Shoulder Dislocation

Last Updated on by FRCEM Intermediate

Anterior shoulder dislocation

Mechanism

  • caused by a blow to the abducted, externally rotated, and extended arm.

Clinical features

  • Arm is slightly abducted and externally rotated
  • Affected arm supported by unaffected arm
  • Flat shoulder deformity (loss of normal rounded appearance of shoulder)
  • Step-off deformity at the acromion with palpable gap below the acromion
  • Humeral head palpable anteroinferiorly to the glenoid
  • Patient resists all movements

X-ray

  • Loss of congruity between the humeral head and glenoid
  • The humeral head is displaced medially and inferiorly on an AP shoulder x-ray

Reduction methods

Reduce under sedation/analgesia:

  • External rotation method
  • Kocher’s method
  • Modified Milch method

If unsuccessful, difficult, or shoulder has been dislocated > 24 hours or dislocation is associated with fracture – refer for reduction under GA

Complications

  • Hill-Sachs lesion (humeral head compression fracture)
  • Bankart lesion (disruption of glenoid labrum +/- bony avulsion)
  • Greater tuberosity fracture
  • Axillary artery damage
  • Axillary nerve damage
  • Brachial plexus damage
  • Rotator cuff injury
  • Shoulder instability and recurrence of dislocation

 

Posterior Shoulder Dislocation:

Mechanism

  • A blow to the anterior portion of the shoulder,
  • axial loading of an adducted and internally rotated arm
  • violent muscle contractions following a seizure or electrocution

Clinical Feature

  • Patient presents with shoulder internally rotated and adducted
  • There is a limited range of active and passive external rotation, and the humeral head may be palpated in a posterior position

X-ray

  • Widening of the glenohumeral gap, and lightbulb sign (abnormally symmetrical appearance of humeral head)
  • Modified axial shoulder x-ray or transthoracic lateral view will confirm posterior dislocation

Management

  • Closed reduction

Complications

  • Tuberosity and surgical neck fractures of the humerus,
  • reverse Hill-Sachs lesions
  • injuries to the labrum
  • rotator cuff

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