Archives of Academic Emergency Medicine. 2019; 7 (1): e21 OR I G I N A L RE S E A RC H Quebec Decision Rule in Determining the Need for Radio- graphy in Reduction of Shoulder Dislocation; a Diagnostic Accuracy Study Ehsan Bolvardi1, Behnaz Alizadeh1, Mahdi Foroughian1, Bita Abbasi2, Seyed Reza Habibzadeh1, Reza Akhavan1∗ 1. Department of Emergency Medicine, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran. 2. Department of Radiology, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran. Received: November 2018; Accepted: December 2018; Published online: 25 February 2019 Abstract: Introduction: The Quebec Decision Rule (QDR) has been developed for deciding on the necessity of radiogra- phy for patients with shoulder dislocation. This study aimed to investigate the diagnostic value of QDR in this regard. Methods: This diagnostic accuracy study was conducted on patients with shoulder dislocation visiting the emergency department. After filling out the QDR-based checklist for all patients, they underwent radiogra- phy and the obtained radiography results were compared to QDR-based clinical diagnostic findings. Results: 143 patients with the mean age of 32.1 ± 12 years were evaluated (88.8% males). Sensitivity, specificity, and pos- itive and negative predictive values of QDR were 50%, 58.2%, 3.3%, and 97.6%, respectively. The sensitivity and specificity were 100% and 50% in patients > 40 years old, and 33.3% and 59.8% in those < 40 years old. These indices were 33.3% and 60.4%, respectively, in the male sex and 100% and 40% in the female sex. Conclusion: Quebec decision rule holds promise to diagnose concomitant fractures in patients over the age of 40 with 100% sensitivity, thereby reducing the number of radiographies by 50% without causing diagnostic errors. In contrast, this criterion proved inefficient in patients younger than 40. Keywords: Quebec; shoulder dislocation; decision support techniques; diagnostic imaging; radiography Cite this article as: Bolvardi E, Alizadeh B, Foroughian M, Abbasi B, Habibzadeh S R, Akhavan R. Quebec Decision Rule in Determining the Need for Radiography in Reduction of Shoulder Dislocation; a Diagnostic Accuracy Study. Arch Acad Emerg Med. 2019; 7(1): e21. 1. Introduction Shoulder dislocation is the most common type of joint dis- location in humans with the prevalence of 17-23 cases per each 100,000 population (1-3). Closed-reduction is usually a successful initial treatment for anterior shoulder disloca- tion (4). In the majority of cases, pre- and post-reduction radiography are advocated to confirm dislocation and en- sure the complete reduction and evaluation for fractures (5). Current studies have questioned the need for pre- and post- reduction radiographs in shoulder dislocation (5-7). Accord- ing to researchers’ findings, radiographs are needed to con- firm the location of the reduced joint in dislocations with an associated fracture or when the physician is uncertain ∗Corresponding Author: Reza Akhavan; Department of Emergency Medicine, Faculty of Medicine, Mashhad University of Medical sciences, Mashhad, Iran. Tel: 05138525312; Email: Akhavanr@mums.ac.ir (8). The Quebec Shoulder Dislocation (QSD) Rule is a clini- cal decision-making guideline, designed by a group of Cana- dian researchers, to guide physicians about the indications of radiography in patients with a shoulder dislocation. This guideline advocates the use of pre-reduction radiography in adult patients younger than 40 years if the mechanism of in- jury involves a motor vehicle collision, a fall from standing height, or a sports injury. In young people, these guidelines have a sensitivity of 100% and a negative predictive value of 99.2% in diagnosis of clinically important fractures and can reduce the number of pre-reduction radiographies by 27.9% (9). Nevertheless, all of these findings were not confirmed by all subsequent studies. Although these findings indicate that pre- and post-reduction radiography are not needed for all patients with shoulder dislocation, there is still no stan- dard, reliable, generally applicable, and broadly accepted technique. Since the pre- and post-reduction radiography processes are significantly time-consuming and expose the patients to harmful radiation and impose a huge financial This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem E. Bolvardi et al. 2 burden on them and the healthcare system, this study in- tended to investigate the diagnostic value of this guideline in patients with shoulder dislocation, visiting emergency de- partment. 