By Michael Joseph MD, Natalie Moore MD, Jessica Patterson MD, Kelly Goodsell MD, & Meghan Kelly Herbst MD
Chief Complaint: Right shoulder pain
A thin 28-year-old male with history of recurrent right anterior shoulder dislocations presented to the emergency department (ED) unable to move his right shoulder. While playing basketball, he reached up over his head for a rebound, felt a pop and was subsequently unable to lift his arm without significant pain. There was no direct trauma to the shoulder. On exam, the patient was comfortable resting his right arm in slight flexion, abduction and external rotation. The right acromion was prominent with loss of rounded contour of the shoulder compared to the left. There was no bony tenderness, crepitus or appreciable deformity of the joint. The distal neurovascular exam was intact, including sensation over the deltoid. Pain was elicited with both active and passive flexion and rotation.
POCUS was performed using a low-frequency curvilinear probe placed along the posterior aspect of the right shoulder, inferior to the scapular spine (see image below), which confirmed the anterior relation of the humeral head with respect to the glenoid (See clip 1).
The overlying skin was prepped with chlorhexidine and a wheal of 1% lidocaine was raised. An intra-articular lidocaine (IAL) injection was performed under ultrasound guidance using a 1.5” 22G needle (See clip 2). The patient experienced significant pain relief within 15 minutes and was successfully reduced (See clip 3). He was immobilized in a sling and discharged with orthopedic follow-up.
Role of POCUS in the Emergency Department:
POCUS has been shown to have both diagnostic and therapeutic utility for patients suspected of acute anterior shoulder dislocation in the ED. Several studies have demonstrated point-of-care ultrasound in the hands of emergency physicians is highly sensitive for the diagnosis of both anterior and posterior dislocation.1-4 Ultrasound also has a role in improving and ensuring successful IAL injections for analgesia and facilitation of closed reduction.5,6 Although no studies have yet assessed patient-oriented outcomes with intra-glenohumeral lidocaine injection, a cadaver study demonstrated significant improvement in accuracy with ultrasound-guided injections.7 A Cochrane Review from 2011 showed that IAL injections resulted in equivalent reduction success compared to intravenous sedation and also decreased ED length of stay by approximately 109 minutes. Potential downsides to IAL-facilitated reduction include a low risk of septic arthritis, lack of anxiolysis for apprehensive patients, and higher risk of failure for large muscular patients unable to adequately relax their shoulder muscles.8 There is also emerging data that an ultrasound-guided block of the suprascapular nerve, which arises from the upper trunk of the brachial plexus (C5-C6) and provides the majority of sensory innervation to the glenohumeral joint, may be useful in the treatment of patients in the ED with anterior shoulder dislocation and can facilitate successful reduction.9 An ultrasound-guided suprascapular nerve block may be considered as a useful adjunct to ultrasound-guided IAL in lieu of procedural sedation.
1. The first clip was obtained with the curvilinear probe placed along the posterior glenohumeral joint just inferior and parallel to the scapular spine with the probe marker oriented medially. It shows the humeral head displaced in the far field (anteriorly) with respect to the glenoid with overlying effusion/hemarthrosis consistent with anterior shoulder dislocation.
2. There have been several small prospective, observational studies of emergency department patients that have found 100% sensitivity of ultrasound for the diagnosis of acute shoulder reduction when compared to radiographs (1-4). The studies vary in their probe selection, scan protocol and operator experience but they all suggest feasibility in the emergency setting. The pilot study by Lahham et al consisted of non-medical sonographers trained with a 30-minute anatomy tutorial and a 30-minute hands-on session. Participants were able to diagnosis anterior dislocation with 100% accuracy with a single posterior view of the glenohumeral joint.3 Abbasi et al. and Akyol et al demonstrated that related fractures including Hill-Sachs deformities and Bankart lesions could be identified in a small number of patients using a more complicated scanning protocol.2,4
3. There are currently no high-quality studies that evaluate an ultrasound only approach to management of suspected acute anterior shoulder dislocation. However, there are several studies that have attempted to define a low-risk cohort of patients that may forgo pre- and/or post-reduction plain films and provide some insight into the question (10-12). Emond et al examined 334 patients with anterior shoulder dislocation and found the absence of high-risk features had 97.7% sensitivity for ruling out a clinically significant fracture/dislocation requiring special care with reduction or surgical fixation. These features included 1) age > 40; 2) first occurrence of dislocation; 3) significant mechanism including fall from >1 flight of stairs, assault or MVC (10).
POCUS is a valuable diagnostic and therapeutic tool in the management of a significant number of patients presenting to the ED with acute anterior glenohumeral dislocation.