceptance. METHODS: This prospective, multicenter study, based in New Zealand, evaluated the reliability of the recently developed Ottawa clinical decision rules for ankle radiography in 350 patients presenting with acute nonpenetrating ankle injuries. Essentially, the Ottawa decision rule indicates that x-rays are necessary only in patients aged 55 or older or in those with pain near the malleoli who are unable to bear weight both immediately after the injury and for four steps in the emergency department, or in those having bony tenderness at the posterior edge or tip of either malleolus. METHODS: Ankle fractures were identified in 21% of the patients. The sensitivity of the Ottawa clinical decision rule was 93% and the specificity was 11%. The false-negative rate was 14% and the positive predictive value was 22%. Use of the decision rule would have reduced performance of x-rays by only 10%. The five fractures that would have been missed included one unstable fracture of the distal fibula, and one talar, calcaneal, cuboid and navicular fracture. CONCLUSIONS: Although the Ottawa clinical decision rule for use of radiography in patients with acute ankle injuries has been previously reported to be 100% sensitive and to reduce use of x-rays by 36%, the authors of the current study found that use of this instrument would have a minimal impact on use of x-rays and an unacceptable false-negative rate. 15 references Acad Emerg Med 1997 Aug;4(8):776-779 Ankle radiograph utilization after learning a decision rule: a 12-month follow-up. Verbeek PR, Stiell IG, Hebert G, Sellens C Department of Emergency Services, Sunnybrook Health Science Centre, Toronto, ON, Canada. r.verbeek@utoronto.ca OBJECTIVE: To test whether the reduction in ankle radiograph ordering was sustained during a 12-month period after a formal trial to introduce the Ottawa ankle rules. METHODS: A before-after clinical trial of ankle radiograph ordering practice was performed in a university-based ED. All 1,884 (947 "during intervention," 937 "postintervention") adults seen with acute ankle injuries during 2 12-month trial periods were evaluated. The behavioral intervention was the teaching of the Ottawa ankle rules and feedback of compliance with the rules during the intervention period. No further education about the ankle rules or feedback regarding compliance occurred during the postintervention year. Physicians were unaware of any postintervention surveillance. The primary outcome was the proportion of eligible patients referred for an ankle radiograph during the intervention and postintervention periods. RESULTS: During the intervention period (January 1-December 31, 1993), the proportion of patients who received an ankle radiograph [609 x-rayed of 947 patients seen (64.3%; 95% CI 61.2-67.4%)] did not differ from the proportion who received an x-ray in the postintervention period (January 1-December 31, 1994) [583 x-rayed of 937 patients seen (62.2%; 95% CI 59.1-65.3%), p = 0.65, power > 0.80 to detect a 10% increase in the radiograph ordering rate]. There was also no difference in the radiograph ordering rate in the first 3 months of the postintervention period compared with the last 3 months of the postintervention period (68.8% vs 64.7%, respectively, p > 0.30). CONCLUSIONS: Compliance with the Ottawa ankle rules was sustained during a 12-month postintervention surveillance period when physicians did not know they were being observed. Physicians will continue to use a simple clinical guideline once it has been learned. Can Fam Physician 1996 Mar;42:478-480 Ottawa ankle rules. Stiell I Medical Research Council of Canada Research Personnel Program, Ottawa. The Ottawa ankle rule project demonstrated that more than 95% of patients with ankle injuries had radiographic examinations but that 85% of the films showed no fractures. A group of Ottawa emergency physicians developed two rules to identify clinically important fractures of the malleoli and the midfoot. Use of these rules reduced radiographic examinations by 28% for the ankle and 14% for the foot. Other Formats: Links: BMJ 1995 Sep 2;311(7005):594-597 Multicentre trial to introduce the Ottawa ankle rules for use of radiography in acute ankle injuries. Multicentre Ankle Rule Study Group. Stiell I, Wells G, Laupacis A, Brison R, Verbeek R, Vandemheen K, Naylor CD Clinical Epidemiology Unit, Loeb Medical Research Institute, Ottawa, Ontario, Canada. 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 10,000 to 3,000,000). SUBJECTS--All 12,777 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. Other Formats: Links: N Z Med J 1994 Jul 27;107(982):294-295 Failed validation of a clinical decision rule for the use of radiography in acute ankle injury. Published erratum appears in N Z Med J 1994 Sep 14;107(985):363 Kelly AM, Richards D, Kerr L, Grant J, O'Donovan P, Basire K, Graham R Emergency Department Hutt Hospital, Lower Hutt, New Zealand. AIM. To validate the Ottawa clinical decision rule for the use of radiography in acute ankle injuries. METHOD. A prospective, multicentre trial of 350 adult patients presenting with acute ankle injuries consisting of correlation of the features of the Ottawa clinical decision rule with the results of x-rays. RESULTS. There were 75 fractures in 350 patients, five of which