Eur J Trauma Emerg Surg (2013) 39:147–150 DOI 10.1007/s00068-012-0249-z
ORIGINAL ARTICLE
Ottawa versus Bernese: which is better? G. N. Beceren • S. Yolcu • O. Tomruk T. Atay • Y. B. Baykal
•
Received: 10 August 2011 / Accepted: 26 December 2012 / Published online: 11 January 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract Purpose Trauma of the foot and ankle is commonly seen in the emergency service. For most patients, fractures cannot be ruled out without radiography. The aim of this study is to consider these injured patients in the light of the Ottawa ankle rules and the Bernese ankle rules. Methods Our study is a randomized, prospective clinical study. This study was performed during a 24-month period in the Su¨leyman Demirel University Emergency Medicine Service. A total of 962 adult patients with foot and ankle pain or tenderness following trauma incurring within the previous 10 days were included in the study. Patients were examined only by physicians who had been trained in the
Our study was performed with the permission of Su¨leyman Demirel University Ethical Council, which works according to the 2000 Helsinki Declaration. G. N. Beceren (&) O. Tomruk Department of Emergency Medicine, Su¨leyman Demirel University Medical School, Isparta, Turkey e-mail:
[email protected];
[email protected] O. Tomruk e-mail:
[email protected] S. Yolcu Department of Emergency Medicine, Bozok University Medical School, Yozgat, Turkey e-mail:
[email protected] T. Atay Y. B. Baykal Department of Orthopedics and Traumatology, Su¨leyman Demirel University Medical School, Isparta, Turkey e-mail:
[email protected] Y. B. Baykal e-mail:
[email protected] correct application of the Ottawa ankle rules and the Bernese ankle rules. All patients were X-rayed with standardized anterior-posterior and lateral radiographs of the ankle and foot, regardless of whether the Ottawa ankle rules and the Bernese ankle rules were positive or negative. The sensitivity and specificity of the Ottawa and Bernese ankle rules according to the study results regarding the correlation between physical examination and radiography were calculated. Results For the Ottawa ankle rules, the sensitivity was 74.8 %, specificity was 68.6 %, false-negative ratio was 15.1 %, and the false-positive ratio was 46.3 %. For the Bernese ankle rules, the sensitivity was 55.7 %, specificity was 79 %, false-negative was ratio 21.4 %, and the false-positive ratio was 43.7 %. Conclusion These data suggest that the Ottawa ankle rules are more sensitive than the Bernese ankle rules to accurately identify the fracture, but they are still not 100 % reliable. Keywords Ottawa ankle rules Bernese ankle rules Trauma of ankle X-ray
Introduction Ankle injuries are one of the most common reasons for presenting to orthopedics and emergency departments [1]. However, although only a few of these patients—approximately 15 %—have a significant clinical fracture, radiography is performed in almost all patients, resulting in the lack of any positive diagnosis in 85 % of cases [2–7]. Ankle rules help to determine which patients with ankle injuries should undergo radiography [3, 6]. The most commonly used rules that have been designed to reduce the number of unnecessary radiographs ordered for these patients are the Ottawa ankle rules (OARs), which are based only on evaluating bone tenderness and clearly state that plain radiography is indicated if the patient is aged 55 years or more [2, 4].
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OARs examination areas: 1. 2. 3.
Bone tenderness along the distal 6 cm of the posterior edge of the tibia or tip of the medial malleolus, Bone tenderness along the distal 6 cm of the posterior edge of the fibula or tip of the lateral malleolus, An inability to bear weight both immediately and in the emergency department for four steps.
OARs sensitivity for detecting fractures of the ankle and midfoot region ranges from 94.6 to 100 % in the literature [5]. Very recently, a new indirect malleolar stress test called the Bernese ankle rules (BARs) has been developed by Eggli et al. Their clinical examination consists of three consecutive steps: indirect fibular stress, direct medial malleolar stress, and compression stress of the mid- and hindfoot [5]. The BARs’ three control zones are on the ankle. One is 10 cm proximally to the fibular tip, the second zone is the medial malleolus, and the last one is the mid- and hindfoot. The BARs examinations of these three areas are as follows: 1.
2. 3.
Indirect fibular stress: the malleolar fork is pressed flatly approximately 10 cm proximally to the fibular tip, Direct medial malleolar stress: compression is applied to the medial-lateral malleolus by thumb, Compression stress of the mid- and hindfoot: while the left hand immobilizes the calcaneus in the neutral position, the right hand pulls the forefoot, so that the mid- and hindfoot are pressed.
This new method provided a specificity of 91 % without missing a fracture and was more specific than the OARs [5]. In our search of the literature, we did not find any studies comparing the OARs with the newly produced BARs. Therefore, in this study, we tried to determine whether the BARs are more advantageous than the OARs in terms of specificity and sensitivity.
Patients and methods This is a prospective diagnostic study performed from January 2009 to December 2011 on patients presenting to the Emergency Department of Su¨leyman Demirel University Hospital aged 18 years and over with foot and ankle pain or tenderness following trauma incurred within the previous 10 days. Patients who were X-rayed outside our hospital, who were less than 18 years of age, who were pregnant, who had multiple traumas, and who had an isolated skin injury were excluded from study. A standard form was completed for each patient. This form included demographic data, mechanism of injury, and date of trauma. Each form also contained the OARs and the
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BARs. Patients were examined only by physicians who had been trained in the correct application of the OARs and the BARs. All questions and examinations were completed before radiographic examination (non-weight-bearing) and were completed on a standard form (Fig. 1). All patients were X-rayed using standardized anterior-posterior and lateral radiographs of the ankle and foot, regardless of whether the OARs and the BARs were positive or negative. Radiographic results were interpreted by an orthopedic surgery resident who had not examined the patients and, thus, was blind to the OARs and BARs diagnoses. All members of our study group signed the study form. Data were loaded into the SPSS 15 statistical program, the McNemar test for paired samples was used to test for significant differences between the rules, Spearman’s correlations were used to test for significant relations between the rules and radiography, and a p-value \ 0.01 was considered significant and used the receiver operating characteristic (ROC) curve test for sensitivity and specificity.
