[7] Shoulder Dislocation

Question 1

Why are dislocations of the shoulder common?

Answer 1

Because the shoulder is a highly mobile joint, which sacrifices stability for an increased range of movement

Question 2

What can shoulder dislocations lead to if not managed correctly?

Answer 2

Chronic joint instability and pain

Question 3

What is the most common type of shoulder dislocation?

Answer 3

Anteroinferior (usually just termed ‘anterior’)

Question 4

What % of shoulder dislocations are anteroinferior?

Answer 4

Around 95%

Question 5

What are the less common types of shoulder dislocations?

Answer 5

• Posterior
• Inferior

Question 6

What classically causes an anterior shoulder dislocation?

Answer 6

Force being applied to an extended, abducted, and externally rotated humerus

Question 7

What classically causes posterior dislocations?

Answer 7

Seizures or electrocution

Question 8

How can posterior dislocations occur through trauma?

Answer 8

Direct blow to the anterior shoulder or force through a flexed, adducted arm

Question 9

Why are posterior dislocations important diagnostically?

Answer 9

They are the most commonly missed dislocation of the shoulder, especially as the radiographic evidence of them can be subtle

Question 10

How do shoulder dislocations present?

Answer 10

• Painful shoulder
• Acutely reduced mobility
• Feeling of instability
• Reluctance to move affected limb

Question 11

What may be found on examination in a dislocated shoulder?

Answer 11

• Asymmetry with the contralateral side
• Loss of shoulder contours
• Anterior buldge from head of humerus

Question 12

What is it important to assess in a should dislocation?

Answer 12

Neurovascular status of the arm

Question 13

Which nerves are most likely to be compromised in a shoulder dislocation?

Answer 13

Axillary and suprascapular nerves

Question 14

What bony injuries are commonly associated with shoulder dislocations?

Answer 14

• Bony Bankart lesions
• Hills-Sachs defects
• Fractures of greater tuberosity and surgical neck of humerus

Question 15

What are bony Bankart lesions?

Answer 15

Fractures of the anterior inferior glenoid bone

Question 16

Who are Bankart lesions most commony present in?

Answer 16

Those with recurrent dislocations

Question 17

What are Hills-Sachs lesions?

Answer 17

Impaction injuries to the chondral surface of the posterior and superior portions of the humeral head

Question 18

What % of traumatic dislocations are Hills-Sachs defects present in?

Answer 18

Approx 80%

Question 19

What labral and ligamentous injuries can be associated with shoulder dislocations?

Answer 19

• Soft Bankart lesions
• Glenohumeral ligament avulsion
• Rotator cuff injuries

Question 20

What are soft Bankart lesions?

Answer 20

Avulsions of the anterior labrum and inferior glenohumeral ligament

Question 21

What % of younger shoulder dislocation patients have at least 1 rotator cuff tear?

Answer 21

Around 1/3

Question 22

What forms the bulk of investigation for shoulder dislocations?

Answer 22

Imaging

Question 23

What imaging is required in shoulder dislocation?

Answer 23

A trauma series of plain radiographs

Question 24

What does a shoulder trauma series of plain radiographs consist of?

Answer 24

Anterior-posterior, Y-scapular, and axial views

Question 25

How does a trauma series confirm an anterior dislocation of the shoulder?

Answer 25

They can usually be seen on the AP film, as it is visibly out of the joint. The Y-scapular view will also confirm that it is anteriorly dislocated

Question 26

What x-ray finding suggests a posterior shoulder dislocation?

Answer 26

The 'light bulb sign'

Question 27

What produces the 'light-bulb' sign in posterior dislocations?

Answer 27

The humerus is fixed in internal rotation

Question 28

Which x-ray view is useful for differentiating between anterior and posterior dislocations?

Answer 28

Y view

Question 29

What investigation should be performed if labral and rotator cuff injuries are suspected?

Answer 29

MRI of the shoulder

Question 30

What should the immediate management of shoulder dislocations involve?

Answer 30

* A to E assessment * Stabilisation of injury * Examination for other injuries * Good, appropriate analgesia

Question 31

Why is A to E assessment important in shoulder dislocation?

Answer 31

As dislocations frequently occur following trauma

Question 32

How should shoulder dislocations be reduced?

Answer 32

Closed reduction, such as Hippocratic method *This should be performed by a trained specialist, involving orthopaedics early before attempting reduction*

Question 33

When should neurovascular status be assessed in shoulder dislocation?

Answer 33

Pre- and post-reduction

Question 34

What might a failed closed shoulder dislocation reduction warrent?

Answer 34

Attempted manipulation under anaesthesia in theatres

Question 35

How should a shoulder dislocation be managed once reduced?

Answer 35

Place arm in broad-arm sling

Question 36

How long should the arm be immobilised after shoulder dislocation?

Answer 36

Typically 2 weeks for anterior dislocation, longer for posterior dislocations

Question 37

Do all shoulder dislocations require physiotherapy?

Answer 37

Yes

Question 38

What is the aim of physiotherapy following shoulder dislocations?

Answer 38

Restore range of movement, functionality, and to strengthen the rotator cuff and pericapsular musculature

Question 39

When might further surgical treatment be required in shoulder dislocations?

Answer 39

If there is recurrent pain, instability, large Hills-Sachs defects, or large (bony) Bankart lesions

Question 40

What complications might arise from a shoulder dislocation despite treatment?

Answer 40

* Chronic pain * Limited mobility * Stiffness * Recurrence

Question 41

Is recurrence common following a shoulder dislocation?

Answer 41

Relatively, particularly in those who continue high risk activities

Question 42

What are the common complications for shoulder dislocations?

Answer 42

* Adhesive capsulitis * Nerve damage * Rotator cuff injury * Degenerate joint disease

Question 43

When does degenerative joint disease typically occur following shoulder dislocations?

Answer 43

Typically after labral and cartilaginous injuries and chronic recurrence