2. Methods 2.1. Study design and setting This cross-sectional (diagnostic accuracy) study was con- ducted on patients with shoulder dislocation visiting Imam Reza and Shahid Hasheminejad Hospitals of Mash- had, Iran, between December 2016 and December 2017. This project was approved by the Ethics Committee of Mashhad University of Medical Sciences under the code IR.MUMS.fm.REC.1394.599. Researches adhered to princi- ples of Helsinki declaration and confidentiality of patients’ information during the study period. 2.2. Participants All patients who presented to the emergency departments of the mentioned hospitals during the study period were en- rolled without any gender limitation using the convenience sampling technique. Patients less than 18 years old, as well as patients with neural or vascular injuries in the affected or- gan were excluded. 2.3. Data gathering A checklist containing the baseline characteristics of the pa- tients as well as QDR variables was designed for data gather- ing. After obtaining informed consent from the participants, the QDR-based designed checklist was completed for all par- ticipants. Then standard digital radiography (AP-lateral-Y view) was performed. If the radiographs confirmed disloca- tion, shoulder reduction would be carried out after proce- dural sedation and analgesia based on the existing depart- ment protocol (Fentanyl 1micro/kg + propofol 1mg/kg). Fi- nally, results of QDR criteria regarding the need for imaging were compared to radiographs and its sensitivity, specificity, and negative and positive predictive values were calculated. Data Gathering and examinations were performed by emer- gency medicine physicians. All radiographs were interpreted by two emergency medicine physicians and a radiologist was consulted whenever there were disagreements or diagnostic uncertainties. According to QDR, pre-reduction radiography is necessary for adult patients younger than 40 if the injury involves a motor vehicle collision, fight, a fall from standing height, or sports injury. QDR also recommends radiography for pa- tients under 40 with and without ecchymosis who have their first-time shoulder dislocation (10). 2.4. Statistical Analysis The required sample size estimation was 140 patients based on the confidence interval of 95% and accuracy of 12% (10). The controlled data was fed into SPSS 12 and analyzed using tables, diagrams, and central and distribution indices. Find- ings were reported using mean ± standard deviation or fre- quency and percentage. P<0.05 was considered statistically significant. Student’s t-test and chi square test were used for comparing the two groups regarding quantitative and quali- tative variables, respectively. The diagnostic values including sensitivity, specificity, positive and negative predictive val- ues, and positive and negative likelihood ratios were reported with 95% confidence interval. 3. Results 3.1. Baseline characteristics of studied patients 143 patients with the mean age of 32.1 ± 12 (8 – 74) years were studied (88.8% male). The patients’ baseline charac- teristics, major causes of dislocation, side of dislocation, and pre-reduction radiographic findings are presented in table 1. Patients < 40 and > 40 years old were similar regarding the baseline characteristics. Patients <40 years old had a signifi- cantly higher rate of recurrent dislocation (4.9 ± 6.2 vs 1.5 ± 0.5 times; p < 0.001). 3.2. Diagnostic accuracy of QDR According to QDR criteria, there was an indication for pre- reduction radiography in 60 (42%) patients. Two out of four patients (50%) with concomitant fractures had radiography indication based on QDR. The overall screening performance characteristics of QDR based on gender and age are pre- sented in table 2. Quebec decision rule has an excellent sen- sitivity in patients older than 40 years, and also in females (both 100%). The observed positive likelihood ratio (LR+) for QDR criteria was 1.19 and the negative likelihood ratio (LR-) was 0.85 for the whole study population. However, the high- est LR+ for this test belonged to patients older than 40 years and females. 