would have been missed by the clinical decision rule. The sensitivity of the rule was 93% with a specificity of 11%. The positive predictive value was 22%, the false negative rate 14%. Fractures that would have been missed by the clinical decision rule included one unstable fracture of the ankle, one fracture of the talus, one calcaneal fracture and one fracture each of the cuboid and navicular. CONCLUSION. The Ottawa clinical decision rule for the use of radiography in acute ankle injuries is unacceptable for application in emergency departments in New Zealand due to a high false negative rate. Other Formats: Links: JAMA 1993 Mar 3;269(9):1127-1132 Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, Stewart JP, Maloney J Division of Emergency Medicine, University of Ottawa, Ontario, Faculty of Medicine, Canada. OBJECTIVE--To validate and refine previously derived clinical decision rules that aid the efficient use of radiography in acute ankle injuries. DESIGN--Survey prospectively administered in two stages: validation and refinement of the original rules (first stage) and validation of the refined rules (second stage). SETTING--Emergency departments of two university hospitals. PATIENTS--Convenience sample of adults with acute ankle injuries: 1032 of 1130 eligible patients in the first stage and 453 of 530 eligible patients in the second stage. MAIN OUTCOME MEASURES--Attending emergency physicians assessed each patient for standardized clinical variables and classified the need for radiography according to the original (first stage) and the refined (second stage) decision rules. The decision rules were assessed for their ability to correctly identify the criterion standard of fractures on ankle and foot radiographic series. The original decision rules were refined by univariate and recursive partitioning analyses. MAIN RESULTS--In the first stage, the original decision rules were found to have sensitivities of 1.0 (95% confidence interval [CI], 0.97 to 1.0) for detecting 121 maleolar zone fractures, and 0.98 (95% CI, 0.88 to 1.0) for detecting 49 midfoot zone fractures. For interpretation of the rules in 116 patients, kappa values were 0.56 for the ankle series rule and 0.69 for the foot series rule. Recursive partitioning of 20 predictor variables yielded refined decision rules for ankle and foot radiographic series. In the second stage, the refined rules proved to have sensitivities of 1.0 (95% CI, 0.93 to 1.0) for 50 malleolar zone fractures, and 1.0 (95% CI, 0.83 to 1.0) for 19 midfoot zone fractures. The potential reduction in radiography is estimated to be 34% for the ankle series and 30% for the foot series. The probability of fracture, if the corresponding decision rule were "negative," is estimated to be 0% (95% CI, 0% to 0.8%) in the ankle series, and 0% (95% CI, 0% to 0.4%) in the foot series. CONCLUSION--Refinement and validation have shown the Ottawa ankle rules to be 100% sensitive for fractures, to be reliable, and to have the potential to allow physicians to safely reduce the number of radiographs ordered in patients with ankle injuries by one third. Field trials will assess the feasibility of implementing these rules into clinical practice. Other Formats: Links: Ann Emerg Med 1992 Apr;21(4):384-390 A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR Department of Emergency Medicine, Ottawa Civic Hospital, Ontario, Canada. STUDY OBJECTIVE: To develop decision rules that will predict fractures in patients with ankle injuries, thereby assisting clinicians in being more selective in their use of radiography. DESIGN: Prospective survey of emergency department patients over a five-month period. SETTING: Two university hospital EDs. PARTICIPANTS: One hundred fifty-five adults in a pilot stage and 750 in the main study; all presented with acute blunt ankle injuries. INTERVENTIONS: Thirty-two standardized clinical variables were assessed and recorded on data sheets by staff emergency physicians before radiography. MEASUREMENTS: Variables were assessed for reliability by the kappa coefficient and for association with significant fracture on both ankle and foot radiographic series by univariate analysis. The data then were analyzed by logistic regression and recursive partitioning techniques to develop decision rules for predicting fractures in each radiographic series. MAIN RESULTS: All 70 significant malleolar fractures found in the 689 ankle radiographic series performed were identified among people who had pain near the malleoli and were age 55 years or more, had localized bone tenderness of the posterior edge or tip of either malleolus, or were unable to bear weight both immediately after the injury and in the ED. This rule was 100% sensitive and 40.1% specific for detecting malleolar fractures and would allow a reduction of 36.0% of ankle radiographic series ordered. Similarly, all 32 significant midfoot fractures on the 230 foot radiographic series performed were found among patients with pain in the midfoot and bone tenderness at the base of the fifth metatarsal, the cuboid, or the navicular. CONCLUSION: Highly sensitive decision rules have been developed and will now be validated; these may permit clinicians to confidently reduce the number of radiographs ordered in patients with ankle injuries.