Results During the study period, 962 patients were examined. Those with a mean age of 30.3 ± 13.2 years (range 18–76 years) were included in the study. Most of the patients were male (581 males, 60.4 %), the most common injury mechanism was inversion injury (31.9 %) (Table 1), and the most common fracture type was a metatarsal fracture (16 %) (Table 2). After radiographic examination, 314 patients (32.6 %) were found to have fractures. While the OARs identified 235 of the 314 fractures, the BARs identified 175 fractures (Table 3). The ROC curve test showed that, for the OARs, the sensitivity was 74.8 %, specificity was 68.6 %, false-negative ratio was 15.1 %, and the false-positive ratio was 46.3 %. For the BARs, the sensitivity was 55.7 %, specificity was 79 %, false-negative ratio was 21.4 %, and the false-positive ratio was 43.7 %. The McNemar test showed a significant difference between the rules (p \ 0.001). According to Spearman’s test for fracture detection, there was a stronger and more positive correlation between the OARs and X-ray than between the BARs and X-ray (p \ 0.001, OARs r = 0.410, BARs r = 0.348). Spearman’s rho showed a significant correlation at the p \ 0.001 level. Several studies have been performed since 1981 to develop clinical decision-making rules for using radiographs in ankle injuries [2]. The OARs and BARs were designed to determine whether radiographic assessment is necessary to exclude
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Fig. 1 The standard form
Table 1 Distribution of trauma types
Table 2 Fracture types
Trauma type
Frequency
Percentage
Fracture type
Frequency
Percentage
Inversion injury
307
31.9
Eversion injury
271
28.2
Supination injury during walking Other
174 210
18.1 21.8
Total
962
100.0
No fracture Metatarsal fracture Lateral malleolus fracture Medial malleolus fracture Calcaneus fractures Total
648 154 82 34 44 962
67.4 16 8.5 3.5 4.6 100
fracture because, in North America, more than 5 million radiographs are ordered annually, at a cost of about 500 million US dollars [2].
Eggli et al. [5] found that 30 patients had false-positive clinical findings (8 %), resulting in a specificity of 91 % and demonstrating an 84 % reduction in the need for
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Table 3 Fractures identified with the Ottawa ankle rules (OARs) and the Bernese ankle rules (BARs) Bernese fractures No fracture
Total Medial malleolus fracture
Metatarsal fracture
Lateral malleolus fracture
Calcaneus fracture
Ottawa fractures No fracture
459
8
20
14
23
524
Medial malleolus fracture Metatarsal fracture
25 117
55 1
2 143
0 1
0 1
82 263
Lateral malleolus fracture
36
0
4
51
0
91
Calcaneus fracture Total
0
0
0
0
2
2
637
64
169
66
26
962
radiography. Stiell et al. showed that, if the physicians used the OARs, radiographs are less than 10 % because, under these rules, only two of 145 significant fractures were missed (sensitivity 99 %) [7]. According to Glas et al., the OARs identified 66 of the 74 fractures (sensitivity 89 % and specificity 26 %). In their study, they compared the OARs, Leiden ankle rules, and physicians’ judgment. The OARs missed eight fractures, of which one was clinically significant; the Leiden ankle rules missed 15 fractures, of which five were clinically significant; and the residents missed 13 fractures, of which one was clinically significant. They determined the OARs sensitivity to be 89 %, Leiden ankle rules 80 %, and the physicians’ judgment to be 82 % [3]. We were unable to find any research that applied both the OARs and the BARs to same patients group. Eggli et al. showed a new clinical test to examine the ankle and midfoot by applying forces to the injured region without direct compression of the bone. This was the first prospective Bernese study and they found a sensitivity of 100 % and a specificity of 91 %, without missing a fracture [5]. In our study, we determined that the OARs identified 235 of the 314 fractures (sensitivity 74.8 %) and the BARs identified 175 fractures (sensitivity 55.7 %). One of the weak points of the OARs is the low specificity of the test, which leads to many false-positive clinical findings [5], like in our study. In our study, the OARs falsepositive ratio was found to be 46.3 %. A small number of previous studies have compared ankle rules or guidelines with physicians’ performance, similar to the research involving the comparison of the OARs and the BARs. For this reason, we aimed to determine to which rules are more sensitive to identifying the fractures, further reducing the use of radiography. Thus, patients are more satisfied if they do not have to go under radiography [2].
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Conclusion In our study, the diagnostic performance of residents using structured data collection was compared with two sets of ankle rules for patients with acute ankle injury. McNemar tests showed a significant difference between the two rules: the Ottawa rules identified more fractures than the Bernese rules. However, even thought the patient’s clinical and physical examinations are important, our study suggests using the ankle rules during the radiography decision process. This study also shows that these rules are suitable for helping to determine which patients with ankle injuries should undergo radiography. Conflict of interest
None.
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