4. Discussion Based on the QDR criteria, pre-reduction radiography was indicated in 42% of the study subjects. The sensitivities and specificities of QDR in diagnosis of concomitant fracture and need for pre-reduction were 50% and 58.2%, respectively. Ap- plication of QDR can reduce the number of radiographies by 56%. Since pre- and post-reduction radiographies seem un- necessary for all patients with shoulder dislocation, a guide- line for indication of radiography is needed in these patients. QDR is among the most important attempts made in this re- gard (10). Based on one study, in young people, QDR guide- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 3 Archives of Academic Emergency Medicine. 2019; 7 (1): e21 Table 1: Baseline characteristics of the study population Variables Age (years) P value < 40 (n=120) > 40 (n=23) Gender Male 110 (91.7) 17 (73.9) 0.24 Female 10(8.3) 6(26.1) Type of dislocation Anterior 117 (97.5) 23 (100) >0.99 Posterior 3 (2.5) 0 (0) Side of dislocation Right 92 (76.7) 19 (82.6) 0.78 Left 28 (23.3) 4 (17.4) Mechanism of dislocation Motor vehicle collision 13 (10.8) 0 (0) Fights 8 (6.7) 0 (0) Falling 14 (11.7) 15 (65.2) N/A Exercise 16 (13.3) 0 (0) Other 69 (57.5) 8 (34.8) Clinical signs Ecchymosis 3 (2.5) 0 (0) >0.99 None 117 (97.5) 23 (100) Pre-reduction X-ray Normal 117 (97.5) 22 (95.7) 0.508 Fracture 3 (2.5) 1 (4.3) Post-reduction X-ray Normal 117 (100) 22 (100) N/A Abnormal 0 (0) 0 (0) Need for imaging (QDR) Indicated 48 (40.0) 12 (52.2) 0.357 Not indicated 72 (60.0) 11 (47.8) Data are presented as frequency (%). QDR: Quebec decision rule. Table 2: Screening performance characteristics of Quebec decision rule in patients with shoulder dislocation Total > 40 years < 40 years Male Female Sen 50.0(6.7-93.2) 100(2.5-100) 33.3(0.8-90.6) 33.3(0.8-90.6) 100(2.5-100) Spec 58.2(49.6-66.6) 50(28.2-71.8) 59.8(50.4-66.8) 60.4(51.3-69.1) 40(16.3-67.7) PPV 3.3(1.3-8.6) 8.3(5.6-12.1) 2(0.4-9.7) 2(0.4-9.3) 10(6.8-30.2) NPV 97.6(93.7-99.0) 100(N/A) 97.2(93.9-98.7) 97.4(94.3-98.8) 100(N/A) LR+ 1.19(0.44-3.25) 2(1.31-3.03) 0.83(0.16-4.17) 0.84(0.16-4.24) 1.66(1.10-2.51) LR- 0.85(0.31-2.30) 0(N/A) 1.11(0.49-2.51) 1.10(0.48-2.48) 0(N/A) Data are presented with 95% confidence interval. Sen: Sensitivity; Spec: Specificity; PPV: Positive predictive value; NPV: Negative predictive value; LR+: Positive likelihood ratio; LR-: Negative likelihood ratio. N/A: not applicable. line has a sensitivity of 100% and a negative predictive value of 99.2% in diagnosis of clinically important fractures and can reduce the number of pre-reduction radiographies by 27.9% (10). Nevertheless, studies still cannot absolutely con- firm or deny its efficiency in evaluation of shoulder dislo- cation. Clinical evidence can lead experienced emergency medicine physicians to diagnosis of anterior shoulder dis- location and eliminate radiographies before reduction (11, 12). It has been reported that although 37% of fractures were observed in post-reduction radiographs, none of the missed cases affected the treatment outcome. Accordingly, although shoulder dislocation is likely to be associated with fractures, which may be missed in the initial radiographs because of their small size or joint position, they do not necessitate a dif- ferent treatment process (13). Three important factors that correlated with fracture were age greater than 40 years, no prior dislocation, and injury mechanism. Accordingly, shoulder radiography is advocated for cases with a first-time dislocation, traumatic mechanism, and when the physician is uncertain of joint position. This algorithm reduced the number of radiographies by 46% and resulted in significant savings in time in a previous study. On the other hand, no missed fracture or dislocation was ob- served in cases without shoulder radiography (14). There are This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem E. Bolvardi et al. 4 some similar studies on the sensitivity and accuracy of QDR criteria. For example, Emond et al. (10) investigated the sen- sitivity and specificity of QDR criteria and found 100% sensi- tivity and 34.2% specificity, and a negative predictive value of 99.2%. The use of this criterion reduced the use of pre- and post-reduction radiographies by 27.9% and 81.9%, respec- tively. Abuye et al. (15) also investigated QDR and showed that this algorithm could reduce the number of radiographies by 50%. The researchers concluded that injury mechanism and recurrent dislocation are two important factors to deter- mine whether pre-reduction radiography is needed. These findings are completely consistent with our findings. Due to a significant difference in the mechanism of disloca- tion