[7] Shoulder Dislocation Flashcards
Why are dislocations of the shoulder common?
Because the shoulder is a highly mobile joint, which sacrifices stability for an increased range of movement
What can shoulder dislocations lead to if not managed correctly?
Chronic joint instability and pain
What is the most common type of shoulder dislocation?
Anteroinferior (usually just termed ‘anterior’)
What % of shoulder dislocations are anteroinferior?
Around 95%
What are the less common types of shoulder dislocations?
- Posterior
- Inferior
What classically causes an anterior shoulder dislocation?
Force being applied to an extended, abducted, and externally rotated humerus
What classically causes posterior dislocations?
Seizures or electrocution
How can posterior dislocations occur through trauma?
Direct blow to the anterior shoulder or force through a flexed, adducted arm
Why are posterior dislocations important diagnostically?
They are the most commonly missed dislocation of the shoulder, especially as the radiographic evidence of them can be subtle
How do shoulder dislocations present?
- Painful shoulder
- Acutely reduced mobility
- Feeling of instability
- Reluctance to move affected limb
What may be found on examination in a dislocated shoulder?
- Asymmetry with the contralateral side
- Loss of shoulder contours
- Anterior buldge from head of humerus
What is it important to assess in a should dislocation?
Neurovascular status of the arm
Which nerves are most likely to be compromised in a shoulder dislocation?
Axillary and suprascapular nerves
What bony injuries are commonly associated with shoulder dislocations?
- Bony Bankart lesions
- Hills-Sachs defects
- Fractures of greater tuberosity and surgical neck of humerus
What are bony Bankart lesions?
Fractures of the anterior inferior glenoid bone
Who are Bankart lesions most commony present in?
Those with recurrent dislocations
What are Hills-Sachs lesions?
Impaction injuries to the chondral surface of the posterior and superior portions of the humeral head
What % of traumatic dislocations are Hills-Sachs defects present in?
Approx 80%
What labral and ligamentous injuries can be associated with shoulder dislocations?
- Soft Bankart lesions
- Glenohumeral ligament avulsion
- Rotator cuff injuries
What are soft Bankart lesions?
Avulsions of the anterior labrum and inferior glenohumeral ligament
What % of younger shoulder dislocation patients have at least 1 rotator cuff tear?
Around 1/3
What forms the bulk of investigation for shoulder dislocations?
Imaging
What imaging is required in shoulder dislocation?
A trauma series of plain radiographs
What does a shoulder trauma series of plain radiographs consist of?
Anterior-posterior, Y-scapular, and axial views
How does a trauma series confirm an anterior dislocation of the shoulder?
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
What x-ray finding suggests a posterior shoulder dislocation?
The ‘light bulb sign’
What produces the ‘light-bulb’ sign in posterior dislocations?
The humerus is fixed in internal rotation
Which x-ray view is useful for differentiating between anterior and posterior dislocations?
Y view
What investigation should be performed if labral and rotator cuff injuries are suspected?
MRI of the shoulder
What should the immediate management of shoulder dislocations involve?
- A to E assessment
- Stabilisation of injury
- Examination for other injuries
- Good, appropriate analgesia
Why is A to E assessment important in shoulder dislocation?
As dislocations frequently occur following trauma
How should shoulder dislocations be reduced?
Closed reduction, such as Hippocratic method
This should be performed by a trained specialist, involving orthopaedics early before attempting reduction
When should neurovascular status be assessed in shoulder dislocation?
Pre- and post-reduction
What might a failed closed shoulder dislocation reduction warrent?
Attempted manipulation under anaesthesia in theatres
How should a shoulder dislocation be managed once reduced?
Place arm in broad-arm sling
How long should the arm be immobilised after shoulder dislocation?
Typically 2 weeks for anterior dislocation, longer for posterior dislocations
Do all shoulder dislocations require physiotherapy?
Yes
What is the aim of physiotherapy following shoulder dislocations?
Restore range of movement, functionality, and to strengthen the rotator cuff and pericapsular musculature
When might further surgical treatment be required in shoulder dislocations?
If there is recurrent pain, instability, large Hills-Sachs defects, or large (bony) Bankart lesions
What complications might arise from a shoulder dislocation despite treatment?
- Chronic pain
- Limited mobility
- Stiffness
- Recurrence
Is recurrence common following a shoulder dislocation?
Relatively, particularly in those who continue high risk activities
What are the common complications for shoulder dislocations?
- Adhesive capsulitis
- Nerve damage
- Rotator cuff injury
- Degenerate joint disease
When does degenerative joint disease typically occur following shoulder dislocations?
Typically after labral and cartilaginous injuries and chronic recurrence
