Emergency 2016; 4 (4): 188-191 OR I G I N A L RE S E A RC H Screening Characteristics of Ultrasonography in Detec- tion of Ankle Fractures Majid Shojaee1, Farhad Hakimzadeh1∗, Parisa Mohammadi1, Anita Sabzghabaei2, Mohammad Manouchehrifar2, Ali Arhami Dolatabadi1 1. Emergency Department, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2. Emergency Department, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Received: May 2015; Accepted: September 2015 Abstract: Introduction: Ankle fracture is one of the most common joint fractures. X-ray and physical examination are its main methods of diagnosis. Recently, ultrasonography (US) is considered as a simple and non-invasive method of fracture diagnosis. This study evaluated the diagnostic accuracy of US in detection of ankle fracture in com- parison to plain radiography. Methods: In this diagnostic accuracy study, which was done in emergency depart- ments of Imam Hossein and Shohadaye Tajrish hospitals, Tehran, Iran, during 2014, 141 patients with suspected diagnosis of distal leg or ankle fracture were examined by US and radiography (gold standard), independently. Screening performance characteristics of US in detection of distal leg fractures were calculated using SPSS ver- sion 21. Results: 141 patients with the mean age of 34 ± 11.52 years (range: 15–50) were evaluated (75.9% male). Radiography confirmed ankle fracture in 102 (72.3%) patients. There was a significant correlation between the results of US and radiography [Agreement: 95%; kappa: 0.88 (95% CI: 0.80–0.97); P < 0.001]. The screening per- formance characteristics of US in detection ankle fracture were as follows: sensitivity 98.9% (95% CI: 93.5% - 99.9%), specificity 86.4% (95% CI: 71.9%–94.3%), PPV 94.1% (95% CI: 87.1%–97.6%), NPV 97.4% (95% CI: 84.9%– 99.8%), PLR 16 (95% CI: 7.3–34.8), and NLR 0.02 (95% CI: 0.003 – 0.182). The area under the ROC curve of US in this regard was 95.8 (95% CI: 91.9 ± 99.7). Conclusion: According to the results of this study, we can use US as an accurate and non-invasive method with high sensitivity and specificity in diagnosis of malleolus fractures. However, the inherent limitations of US such as operator dependency should be considered in this regard. Keywords: Ankle fractures; radiography; ultrasonography; sensitivity and specificity © Copyright (2016) Shahid Beheshti University of Medical Sciences Cite this article as: Shojaee M, Hakimzadeh F, Mohammadi P, Sabzghabaei A, Manouchehrifar M, Arhami Dolatabadi A. Screening Charac- teristics of Ultrasonography in Detection of Ankle Fractures. Emergency. 2016; 4(4):188-191. 1. Introduction F oot and ankle fractures are known as the most com- mon traumatic injuries (1). Their incidence in men is three times more than in women, due to their physi- cal and potential differences (2–4). Motor vehicle crash and sport injuries are common causes of ankle fracture, espe- cially tibia fractures, in young people (5). A combination of clinical and radiographic findings is used for primary diag- nosis of the mentioned fractures (6). Ultrasonography (US) is considered as an available, economical, safe, and portable tool in fracture diagnosis. Using US can resolve problems ∗Corresponding Author: Farhad Hakimzadeh; Emergency Department, Imam Hossein Hospital, Shahid Madani Avenue, Imam Hossein Square, Tehran, Iran; Tel: +989123764779; Email: hakimzadehfarhad@yahoo.com. of other diagnostic tools such as radiation exposure, patient discomfort, and time investment (7). Barata et al. and Ek- inci et al. reported high sensitivity and specificity of US in detection of long bone fractures (8, 9). In addition, Esmailian et al. declared the accuracy of US in guidance and confir- mation of distal radius fractures reduction (10). Bianchi and his colleagues showed the valuable role of US in diagnosis of ankle’s stress fractures compared to magnetic resonance imaging (MRI) and radiography (11). Emergency medicine specialists are among the first line physicians responsible for management of multiple trauma patients. The accuracy of US performed by emergency physicians regarding detection of fractures is a matter of debate. Therefore, the present study aimed to evaluate the screening performance characteristics of US in detection of distal leg and ankle fractures in emer- gency setting. