What is the diagnosis?

Inferior shoulder dislocation aka luxatio erecta.

• Pearl: Shoulder dislocation is one of the most common dislocations seen in the Emergency Department, and represents 50% of all major joint dislocations [1,2]. Inferior dislocations are rare and represent only 0.5% of all shoulder dislocations [3].

What are the mechanisms of injury?

Axial loading through a fully abducted arm which drives the humeral head through the weaker inferior glenohumeral ligaments [4]. 

Or

Hyperabduction force to the arm which levers the proximal humerus on the acromion and results in injury to the inferior and middle glenohumeral ligaments [4].

What physical exam findings are expected?

The diagnosis can be made through a physical exam alone: the arm is typically in a fixed, abducted position above the patient’s head with the humeral head palpable in the axilla [4]. 

• Pearl: Maintain a high index of suspicion for neurovascular injury because the brachial plexus and axillary artery run inferiorly to the glenohumeral joint [5]. 

Figure 2. Patient with inferior shoulder dislocation and arm in a fixed abduction positive. Courtesy of Mark Hopkins, MD.  

Which imaging modalities can be used?

Plain radiographs are used to confirm the diagnosis and look for associated fractures. The humeral head is displaced inferiorly from the glenoid fossa and the humeral head is typically parallel to the spine of the scapula [4]. 

What is the management in the ED?

Traction-countertraction: axial traction is applied in the direction of the abducted humerus and countertraction is provided by a rolled sheet across the top of the shoulder [4,6]. This typically requires procedural sedation [6]. 

2-step maneuver [7]: The patient lies supine and the provider stands on the affected side next to the head of the patient. Place one hand on the lateral aspect of the mid shaft of the humerus and push inferiorly [6,7]. Meanwhile, place the other hand over the medial epicondyle and provide force superiorly [6,7]. This converts the inferior dislocation to an anterior dislocation, and a variety of reduction maneuvers can then be performed [4,6,7].

What is the definitive management of this injury? Do I need to consult Orthopaedics?

In most cases, non-operative treatment with sling immobilization for 2-3 weeks followed by physical therapy is appropriate [4]. Orthopedics should be consulted in the Emergency Department if there is neurovascular injury, open dislocation, fracture-dislocation, or irreducible dislocations when the humeral head “buttonholes” through the inferior capsule. Operative management may also be needed for capsular reconstruction and rotator cuff injury [3,4,7].