Shoulder dislocations

Question 1

What is the most common type of shoulder dislocation?

Answer 1

Anterior - 95%

Humeral head dislocation antero-inferiorly

Question 2

What can cause an anterior shoulder dislocation?

Answer 2

Direct trauma

Falling on hand

Question 3

What are some predisposing factors for shoulder dislocation?

Answer 3

A flattened/shallow anterior/antero-inferior glenoid bony contour (may predispose to recurrent dislocations)

Question 4

How can anterior shoulder dislocations be classified?

Answer 4

Dependent on where the humeral head lies;
Subcoracoid (most common)
Subglenoid
Subclavicular
Intrathoracic (very rare)

Question 5

What is the treatment of anterior shoulder dislocations?

Answer 5

Closed reduction
Immobilisation for 6 weeks
Allows adequate capsular healing
Physiotherapy to help maintain muscle mass and mobility

Question 6

When would surgical repair be required for an anterior shoulder dislocation?

Answer 6

Treats complications/associated injuries;
Inferior glenohumeral ligament damage
intra-articular lose body
Damage to axillary artery/brachial plexus
Bankart lesion
Hill-Sachs lesion

Question 7

What can cause a posterior shoulder dislocation?

Answer 7

Direct trauma (Tend to be when arm is internally rotated and abducted)
Strong muscle contraction eg electrocution, epileptic seizures (Bilateral dislocations more common)

Question 8

What is needed to diagnose a posterior shoulder dislocation?

Answer 8

An axillary view x-ray

Anterior view may look normal

Question 9

What is the lightbulb sign?

Answer 9

An internally rotated humeral head takes on a rounded appearance in the axillary view xray
Seen in posterior shoulder dislocation

Question 10

What is the rim sign?

Answer 10

A widened glenohumeral joint > 6 mm

Seen in posterior shoulder dislocation

Question 11

What are some of the injuries associated with a posterior shoulder dislocation?

Answer 11

Reverse Bankart lesion
Reverse Hill-Sachs lesion
Fracture of the lesser tuberosity
Posterior HAGL lesion (Humeral Avulsion of the Glenohumeral Ligament - Avulsion of inferior glenohumeral ligament from its humeral insertion)

Question 12

What is the treatment of a posterior shoulder dislocation?

Answer 12

Closed reduction, but if been dislocated for more than 3 weeks or a reverse Hill-Sachs lesion covering more than 20% of the articular surface is present then it is contraindicated
Neurovascular compromise uncommon

Question 13

What is shoulder pseudodislocation?

Answer 13

On AP projection an inferiorly subluxed humeral head can mimic a posterior shoulder dislocation

Question 14

What is the specific management of a shoulder dislocation?

Answer 14

A-E assessment
Assess for neurovascular deficit - especially axillary nerve over deltoid (Regimental badge area)
X-ray (AP, Axillary)
Closed reduction under sedation
Rest arm in sling for 4-6 weeks
Physiotherapy

Question 15

What are the two methods for reducing a dislocated shoulder?

Answer 15

Hippocratic - Longitudinal traction, arm in 30
abduction and counter traction at axilla
Kocher’s - external rotation of adducted arm,
anterior movement, internal rotation

Question 16

What are the main complications of a shoulder dislocation?

Answer 16

Neurovascular damage
Recurrent dislocations
Bankart lesions
Hill-Sachs lesions

Question 17

What is a Bankart lesion?

Answer 17

Damage to anterioinferior glenoid labrum after anterior shoulder dislocation
Called reverse Bankart lesion if after posterior dislocation

Question 18

What is a Hill-Sachs lesion?

Answer 18

Cortical depression in the posterolateral part of the humeral head following impaction against the glenoid rim during anterior dislocation.
Called reverse Hill-Sachs lesion if after posterior dislocation

Question 19

How would a shoulder dislocation present?

Answer 19

The contour of the shoulder may be lost - square looking
There may be a bulge in the infraclavicular fossa which is the humeral head
Severe pain
Weight of the arm supported by other arm