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: www.jemerg.com hakimzadehfarhad@yahoo.com 189 Emergency 2016; 4 (4): 189-191 2. Methods 2.1. Study Design The present diagnostic accuracy study was done in emer- gency departments of Imam Hossein and Shohadaye Tajr- ish Hospitals, Tehran, Iran, during 2014. The study aimed to compare the diagnostic value of US and radiography in patients with suspected traumatic ankle or distal leg frac- tures. The study was approved by the ethical committee of Shahid Beheshti University of Medical Sciences. The written informed consent was granted by all participants. 2.2. Participants 141 patients over 15 and under 50 years old, who were ad- mitted to the emergency department with traumatic ankle injuries, were consecutively included. All participants were suspected to have fractures of distal fibula and tibia as well as lateral and medial malleolus. The patients with hemo- dynamic instability, open fractures, and clear fracture diag- nosis due to major deformity were excluded. In addition, the patients who were manipulated by pre-hospital emer- gency medical service, or orthopedics were not enrolled in the study. No additional costs were imposed on the patients and the costs of procedures were covered by the authors themselves. 2.3. Intervention The US was performed by an emergency medicine resident, trained for about 10 hours in this regard under close super- vision of an expert emergency physician. After the primary and secondary surveys based on advanced trauma life sup- port guidelines (ATLS), the patients were examined by bed- side US followed by anterior-posterior, Lateral, and Mortis views ankle x-ray as the gold standard. All radiographs were reviewed and interpreted by one radiologist blinded to the clinical condition of patient. All US were performed us- ing SonoScape SSI-5500BW machine and linear 7.5–13 MHz probe in supine position. All procedures were performed under local or regional anesthesia using 0.2% lidocaine or a combination of 0.1 m g /k g intravenous midazolam and 1.5 µg /k g intravenous fentanyl. 2.4. Statistical Analysis Data were analyzed using SPSS 21 (SPSS, Chicago, IL, USA). Qualitative data were given as frequency and percentage, while quantitative data were reported as mean Âś standard deviation. Sensitivity, specificity, negative predictive value (NPV ), positive predictive value (PPV ), negative likelihood ratio (NLR), and positive likelihood ratio (PLR) were calcu- lated with 95% confidence intervals. Area under the receiver operating characteristic (ROC) curve of US in detection of an- kle fracture was calculated. P-value ≤ 0.05 was considered Table 1: Baseline characteristics of the patients Variable Number (%) Sex Male 105 (75.9) Female 34 (24.1) Side of injury Left 67 (47.5) Right 74 (52.5) Swelling Yes 115 (81.6) No 26 (18.4) Ecchymosis Yes 14 (9.9) No 127 (90.1) Ankle pain Yes 1 (0.7) No 140 (99.3) Ankle tenderness Yes 136 (96.5) No 5 (3.5) Type of trauma Direct trauma 20 (14.2) Strain/sprain 28 (19.9) Multiple trauma 93 (66) Mechanism of injury Motorcycle-car accident 22 (15.6) Pedestrian-car accident 28 (19.9) Falling 33 (23.4) Car-car accident 11 (27.8) statistically significant. 3. Results 141 patients with the mean age of 34±11.52 years (range: 15– 50) were evaluated (75.9% male). Baseline characteristics of the participants is summarized in table 1. Radiography con- firmed ankle fracture in 102 (72.3%) patients (53.9% internal and 46.1% external malleolus fracture). There was a signif- icant correlation between the results of US and radiography [Agreement: 95%; kappa: 0.88 (95% CI: 0.80–0.97); P < 0.001]. The screening performance characteristics of US in detec- tion ankle fracture were as follows: sensitivity 98.9% (95% CI: 93.5%–99.9%), specificity 86.4% (95% CI: 71.9%–94.3%), PPV 94.1% (95% CI: 87.1%–97.6%), NPV 97.4% (95% CI: 84.9%– 99.8%), PLR 16 (95% CI: 7.3–34.8), and NLR 0.02 (95% CI: 0.003–0.182). The area under the ROC curve of US in this re- gard was 95.8 (95% CI: 91.9 ± 99.7; figure 1). 