Validation of the Ottawa Ankle Rules in Iran: A prospective survey
© Yazdani et al; licensee BioMed Central Ltd. 2006
Received: 14 July 2005
Accepted: 16 February 2006
Published: 16 February 2006
Acute ankle injuries are one of the most common reasons for presenting to emergency departments, but only a small percentage of patients – approximately 15% – have clinically significant fractures. However, these patients are almost always referred for radiography. The Ottawa Ankle Rules (OARs) have been designed to reduce the number of unnecessary radiographs ordered for these patients. The objective of this study was to validate the OARs in the Iranian population.
This prospective survey was done among 200 patients with acute ankle injury from January 2004 to April 2004 in the Akhtar Orthopedics Hospital Emergency Department. Main outcome measures of this survey were: sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios (positive and negative) of the OARs.
Sensitivity of the OARs for detecting 37 ankle fractures (23 in the malleolar zone and 14 in the midfoot zone) was 100% for each of the two zones, and 100% for both zones. Specificity of the OARs for detecting fractures was 40.50% for both zones, 40.50% for the malleolar zone, and 56.00% for the midfoot zone. Implementation of the OARs had the potential for reducing radiographs by 33%.
OARs are very accurate and highly sensitive tools for detecting ankle fractures. Implementation of these rules would lead to significant reduction in the number of radiographs, costs, radiation exposure and waiting times in emergency departments.
Scientific reports about clinical decision rules are increasingly published in medical literature. These rules (a) are decisional tools resulting from research projects rather than consensus-based clinical practice guidelines; (b) are coordinated results of three or more variables in clinical history, physical examination and simple tests; and (c) are used in determining the diagnosis, prognosis and possible responses in each individual patient. These tools help the physician to effectively challenge his/her uncertainty in clinical decision-making. In addition, using these rules can enhance the physician's efficiency, which is a must in the current situation where health care systems are increasingly calling for more cost-effective methods in clinical practice .
There have been several attempts to validate the OARs in different countries [12–21]. In their systematic review, Bachman et al  showed that the sensitivity of The OARs range from 96.4% (95% confidence interval: 93.8–98.6%) in some studies to 99.6% (95% confidence interval: 98.2–100%) in others. Also, specificity ranges from 47.9% (interquartile range: 42.3–77.1%) to 26.3% (19.4–34.3%).
Despite these successful results, however, there are other studies that could not validate the OARs [23–25]. In addition, since no specific standard is used for the diagnosis and treatment of ankle injuries in Iran – especially in public teaching hospitals – it appears that there is a tendency toward "defensive medicine" among physicians. Therefore, in view of the high prevalence of ankle injuries as well as difficulties experienced in the current trend of radiography requisitions, and considering the unique features of the OARs, validation of these rules in an Iranian population has been evaluated.
This prospective study was performed in a 3-month period from January-April 2004 on 237 patients presenting to Akhtar Orthopedics Hospital Emergency Department with ankle pain or tenderness following a blunt trauma. The definitions of ankle zones based on Steill studies are as follows:
1. Malleolar zone: 6 cm of the distal fibula and tibia as well as the talus bone
2. Midfoot zone: Navicular, cuboid, cuneiforms, anterior process of calcaneus and the base of the fifth metatarsal bone.
Patients who were less than 16 years of age or pregnant, those with injuries of more than seven days, those referring for re-evaluation, and those with multiple trauma or decreased level of consciousness were excluded from study.
Patients were physically examined and evaluated regarding the 8 clinical variables included in the OARs. Each patient's data was recorded and coded. All patients were referred for standard radiography of the malleolar zone, midfoot zone or both according to the presence of pain or tenderness in one or both of these zones. Radiography results were interpreted by an orthopedics surgery resident who had not visited or examined the patients.
For statistical analysis, SPSS for Windows V. 10.0 was used. Sensitivity, specificity, positive and negative likelihood ratio, and positive and negative predictive value with a 95% confidence interval were calculated.
