Difference between revisions of "Posterior shoulder dislocation"

(Mechanism)
(Management)
 
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**Lack of normal overlap of humeral head and glenoid fossa
 
**Lack of normal overlap of humeral head and glenoid fossa
 
**"Light bulb sign" - fixed internal rotation makes for light bulb appearance of humeral head on AP
 
**"Light bulb sign" - fixed internal rotation makes for light bulb appearance of humeral head on AP
 +
*Consider CT for occult dislocations of evaluation of fractures
 
*Bedside [[ultrasound: Joint|ultrasound]] can be used to assess for both dislocation and successful reduction
 
*Bedside [[ultrasound: Joint|ultrasound]] can be used to assess for both dislocation and successful reduction
  
 
==Management==
 
==Management==
*Closed reduction
+
===Closed reduction===
**Most require [[procedural sedation]]
+
''Most require [[procedural sedation]]''
 
#Adduct the arm
 
#Adduct the arm
 
#Apply traction along long axis of humerus
 
#Apply traction along long axis of humerus
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#Apply shoulder immobilizer
 
#Apply shoulder immobilizer
 
#Obtain post-reduction radiographs
 
#Obtain post-reduction radiographs
*'''Note: Do not reduce chronic dislocations (>4 weeks) in the ED due to risk of arterial injury''' - consult ortho for open reduction
+
 
 +
===Indications for Surgery===
 +
*Lesser tuberosity displacement not reduced with reduction
 +
*Articular defect >25%
 +
*Dislocation >3 weeks
 +
**Do not reduce chronic dislocations in the ED due to risk of arterial injury; consult ortho for open reduction
  
 
==Disposition==
 
==Disposition==
 
*Discharge after successful reduction
 
*Discharge after successful reduction
*Orthopedic surgery outpatient follow-up
+
**Maintain [[sling +/- swath]] or shoulder immobilizer (shoulder in adduction and internal rotation) until seen in follow-up by orthopedic surgery
 
*Any patient with a chronic dislocation requires orthopedic consult in the ED for consideration of operative reduction due to the risk of arterial injury
 
*Any patient with a chronic dislocation requires orthopedic consult in the ED for consideration of operative reduction due to the risk of arterial injury
 +
 +
==Complications==
 +
*[[Humerus fracture]] plus fracture of the posterior glenoid rim
 +
*Isolate fracture of lesser tuberosity
 +
*Reverse Hill-Sachs deformity
 +
**Impaction fracture of anteromedial humeral head
  
 
==See Also==
 
==See Also==

Latest revision as of 20:27, 22 June 2020

Background

Left shoulder and acromioclavicular joints with ligaments.
Shoulder anatomy, anterior.
Shoulder anatomy, posterior.
  • 2-4% of shoulder dislocations[1]
  • Complications (neurovascular injuries and rotator cuff tears) less common than in anterior dislocation
  • May go undetected for extended period as often missed on physical exam and imaging

Shoulder dislocation types

Clinical Features

  • Posterior aspect of shoulder unusually prominent
  • Anterior aspect of shoulder appears flattened
  • Inability to rotate or abduct affected arm

Mechanism

  • Forceful internal rotation and adduction
    • Usually due to seizure or electric shock
  • Blow to anterior shoulder

Differential Diagnosis

Shoulder and Upper Arm Diagnoses

Traumatic/Acute:

Nontraumatic/Chronic:

Refered pain & non-orthopedic causes:

Evaluation

Light bulb sign (left) with post-reduction comparison (right)
  • Plain film X-ray
    • Scapular "Y" view shows humeral head in posterior position
    • Lack of normal overlap of humeral head and glenoid fossa
    • "Light bulb sign" - fixed internal rotation makes for light bulb appearance of humeral head on AP
  • Consider CT for occult dislocations of evaluation of fractures
  • Bedside ultrasound can be used to assess for both dislocation and successful reduction

Management

Closed reduction

Most require procedural sedation

  1. Adduct the arm
  2. Apply traction along long axis of humerus
  3. Have assistant push humeral head anteriorly into glenoid fossa
  4. Apply shoulder immobilizer
  5. Obtain post-reduction radiographs

Indications for Surgery

  • Lesser tuberosity displacement not reduced with reduction
  • Articular defect >25%
  • Dislocation >3 weeks
    • Do not reduce chronic dislocations in the ED due to risk of arterial injury; consult ortho for open reduction

Disposition

  • Discharge after successful reduction
    • Maintain sling +/- swath or shoulder immobilizer (shoulder in adduction and internal rotation) until seen in follow-up by orthopedic surgery
  • Any patient with a chronic dislocation requires orthopedic consult in the ED for consideration of operative reduction due to the risk of arterial injury

Complications

  • Humerus fracture plus fracture of the posterior glenoid rim
  • Isolate fracture of lesser tuberosity
  • Reverse Hill-Sachs deformity
    • Impaction fracture of anteromedial humeral head

See Also

External Links

References

  1. Grate I Jr. Luxatio erecta: a rarely seen, but often missed shoulder dislocation. Am J Emerg Med. 2000 May;18(3):317-21.