Difference between revisions of "Posterior shoulder dislocation"

(Created page with "==Background== *Via forceful internal rotation/adduction (sz, electric shock) or blow to ant shoulder *Neurovascular and rotator cuff tears are less common than in ant disloca...")
 
(Management)
 
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==Background==
 
==Background==
*Via forceful internal rotation/adduction (sz, electric shock) or blow to ant shoulder
+
[[File:Gray326.png|thumb|Left shoulder and acromioclavicular joints with ligaments.]]
*Neurovascular and rotator cuff tears are less common than in ant dislocations
+
[[File:Shoulder_joint_back-en.png|thumb|Shoulder anatomy, anterior.]]
 +
[[File:Shoulder joint back 05r4v.png|thumb|Shoulder anatomy, posterior.]]
 +
*2-4% of shoulder dislocations<ref>Grate I Jr. Luxatio erecta: a rarely seen, but often missed shoulder dislocation. Am J Emerg Med. 2000 May;18(3):317-21.</ref>
 +
*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==
 
==Clinical Features==
*Prominence of posterior shoulder and ant flattening of normal shoulder contour
+
*Posterior aspect of shoulder unusually prominent
*Pt unable to rotate or abduct affected arm
+
*Anterior aspect of shoulder appears flattened
 +
*Inability to rotate or abduct affected arm
  
==Diagnosis==
+
===Mechanism===
===Imaging===
+
*Forceful internal rotation and adduction
*Scapular "Y" view shows humeral head in posterior position
+
**Usually due to seizure or electric shock
 +
***Consider in [[alcohol withdrawal]], even without clear history of shoulder injury
 +
*Blow to anterior shoulder
  
 
==Differential Diagnosis==
 
==Differential Diagnosis==
 +
{{Shoulder DDX}}
 +
 +
==Evaluation==
 +
[[File:Lightbulb sign - posterior shoulder dislocation - Roe vor und nach Reposition 001.jpg|thumb|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: Joint|ultrasound]] can be used to assess for both dislocation and successful reduction
 +
 +
==Management==
 +
===Closed reduction===
 +
''Most require [[procedural sedation]]''
 +
#Adduct the arm
 +
#Apply traction along long axis of humerus
 +
#Have assistant push humeral head anteriorly into glenoid fossa
 +
#Apply shoulder immobilizer
 +
#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==
 
*[[Shoulder dislocation]]
 
*[[Shoulder dislocation]]
**[[Anterior shoulder dislocation]]
 
**[[Posterior shoulder dislocation]]
 
**[[Inferior shoulder dislocation]]
 
  
==Management==
+
==External Links==
*Reduce
+
*https://youtu.be/KRCqVekNEKc
**Traction applied to adducted arm in long axis of humerus
 
**Assistant pushes humeral head anteriorly into glenoid fossa
 
*Spling, ortho f/u
 
  
 
==References==
 
==References==
 
<references/>
 
<references/>
  
[[Category:Ortho]]
+
[[Category:Orthopedics]]
 +
[[Category:Procedures]]

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.