Age mean(SD), year
Mechanism of injury
Falling in pot-holes
twisting ankle during casual walking
Tripping over obstacles
Time of Arrival to Emergency
Base of 5th metatarsal
Short leg splint
Short leg cast
Types of treatment performed on ankle injury patients
Type of injury
Type of treatment
Short leg splint
Short leg cast
Fracture (N = 37)
Ligamentous (N = 163)
Rate of injuries and conformity of the OARs results with diagnostic feature
Concomitant injury in both zones
Causing mechanisms for injuries included sport activities (49 patients, 24.5%), descending stairs (31 patients, 15.5%), falling in pot-holes (25 patients, 12.5%), twisting ankle during casual walking (20 patients, 10%), direct trauma (17 patients, 8.5%), falling down (16 patients, 8%), tripping over obstacles (13 patients, 5.6%) and others (29 patients, 14.5%).
Of this number, 37 cases (18.5%) had fractures, of which 23 cases (62.16%) were in the malleolar zone and 14 cases (37.84%) in the midfoot zone. Therapeutic interventions included short leg splint (111 patients, 55.50%), short leg cast (42 patients, 21.00%), conservative management (38 patients, 19.00%), surgical operation (5 patients, 2.5%) and others (4 patients, 2.00%).
As shown in Table 3, the OARs sensitivity in detecting fractures was 100% (95% CI: 85.30–100%) for those with isolated malleolar injuries (142 patients, 21 fractures), 100% (95% CI: 73.33–100%) for isolated midfoot injuries (37 patients, 12 fractures), and 100% (95% CI: 32–100%) for concomitant fracture of both zones (21 patients, 4 fractures). The sensitivity of the OARs was also calculated to be 100% (95% CI: 91.82–100%) in overall evaluation (200 patients, 37 fractures).
The overall specificity, specificity for the malleolar zone, the midfoot zone and injuries to both zones were 40.50% (95% CI: 32.87–48.11%), 40.50% (95% CI: 31.62–49.37%), 56.00% (95% CI: 35.09–76.91%), and 17.65%, respectively. Negative predictive values for malleolar, midfoot and overall rate of fractures were 100% (95% CI: 93.86–100%), 100% (95% CI: 77.43–100%), and 100% (95% CI: 95.46–100%), respectively. Negative likelihood ratio was nil for all three evaluations.
The positive predictive value of the OARs was 22.58% (95% CI: 13.92–22.58%) for malleolar zone fractures, 52.17% (95% CI: 30.09–74.26%) for midfoot fractures and 27.61% (95% CI: 19.94–35.28%) in overall evaluation. The positive likelihood ratio was 1.68, 2.27 and 1.68 for the malleolar zone, the midfoot zone and the overall evaluation, respectively.
Negative predictive value, negative likelihood ratio, positive predictive value and positive likelihood ratio for concomitant injuries were calculated to be 100%, 0, 22.22% and 1.21, respectively.
The OARs were designed, reviewed and validated by its Canadian inventors, and used in various clinical settings. Their simplicity in application and memorization  has made them a very powerful tool to decrease radiology department referrals and to save cost and time. In addition, these rules have been successfully and favorably validated in the US, the UK, France, the Netherlands, Greece, Spain, Australia and Hong Kong.
Without validation, however, even well defined decision-making rules are not suitable for application in all clinical settings, for three reasons. First, predictive rules resulting from a study on a patient population may only demonstrate an accidental relation between presumed predictive factors and outcomes. Thus, there may be a quite different set of predictive factors in other groups of patients.
Second, the relations between predictive factors and the population under study, physicians using the rules or other aspects of study design, may have unique and specific features. This may also invalidate clinical decision-making rules in new circumstances.
Third, physicians may not be able to use decision-making rules comprehensively or perfectly because of some feasibility problems in a specific clinical setting. Therefore, all decision-making rules need to be validated.
Moreover, some study results [23–25] have rejected the generalizablity of the OARs, although these studies had considerable methodological errors or did not use real rules [28, 29]. Therefore, considering the differences in human populations and also in physicians' behavior, validation of the OARs was considered in this study.
Traditionally, immobilization, functional treatment – i.e., an early mobilization protocol with the use of external support – and surgical treatment are three main treatments for acute lateral ankle ligament ruptures. However, in several reviews, functional treatment and early mobilization – especially with lace-up supports- have been preferred to immobilization in a cast or surgical operation . Since our results showed that cast and splint are still used for the treatment of ligamentous injuries, it seems necessary to take effective action in modifying this improper trend.