and the prevalence of associated fracture by age, we in- vestigated the efficiency of QDR in two specific age groups (older and younger than 40). Results suggested a higher sen- sitivity and negative predictive value in patients older than 40 years. Ong et al. studied 196 patients under 40 and found that 59% of them were at high risk according to QDR. In to- tal, 12 (6%) fracture cases were observed. Accordingly, QDR reached a sensitivity of 42%, a specificity of 40%, and a pre- dictive value of 91% for associated fracture evaluation in such patients. Similar to the current study, Ong et al. showed inefficiency of QDR criteria in patients under 40 (5). Orloski et al. inves- tigated 7,209 patients with dislocation, 465 (6.5%) of which had associated fracture. They found that a small percentage of fractures occurred in the second (0.7%) and third (0.8%) decades of life. The prevalence of fracture in the fourth and fifth decades of life was 2.6% and 4.6%, respectively. This rate increased by at least 19% in the 8th-10th decades of life. Not performing pre-reduction radiography for patients in their second and third decades of life may reduce pre-reduction radiography by 40%. According to them, since the risk of frac- ture is below 1% in the second and third decades of life, the use of routine pre-reduction radiography for patients with shoulder dislocation can be reduced, which is inconsistent with our findings (14). In our study, both LR+ and LR- in to- tal population were similar with regard to the ability to dif- ferentiate patients who need radiography from those who do not. In other words, there is no difference in using this tool as a "screening" or "definite diagnosis" method for perform- ing radiography before reduction. However, the highest LR+ was observed in females, it seems that it can be used as an acceptable "screening" tool in this gender. 5. Limitation In this study, sample size and hospital selection were among the limitations and studies with larger sample size and differ- ent hospitals are needed to confirm our results. 6. Conclusion QDR holds promise to accurately diagnose fracture- associated shoulder dislocation in patients above 40 years with a sensitivity of 100%. It can also reduce unnecessary radiographies in such patients by 50% without leaving any fracture undetected. 7. Appendix 7.1. Acknowledgements The research team would like to thank the nursing staff and the emergency medical staff of Imam Reza (P.b.h) & Shahid Hasheminejad Hospitals of Mashhad, who collaborated in the study. 7.2. Author contribution Study design, literature search, data gathering and analysis were done by EB, BA, MF, BA, RH and RA. Manuscript prepa- ration and drafting were done by all authors. Final version of the manuscript was accepted by all authors. Authors ORCIDs Ehsan Bolvardi: 0000-0001-6819-9237 Mahdi Foroughian: 0000-0002-3944-9361 Bita Abbasi: 0000-0001-9162-2312 Seyed Reza Habibzadeh: 0000-0003-4569-1776 Reza Akhavan: 0000-0002-2501-3815 7.3. Funding/Support The study was financially supported by Mashhad University of Medical Sciences, and accepted by Deputy of Research of Mashhad University of medical sciences as an approved pro- posal receiving the code 940521. 7.4. Conflict of interest The authors declare that there are no conflicts of interest re- garding the publication of this manuscript. References 1. Cunningham NJ. Techniques for reduction of anteroinfe- rior shoulder dislocation. Emergency Medicine Australa- sia. 2005;17(5-6):463-71. 2. Kesmezacar H. The evaluation and treatment of acute anterior shoulder dislocation. Acta orthopaedica et trau- matologica turcica. 2005;39:40-7. 3. Uehara D, Rudzinski J. [Injuries to the shoulder complex and humerus. Emergency Medicine: a comprehensive study guide] 5th ed ed. New York: McGraw-Hill; 2000. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). 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The American journal of emergency medicine. 1999;17(7):653-8. 14. Orloski J, Eskin B, Allegra PC, Allegra JR. Do all pa- tients with shoulder dislocations need prereduction x- rays? The American journal of emergency medicine. 2011;29(6):609-12. 15. Ortells Abuye N. Shoulder dislocations attended in a re- gional hospital: are all the radiographs ordered neces- sary. Emergencias. 2014;26:121-4. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem Introduction Methods Results Discussion Limitation Conclusion Appendix References