What is your diagnosis?

Anterior shoulder dislocation. You can see the humeral head inferior to the glenoid on the AP view and anterior to the scapula/glenoid on the lateral/scapular-Y view

Image 3-4: Author’s own images and annotations. 

What other x-ray views can you use if you are unsure?

When ordering a shoulder x-ray, typically two views are obtained, an AP and lateral view. Which lateral view is taken can vary, but the most useful for diagnosing shoulder dislocations is the scapular-Y (Image 4-5). Additionally, a 3rd view called an axillary view (Image 6) can be crucial to diagnosing subtle dislocations that may not be obvious on an AP or scapular-Y. [1]

• Pitfall: Be careful with the scapular-Y view when evaluating for a shoulder dislocation. If the view is not a true/perfect lateral, the humeral head can look falsely located or dislocated. A true lateral scapular-Y view will show the scapula as a line. Notice Image 2 which shows some of the body of the scapula, making it an inadequate lateral view (though there is still a clear dislocation). 

• Pearl: In addition to standard x-ray, bedside ultrasound is a valuable tool to assess for glenohumeral alignment. Using a posterior approach, the joint can be evaluated in real time and compared to the other side to assess for initial status and post-reduction status. 

Image 7-8: Ultrasound views off the glenohumeral joint from the posterior approach showing normal alignment and an anterior/posterior dislocation. Courtesy of http://www.emdocs.net/em3am-anterior-shoulder-dislocation/

What are potential complications of this injury?

Anterior shoulder dislocations are associated with a variety of other bony and soft tissue injuries as well as potential neurovascular complications. The most common injury is a Hill-Sachs lesion (humeral head indentation) and most common nerve injury is an axillary nerve neuropraxia. While more rare, Bankart lesions (glenoid chip fracture), greater tuberosity fractures, brachial plexus injuries, rotator cuff injuries, and axillary artery injuries can also occur [2].

• Pearl: The axillary nerve innervates the skin over the deltoid, making quick evaluation easy by doing a sensory exam

What is your management in the ED? Does orthopedics need to be consulted?

Management in the ED includes expedited reduction with neurovascular status checked before and after. There are numerous techniques for analgesia/sedation and reduction techniques. For analgesia, the patient’s presentation will dictate the necessary medications. For many patients, no or minimal analgesia can be used depending on the reduction technique. For others, an intra-articular injection of lidocaine may be sufficient. For patients in extreme pain or who are unable to participate in reduction techniques, a full procedural sedation may be required. 

For reduction techniques, everyone has their favorite method. Generally speaking, 1-2 attempts with one method is enough to determine if that method will not work. Most methods have about the same success rates based on the literature and if one doesn't work, trying another one is usually successful.  Traditional teaching is to get a post-reduction x-ray to confirm placement, though many recent articles have not shown benefit to this when the provider is sure of clinical reduction [3]. 

Orthopedics typically does not need to be consulted in the ED if reduction is successful and there is no neurovascular compromise. If reduction is unsuccessful despite numerous attempts and/or with sedation, a CT scan may be warranted for cross-sectional imaging of the joint to evaluate for mechanical blocks. Additionally, orthopedics may be consulted for an operative reduction under anesthesia if reduction is unable to be completed in the ED. Follow up with orthopedics DOES need to be established as patients will be followed and potentially offered operative repair depending on the situation.

• Pearl: For an in-depth review of many of the techniques, this article has extensive information with photos: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5154590/ [4]