It is estimated that more than 5 million radiographs are ordered annually in Northern America, costing about 500 million US dollars. It must be noted that multiple low-cost tests such as plain radiographs can be as much a financial burden to health system as high-tech, high-cost but fewer medical interventions . In addition, patients are more satisfied if they do not have to go under radiography .
According to the present study, of about 70 patients presenting each day to the Akhtar Orthopedics Hospital Emergency Department, approximately 20% have ankle injuries. Thus, of a roughly estimated 25,500 presentations each year, 5100 are only for ankle injuries. Based on the tariffs confirmed by the Iranian Ministry of Health for public hospital services, anterior-posterior and lateral radiographs of the ankle zone cost about 24000 Rls (2.80 US dollars), while the cost for a radiograph of the foot zone is 26600 Rls (3.10 US dollars). Moreover, in most ankle injuries, both radiographs are ordered. If only 33% of radiographs could be avoided by using the OARs, savings would reach up to 85,200,000 Rls (more than 10000 US dollars) each year (while the official fee for a general practitioner visit is 14400 Rls [1.70 US dollars], this would be a considerable amount). Also, we should add to this figure the indirect costs saved by reducing the time patients spend in the hospital. It is obvious how enormous the savings would be if these decision-making rules were to be used at the level of a medical university or an entire country. These savings seem to be most needed in developing countries such as Iran.
OARs application, however, has some limitations and obstacles. Would all emergency physicians agree to treat their patients without taking a radiograph? Would they take the legal responsibility in case of a possible fracture?
Some studies showed that even after attending a one-hour training program on the OARs and despite having a very good opinion towards the subject, physicians did not use the OARs . In addition, the rate of radiograph reduction in current practice may not be as anticipated. This could be due to the patients' anxiety or the physicians' obsessiveness to order radiographs even when the required criteria are not met.
It should also be noted that currently, patients might not all accept the physician's avoidance from ordering a radiograph for ankle injuries, and think of it as the doctor's lack of knowledge or ignorance. Unfortunately, there is a widespread tendency among patients to use various diagnostic tools. This is also one of the challenges for using such rules.
The current study faced some limitations. The relatively low number of cases made it difficult to generalize the results to other medical centers and the entire Iranian population. In addition, because we did not have any case of calcaneus, talus, navicular or cuboid fractures, the achieved results may not be perfect in view of all fractures in this zone. Inter-observer reliability among different groups -attending physicians, residents, and interns- was also not determined.
Referring all patients for radiography and the subsequent danger of radiation exposure was not an ethical problem, because it is currently the routine procedure performed for all patients.
Our study proved that the OARs have the same results in the Iranian population as in the original study and the majority of other investigations. The sensitivity of these rules was 100% for diagnosing ankle and midfoot fractures, and application of these rules significantly reduced the number of radiographs by approximately 33%. Thus, OARs application can not only decrease the number of radiology department referrals, but also can reduce costs and radiation exposure and save time for hospital staff and patients
Suggestions for further evaluation include assessing the OARs' validity with more samples; assessing the OARs' validity in different medical centers, populations and by various treatment staff with different levels of clinical skill and expertise; studying physicians' attitude about and acceptance of these rules in the clinic setting; evaluating real changes resulting from application of the OARs; and evaluating patients' and physicians' satisfaction in case of using the OARs or other such rules.
Statistical characteristics of Ottawa Ankle Rules
Concomitant injuries of both zones
The authors consider their duty to give their very special thanks to Dr. Mohsen Ghofrani, Mr. Sina Rahmati, and Dr. Mehdi Firouzabadi for their kind cooperation.
