POCUS For Shoulder Dislocation

POCUS For Shoulder Dislocation

Introduction

Shoulder (glenohumeral) dislocation is a common clinical presentation in the emergency department, comprising about 50 percent of all major joint dislocations. The large range of motion of the shoulder with minimal inferior tendinous support makes it prone to dislocation. Plain film radiography has been the imaging modality of choice for most clinicians when evaluating the ED patient with a suspected shoulder dislocation. Recent literature has demonstrated the superiority of point-of-care ultrasound (POCUS) in detecting both anterior and posterior shoulder dislocations, making it another rapidly evolving tool to improve accuracy, decrease error, and improve efficiency.

Also, real-time ultrasonographic assessment of the articulation between the glenoid fossa and the humeral head is the ideal test when patients undergo procedural sedation for reduction. After shoulder manipulation, confirmation of the reduction attempt by plain film radiography incurs a delay that can prolong the length of stay. POCUS allows for a dynamic evaluation of the glenohumeral joint, immediately informing the clinician of a successful reduction or the need for additional shoulder manipulation without having to rely on plain film radiography.

Ultrasound Evaluation of the Shoulder Dislocation

Procedure 

It is recommended to use the low-frequency (5-2 MHz) curvilinear transducer for this examination. While standing behind the affected shoulder, place the ultrasound system in front of the patient so that a clear view of the screen can be obtained (see Figure 1). 

If possible, ask the patient to adduct the humerus while supporting the elbow inferiorly for comfort. Palpate the scapular spine and follow it laterally toward the humerus (see also Figure 1). Place the probe parallel and just below the scapular spine with the probe indicator to the patient’s left, at the level of the glenoid. Adjust the depth until both the glenoid and humeral head are clearly seen (see Figure 2). 

The humeral head appears as a circular object located just lateral to the glenoid fossa. With the more common anterior dislocation, the humeral head will be deep on the screen (see Figure 3), while with a posterior dislocation, the humeral head will be closer to the probe and, therefore, more superficial on the screen (see Figure 4). 

If the shoulder is not dislocated, the patient should be able to internally and externally rotate the shoulder while adducted, and the rotational articulation between the humeral head and glenoid fossa will be seen clearly on the ultrasound screen.

YouTube : In this brief tutorial we review the use of point of care ultrasound in detecting shoulder dislocations, confirming reductions and using ultrasound in ultrasound-guided intra-articular block.

Discussion :

Recently ultrasound of  shoulder has shown significant accuracy in detecting shoulder dislocation. One explanation was that in traumatic patients who experience severe pain, the clinical examinations may be inaccurate. The patients may not want to move their shoulders and complain from severe pain. Painful shoulder and resistance against motion could simulate shoulder dislocation.

Abbasi Et Al ( 2014 ) assessed diagnostic accuracy of ultrasonography in detecting shoulder dislocation and confirming proper reduction. Theses authors reported that ultrasonography did not miss any dislocation and the results of ultrasonography and radiography were identical and the sensitivity of ultrasonography was 100% in the detection of shoulder dislocation and 100% for the assessment of complete reduction of shoulder joint. Study population was one of the biggest among all other studies about this issue while other studies were just case reports and case series with small number of patients. It has shown ultrasonography and radiography were identical and the sensitivity of ultrasonography in detection of shoulder dislocation was 100% (95% confidence interval 93.4% to 100%). The sensitivity of ultrasonography for assessment of complete reduction of the shoulder joint reached 100% (95% confidence interval 93.2% to 100%) in the study involving 73 patients were enrolled. The ultrasonography did not miss any dislocation.

Blakeley Et Al demonstrated that bedside ultrasonography could correctly confirm successful reduction in 5 cases of anterior dislocation. Similarly, Halberg Et Al presented 2 cases of anterior and posterior shoulder dislocation for which the success of the reduction process was confirmed correctly with ultrasonography. Posterior shoulder dislocations may easily be missed either by clinical examination or radiography. Yuen Et Al reported 2 cases of acute posterior shoulder dislocation confirmed by bedside ultrasonographic scan. They concluded that bedside ultrasonography for diagnosis of posterior shoulder dislocation was accurate, noninvasive, repeatable, convenient, and without ionizing radiation..

Another recent study performed in the Department of Emergency Medicine, Tabriz University of Medical Sciences by Hamidreza Morteza Baighi Et Al ,  a comparison of radiography and ultrasonography operations performed on the shoulders to diagnose anterior shoulder dislocation and control reduction the sensitivity and specificity of the ultrasonography performed to diagnose shoulder dislocation were 94% and 95%, respectively. Moreover, the positive and negative predictive value of the ultrasonography results was 95.5% and 92.5%, respectively. The sensitivity and specificity of the ultrasonography performed to control shoulder dislocation reduction were 90% and 100%, respectively.

In a study by Mackenzie Et Al (2013), which was performed in the Emergency Department of Warren Alpert University in the Rhodel Island state (United States), the role ultrasonography in the diagnosis of shoulder dislocation was studied. The researchers stated that shoulder ultrasonography is a useful diagnostic method for patients with shoulder dislocation. They introduced it as useful
method for diagnosis of shoulder dislocation that can be used to control patients after reduction as well . In a study by Wittner Et Al the diagnostic precision of shoulder dislocation ultrasonography was studied. They reported that shoulder dislocation ultrasonography demonstrated a sensitivity of 97.7% and specificity of 92.3% in diagnosing shoulder dislocation.  In the present study, the sensitivity of ultrasonography in diagnosing anterior shoulder dislocation was shown to be 94%, which was high similar to the figure reported by the latter research.

In a study by Bianchi Et Al , which was performed in the University of Genoa in Italy, the role of shoulder ultrasonography in the diagnosis of shoulder dislocation was studied. The researchers stated that performing ultrasonography on such patients in the emergency department is a useful and effective way of diagnosing shoulder dislocation in patients visiting the emergency department.

In 2008, Kerkovsky Et Al conducted a study in the emergency department of Czech University to analyze the role of ultrasonography in the diagnosis of traumatic lesions. They introduced shoulder ultrasonography as a useful means of examining shoulder traumatic lesions.

In the research by Jerosch Et Al, which was performed in the Hemut Schemidt University of Dusseldrorf (Germany), the role of shoulder ultrasonography in the diagnosis of shoulder injuries was studied. The researchers reported a specificity of 100% and sensitivity of 89% for shoulder
dislocation diagnostic ultrasonography. In the present study, the specificity of the ultrasonography performed to examine anterior shoulder dislocation and lesions was 95%. This figure reflects a high specificity similar to the latter study.

Shudter Et Al carried out a study to analyze the role of ultrasonography procedures performed by emergency department physicians to diagnose anterior shoulder dislocation. They reported that the emergency physicians was able to use ultrasonography to diagnose 93.7% of the patients with should dislocation.

Conclusion

In summary, these results provide promising preliminary support for the ability of ultrasonography to detect shoulder dislocation, but further investigation is necessary both to confirm these results and to estimate with greater precision the ability of ultrasonography to detect fractures associated with dislocation. Ultrasonography may reduce the number of radiographs and time elapsed in the Emergency Department and allows physicians to spend sufficient time on more acute patients, especially in crowded Emergency Department in major cities. 

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