Shoulder Dislocation – Diagnosis, Complications and Reduction Techniques

Shoulder dislocation is classified based on the direction of displacement of the humeral head relative to the glenoid fossa.

• Anterior: These are the most common and account for over 95% of shoulder dislocations⁽¹⁾ They often occur due to forced abduction, external rotation, and extension, or fall on an outstretched hand. Present often with arm internally rotated and abducted. Shoulder may also be flattened in appearance with a prominent acromion.
• Posterior: Account for about 2-4% of shoulder dislocations⁽¹⁾

Often occur due to posterior force on humeral head while arm is internally rotated and abducted. Seizures, electrical shock, and trauma are potential causes. Presents with arm internally rotated, adducted, with prominence of the posterior shoulder

• Inferior: Accounts for less than 1% of shoulder dislocations

Also called luxation erecta, because the arm is held in a fixed upward position. Usually requires a high-energy force, resulting in forceful hyperabduction, or a large direct force on a hyperabducted arm. Concomitant injuries including humeral fracture, rotator cuff tears, and neurological injury may be frequent.⁽²⁾ Presents with arm in a fixed abducted position, often held over the head.

Radiological evaluation is obtained pre- and post reduction and can detect concomitant fractures or other deformities. However, there is differing opinion on the need for always getting pre-reduction x-rays. Remember the board answer may be different from actual clinical practice.

Pre-reduction x-rays may detect concurrent fractures or deformities such as the Hill-Sachs deformity or Bankart lesion, which may be a possible explanation for recurrent dislocations.

The Hill-Sachs deformity is a groove in the posterolateral portion of the humeral head. This is due to impaction of the humeral head against the glenoid rim.

The Bankart lesion causes disruption of the cartilaginous portion of the glenoid, resulting in detachment of a portion of the labrum from the glenoid, and can also involve the glenoid margin.⁽³⁾

Anterior dislocations show a humeral head displaced medially and overlying the glenoid fossa.⁽⁴⁾ Posterior films are usually harder to identify, as they may initially appear to be congruent on AP views. Lateral or “Y” views may be helpful to clarify a diagnosis.

Assessing neurovascular status is important before and after reduction. The most common nerve injury from an anterior dislocation involves the axillary nerve. Sensory function of the nerve can be tested over the lateral aspect of the deltoid region. Motor function is harder to test in a dislocated shoulder, but you would typically test deltoid strength. The brachial plexus is less commonly injured but rarely can be affected by stretch injury. Nerve injury doesn’t mean you don’t reduce the dislocation but can mean that you should be careful to avoid multiple traumatic attempts.

Vascular injury is rare, but axillary artery injury is possible and more common with anterior dislocations and in the elderly population. Palpate your radial pulse bilaterally, and feel for coolness of the extremity. This requires urgent evaluation and likely operative intervention.

Assess for associated fractures, particularly fractures of the humeral neck, which have a risk of displacement with closed reduction and can cause avascular necrosis.⁽⁴⁾

After assessing for neurovascular injury and concomitant fractures it is time to reduce this anterior dislocation. There are a number of accepted ways to reduce an anterior dislocation, and you should have few in your toolbox.

First off, make sure your patient has appropriate pain control. Intra-articular lidocaine, systemic analgesia, or even procedural sedation can be considered. The more your patient relaxes their muscles, the easier your reduction will be.

Here are a few techniques to try! Watch the attached links for how to instructions.

• Cunningham Technique
  • Arm adducted and elbows flexed
  • Massage biceps as the patient gradually moves shoulders up and back
• Milch Technique
  • Gradually abduct arm to overhead position
  • When at full abduction, apply longitudinal traction with slight external rotation
• External Rotation Technique
  • Fully adduct the arm with elbow flexed to 90 degrees
  • Hold the wrist, and slowly guide the arm into external rotation
• Scapular Manipulation Technique
  • Rotate the inferior tip of the scapula medially and dorsally toward the spine
  • Use with patient sitting up, and an assistant applying traction/counter-traction, or with other techniques.

Remember reduction is the primary management. But think twice about moving straight to ED reduction without consultation when you have significant neurovascular injury, humeral neck fractures, or a dislocation that has been present for greater than 48 hours (lower success rate).

Order post-reduction films to make sure your shoulder is back in place. However, ultrasound is another option for evaluating the glenohumeral joint and the success of reduction. Remember that it comes with some limitations, as it is user-dependent, and may not detect fractures or concomitant rotator cuff or labral tears.

Check out the Brown EM blog, for a great synopsis on POCUS for shoulder dislocation: Brown EM – POCUS for shoulder dislocation

If you decide to ultrasound, remember that for the humeral head will appear more superficial on the screen for a posterior dislocation, and deeper on an anterior dislocation.

Most patients without significant complications can be discharged home safely. Place the affected arm in a sling: 3-4 weeks for younger patients, 1-2 weeks for older patients as shorter immobilization prevents joint stiffening and maintains mobility. Early orthopedics follow-up is encouraged in older patients (5-7 days); 1-2 weeks for younger patients.

Now your shoulder’s reduced and your patient’s pain is a whole lot better. No jabbawockeez moves for the next few weeks, and you’re feeling a bit embarrassed. But don’t let that get you down, keep popping and locking friend. No judgment in the ED.