What is your diagnosis?

Anterior glenohumeral (GH) joint dislocation. Note that the humeral head is displaced inferiorly in the AP view and that the humerus is displaced to the right (or anterior) of the scapular “Y”. 

What is your next step in the ED?

Attempt a shoulder reduction with proper anesthesia/analgesia and consent. 

What is your next step?

Request a repeat scapular Y view.  Image 2 is a case where a repeat scapular Y view should be re-ordered as a definitive diagnosis is difficult to establish. See Image 3 for the repeat scapular Y.

Image 3. Author’s own images. Repeat scapular Y view of the right shoulder after the initial reduction attempt. Annotated humeral head, note that the humerus (orange dotted) does not project directly over the “Y” of the scapula (green dotted). A - acromion. C - coracoid.

What are the appropriate shoulder x-rays to obtain in the ED?

Plain films of the shoulder in the ED should consist of at least an AP view and a lateral view or scapular Y view. In a proper Y view the acromion and coracoid will form the upper portion of the “Y” and the humerus should project directly over the glenoid if not dislocated. The scapular body should have a thin profile on the Y view indicating it is not over or under-rotated [1]. See Image 3.

• Pearl: An axillary view can also be useful to evaluate the glenohumeral joint and can be used to rule in/out dislocation. This view can be difficult to obtain in an acute dislocation due to the pain associated with positioning.

Image 4. Normal axillary view. Case courtesy of Dai Roberts, Radiopaedia.org, rID: 80414

What other modalities are useful in the workup of this condition?

Ultrasound (US). It can be used to both detect a shoulder dislocation and to confirm successful reduction. Based on a recent meta-analysis, GH US has a sensitivity and specificity of 100% for diagnosis of GH joint dislocation [2]. In the author’s case, ultrasound was used before reduction (Image 5) and after the initial reduction attempt. The glenohumeral joint appeared to be in anatomic alignment as detailed in Image 6 below. Dynamic assessment of the joint can also be done using ultrasound.

Image 5. Author’s own images. Pre-reduction ultrasound (top) showing anterior GH joint dislocation. Post-reduction ultrasound (bottom) showing alignment of the humeral head with the glenoid. Note the humeral head depth decreased from 5 cm to 3 cm on the US after reduction.

What is your final disposition and follow up plan?

This patient had significant laxity appreciated on his repeat reduction. He will require outpatient orthopedic surgery follow up. In general patients should be placed in a sling post reduction and should follow up with either primary care sports medicine or orthopedic surgery. The frequency of rotator cuff tears can vary between 7% and 32% after an anterior dislocation. . Patients who lack follow up and have rotator cuff or other associated injuries can run the risk of developing adhesive capsulitis, pain, instability and/or degenerative changes [3].

• Pearl: Risk for rotator cuff injury increases with increasing age [3]