Resident Clinical Pearl – POCUS in Shoulder Dislocation
Luke Richardson, PGY 3 Emergency Medicine, Dalhousie University, Saint John, New Brunswick
Reviewed by Dr. David Lewis
A 24 year old male rugby player presents to the emergency department with left sided shoulder pain. He reports being hit in the middle of the game followed by a pop to his shoulder. Since that time he has had ongoing pain and limited movement. His vitals are normal but he appears uncomfortable. He shows no signs of neurological or vascular injury. History and physical exam is otherwise benign.
Dislocated shoulder is suspected, but is there a way to quickly diagnose prior to x-ray and therefore expedite administration of pre-procedural analgesia and preparation of procedural team and room?
POCUS: Shoulder Background
The shoulder is a ball-in-socket joint with a large range of motion and has a high risk of dislocation due to its shallow joint depth and limited tendinous support inferiorly. Most commonly, the shoulder will dislocate with the humeral head anterior to the glenohumeral rim due to an superiorly placed force upon the humeral head. Posterior dislocations are less common and commonly due to higher mechanism of injuries such as seizure or electrical shock.
Diagnosis of shoulder dislocation is commonly made by x-ray but this method has its downsides including time to diagnosis and increased radiation exposure. An important consideration is the use of POCUS during shoulder reduction. This technique allows for real time confirmation and potentially avoids the need for repeat sedation if failed reduction discovered by a trip to the x-ray department. A recent prospective observational study of 73 patients in the emergency department revealed an accuracy of 100% sensitivity and specificity for shoulder dislocation and relocation (reference 1). Finally, considering there is increased risk of neuro-vascular complications with time to relocation; a decrease in duration to diagnosis could potentially improve patient care.
POCUS: Shoulder Technique
Get patient to sit up to allow availability to the posterior portion of the patient shoulder.
Support the patients elbow while positioning the shoulder in adduction and internal rotation.
Using the curvilinear probe, landmark just inferior to the scapular spine and follow it laterally until you find the glenoid (G) and humeral head (HH) (Shol1).
Shol 1
You should find the humeral head (HH) as a circular structure lateral to the glenoid fossa (G) if in joint. Note the Glenoid labrum (L).
To confirm, you can internally and externally rotate the arm and visualize the humeral head freely moving within the glenoid (Shol2/Shol4) (reference 2). Note the overlying deltoid (most superficial) and the infraspinatus tendon that becomes more apparent during internal rotation.
Shol2
Shol4
If the shoulder is anteriorly dislocated you will see the humeral head displaced inferiorly (Shol5/Shol6) (reference 2,3)
If the shoulder is posteriorly dislocated you will see the humeral head more superficial than expected (Shol5) (reference 2,3)
Shol5
Shol6
Conclusion:
POCUS is an easily available and non-invasive tool in the emergency department. It can be used in cases such as this to improve patient flow, decrease time to diagnosis, and confirm reduction.
Reference:
- Abbasi, S., Molaie, H., Hafezimoghadam, P., Amin Zare, M., Abbasi, M., Rezai, M., Farsi, D. Diagnostic accuracy of ultrasonogrpahic examination in the management of shoulder dislocation in the emergency department. Annals of Emergency Medicine. Volume 62:2. August, 2013, pg. 170-175.
- Tin, J., Simmons, C., Ditkowsky, J., Alerhand, S., Singh,M., US Probe: ultrasound for shoulder dislocation and reduction. EMDocs http://www.emdocs.net/us-probe-ultrasound-for-shoulder-dislocation-and-reduction/ January 18, 2018.
- Rich, C., Wu, S., Ye, T., Liebmann, O. Pocus: shoulder dislocation. Brown Emergency Medicine. http://brownemblog.com/blog-1/2016/11/30/pocus-shoulder-dislocation. November 30th, 2016.