- Brand DA, Frazier WH, Kohlhepp WC, Shea KM, Hoefer AM, Ecker MD, Kornguth PJ, Pais MJ, Light TR: A protocol for selecting patients with injured extremities who need x-rays. N Engl J Med. 1982, 306: 333-339.View ArticlePubMedGoogle Scholar
- Stiell IG, McDowell I, Nair RC, Aeta H, Greenberg G, McKnight RD, Ahuja J: Use of radiography in acute ankle injuries: physicians' attitudes and practice. Can Med Assoc J. 1992, 147: 1671-1678.Google Scholar
- Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, Stewart JP, Maloney J: Decision rules for the use of radiography in acute ankle injuries: refinement and prospective validation. JAMA. 1993, 269: 1127-1132. 10.1001/jama.269.9.1127.View ArticlePubMedGoogle Scholar
- Stiell IG, McKnight RD, Greenberg GH, McDowell I, Nair RC, Wells GA, Johns C, Worthington JR: Implementation of the Ottawa ankle rules. JAMA. 1994, 271: 827-832. 10.1001/jama.271.11.827.View ArticlePubMedGoogle Scholar
- Brandser EA, Berbaum KS, Dorfman DD, Braksiek RJ, El-Khoury GY, Saltzman CL, Marsh JL, Clarck WA: Contribution of Individual Projections Alone and in Combination for Radiographic Detection of Ankle Fractures. Am J Roentgenol. 2000, 174: 1691-1697.View ArticleGoogle Scholar
- Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR: A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992, 21: 384-390. 10.1016/S0196-0644(05)82656-3.View ArticlePubMedGoogle Scholar
- Stiell IG, McKnight RD, Greenberg GH, Nair RC, McDowell I, Wallace GJ: Interobserver agreement in the examination of acute ankle injury patients. Am J Emerg Med. 1992, 10: 14-17. 10.1016/0735-6757(92)90117-G.View ArticlePubMedGoogle Scholar
- Wasson JH, Sox HC, Neff RK, Goldman L: Clinical prediction rules: application and methodological standards. N Engl J Med. 1985, 313: 793-799.View ArticlePubMedGoogle Scholar
- Lee TH: Evaluating decision aids: the next painful step. J Gen Intern Med. 1990, 5: 528-529.View ArticlePubMedGoogle Scholar
- Stiell I, Wells G, Laupacis A, Brison R, Verbeek R, Vandemheen K, Naylor D: A multicentre trial to introduce clinical decision rules for the use of radiography in acute ankle injuries. BMJ. 1995, 311: 594-597.View ArticlePubMedPubMed CentralGoogle Scholar
- Stiell IG, Wells GA: Methodologic standards for development of clinical decision rules in emergency medicine. Ann Emerg Med. 1999, 33: 437-447. 10.1016/S0196-0644(99)70309-4.View ArticlePubMedGoogle Scholar
- McBride KL: Validation of the Ottawa ankle rules: Experience at a community hospital. Can Fam Physician. 1997, 43: 459-465.PubMedPubMed CentralGoogle Scholar
- Auleley GR, Kerboull L, Durieux P, Cosquer M, Courpied JP, Ravaud P: Validation of the Ottawa ankle rules in France: a study in the surgical emergency department of a teaching hospital. Ann Emerg Med. 1998, 32 (1): 14-18. 10.1016/S0196-0644(98)70093-9.View ArticlePubMedGoogle Scholar
- Leddy JJ, Smolinski RJ, Lawrence J, Snyder JL, Priore RL: Prospective evaluation of the Ottawa Ankle Rules in a university sports medicine center with a modification to increase specificity for identifying malleolar fractures. Am J Sports Med. 1998, 26: 158-165.PubMedGoogle Scholar
- Markert RJ, Walley ME, Guttman TG, Mehta R: A pooled analysis of the Ottawa ankle rules used on adults in the ED. Am J Emerg Med. 1998, 16 (6): 564-567. 10.1016/S0735-6757(98)90219-4.View ArticlePubMedGoogle Scholar