4. Discussion The results of present study showed the acceptable accuracy of US in detection of ankle fracture. The sensitivity of 98.9% introduced the high screening value of US in this regard. In addition, PLR of 16 declared the ability of this test to increase This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: www.jemerg.com Shojaee et al. 190 Figure 1: Area under the receiver operating characteristic (ROC) curve of ultrasonography in detection of ankle fracture. the pre-test probability of ankle fracture, considerably. Although radiography has been considered as a readily avail- able and low-cost method for diagnosis of fractures for a long time, yet problems such as radiation exposure, quality of the image, and limitations for use in pregnant women have re- stricted its use. These problems double, when a fracture is present and imaging is needed for confirmation of closed reduction. In their systematic review and meta-analysis, Yousefifard et al. reported the pooled sensitivity and speci- ficity of US in detection of thoracic bone fractures to be 0.97 and 0.94, respectively (20). Since the use of US in emergency departments is increasing day by day, particularly for trauma patients, this study aimed to evaluate the accuracy of US in ankle fracture diagnosis. The value of US in diagnosing fractures was first introduced in 1980 and its high sensitivity and specificity has been re- ported in detection of long bones and wrist fractures (12– 17). Canagasabey et al. reported 90.9% sensitivity and speci- ficity of US in fracture diagnosis (17). Ekinci and his col- leagues supported the high accuracy of US by studying one hundred thirty one patients, reporting 100% sensitivity and 99.1% specificity (9). Trinh et al. showed 100% sensitivity and 88.9% specificity of US in detection of lateral malleolar in- juries in comparison with radiography (18). Atilla et.al stated the valuable screening characteristics of US in a study con- sisting of 246 patients with acute ankle sprain (19). In ad- dition to all the above-mentioned characteristics, we should consider the potential value of US in continuous monitoring of the fracture reduction process. Although we could not overlook the inherent limitations of US such as the high dependence of its accuracy on the op- erator’s skill. Yet, it can be useful in cases that radiography cannot be performed due to pregnancy, unstable hemody- namics, and inability to transfer the patient to the imaging unit. In addition, in some cases, verification of reductions with US can prevent the need for repeated radiography and more radiation exposure (10, 21). 5. Limitation Using plain radiography as a reference test, performance of US by emergency medicine residents instead of an expe- rienced emergency physician, not considering other ankle bone fractures such as talus fracture, and not considering the probable ankle joint dislocations, are among the most impor- tant limitations of the present study. More thorough studies in this field are suggested by considering more reliable tools such as computed tomography scan. 6. Conclusion The results of present study showed the acceptable accuracy of US in detection of ankle fracture. The sensitivity of 98.9% introduced the high screening value of US in this regard. In addition, PLR of 16 declared the ability of this test to increase the pre-test probability of ankle fracture, considerably. 7. Appendix 7.1. Acknowledgements The contribution of all trauma unit staff of Imam Hossein and Shohadaye Tajrish Hospitals is appreciated. This article is ex- tracted from the residency thesis of Farhad Hakimzadeh. 7.2. Author contribution All authors passed four criteria for authorship contribution based on recommendations of the International Committee of Medical Journal Editors. 7.3. Funding None. 7.4. Conflict of interest None. References 1. English E. Fractures and Soft Tissue Injuries of the Feet and Ankle. Canadian Family Physician. 1985;31:585. 2. McBirnie J. The epidemiology of tibial fractures. Journal of Bone & Joint Surgery, British Volume. 1995;77(3):417– 21. 3. Court-Brown C, Rimmer S, Prakash U, McQueen M. The epidemiology of open long bone fractures. Injury. 1998;29(7):529–34. 4. Court-Brown CM, Caesar B. Epidemiology of adult frac- tures: a review. Injury. 2006;37(8):691–7. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: www.jemerg.com 191 Emergency 2016; 4 (4): 191-191 5. 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