- Aginaga Badiola JR, Ventura Huarte I, Tejera Torroja E, Huarte Sanz I, Cuende Garces A, Gomez Garceran M, Labaca Arteaga J: [Validation of the Ottawa ankle rules for the efficient utilization of radiographies in acute lesions of the ankle]. Atencion Primaria. 24 (4): 203-208. 1999 Sep 15Google Scholar
- Yuen MC, Sim SW, Lam HS, Tung WK: Validation of the Ottawa ankle rules in a Hong Kong ED. Am J Emerg Med. 2001, 19 (5): 429-432. 10.1053/ajem.2001.24474.View ArticlePubMedGoogle Scholar
- Papacostas E, Malliaropoulos N, Papadopoulos A, Liouliakis C: Validation of Ottawa ankle rules protocol in Greek athletes: study in the emergency departments of a district general hospital and a sports injuries clinic. Br J Sports Med. 2001, 35 (6): 445-447. 10.1136/bjsm.35.6.445.View ArticlePubMedPubMed CentralGoogle Scholar
- Pijnenburg AC, Glas AS, De Roos MA, Bogaard K, Lijmer JG, Bossuyt PM, Butzelaar RM, Keeman JN: Radiography in acute ankle injuries: the Ottawa Ankle Rules versus local diagnostic decision rules. Ann Emerg Med. 2002, 39 (6): 599-604. 10.1067/mem.2002.121397.View ArticlePubMedGoogle Scholar
- Wynn-Thomas S, Love T, McLeod D, Vernall S, Kljakovic M, Dowell A, Durham J: The Ottawa ankle rules for the use of diagnostic X-ray in after hours medical centres in New Zealand. N Z Med J. 115 (1162): U184-2002 Sep 27Google Scholar
- Broomhead A, Stuart P: Validation of the Ottawa Ankle Rules in Australia. Emerg Med (Fremantle). 2003, 15 (2): 126-132.View ArticleGoogle Scholar
- Bachmann LM, Kolb E, Koller MT, Steurer J, Riet GL: Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. BMJ. 2003, 326: 417-10.1136/bmj.326.7386.417.View ArticlePubMedPubMed CentralGoogle Scholar
- Lucchesi GM, Jackson RE, Peacock WF, Cerasani C, Swor RA: Sensitivity of the Ottawa rules. Ann Emerg Med. 1995, 26 (1): 1-5. 10.1016/S0196-0644(95)70229-6.View ArticlePubMedGoogle Scholar
- Tay SY, Thoo FL, Sitoh YY, Seow E, Wong HP: The Ottawa Ankle Rules in Asia: validating a clinical decision rule for requesting X-rays in twisting ankle and foot injuries. J Emerg Med. 1999, 17 (6): 945-947. 10.1016/S0736-4679(99)00120-1.View ArticlePubMedGoogle Scholar
- Perry S, Raby N, Grant PT: Prospective survey to verify the Ottawa ankle rules. J Accid Emerg Med. 1999, 16: 258-260.View ArticlePubMedPubMed CentralGoogle Scholar
- Bondolier. [http://www.jr2.ox.ac.uk/bandolier/band21/b21-5.html]
- McGinn T, Guyatt G, Wyer P, Naylor CD, Stiell I: Diagnosis: clinical prediction rules. User's guides to the medical literature. Edited by: Guyatt G, Rennie D. 2002, Chicago: AMA Press, 471-484.Google Scholar
- Stiell IG, Greenberg GH, McKnight RD, Wells GA: The "real" Ottawa Ankle Rules. Ann Emerg Med. 1996, 27: 103-104. 10.1016/S0196-0644(96)70309-8.View ArticlePubMedGoogle Scholar
- Stiell IG, Greenberg GH, McKnight RD, Wells GA: Ottawa Ankle Rules for radiography of acute ankle injuries. N Z Med J. 1995, 108: 111-PubMedGoogle Scholar
- Kerkhoffs GM, Struijs PA, Marti RK, Blankevoort L, Assendelft WJ, van Dijk CN: Functional treatments for acute ruptures of the lateral ankle ligament: a systematic review. Acta Orthop Scand. 2003, 74 (1): 69-77. 10.1080/00016470310013699.View ArticlePubMedGoogle Scholar
- Angell M: Cost containment and the physician. JAMA. 1985, 254: 1203-1207. 10.1001/jama.254.9.1203.View ArticlePubMedGoogle Scholar
- Cameron C, Naylor CD: No impact from active dissemination of the Ottawa Ankle Rules: further evidence of the need for local implementation of practice guidelines. Can Med Assoc J. 1999, 160: 1165-1168.Google Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-227X/6/3/prepub
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