Shoulder Dislocation

Shoulder is the most mobile joint in the human body, having the widest range of movements. However, the free mobility comes at a cost of instability. Hence, the shoulder is also the most common joint to become dislocated. Let’s have an overview of various aspects of a shoulder dislocation.

What is a dislocation?

The ends of two bones form a joint. ’Dislocation’ is when one of the two bones forming a joint gets completely displaced from its anatomical position. When there is only partial displacement, it's called a ‘subluxation’.

What exactly happens in a shoulder dislocation?

The shoulder is a ‘ball & socket’ type of joint formed by a ball of the arm bone (humerus) and the socket (glenoid) of the shoulder blade (scapula). But the socket is not deep enough to keep the ball in place. Various structures help maintain joint stability during movement.

The socket is lined by ‘labrum’, a rim (boundary) of fibrocartilage, which is also the anchor point for the joint capsule (envelope). This is one of the most crucial but weak points of the joint. When the shoulder dislocates for the first time, it tears the labrum off the socket bone. The name given to this tear is ‘Bankart lesion’.

Even after the joint is reduced back in its position, the labrum does not heal well and acts as a weak point for repeated episodes of dislocation. Also, a torn labrum can rarely take a small piece of bone away from the socket, known as ‘Bony Bankart lesion’.

During dislocation, the ball (head of humerus) gets impacted against the sharp edge of the socket, and that forms a depression on the ball called ‘Hill-Sachs lesion’.

How to understand if someone has suffered a shoulder dislocation?

Rohit Sharma's Shoulder Injury

Ollie Pope's Shoulder Dislocation

Shoulder dislocation happens for the first time after a significant trauma such as a road traffic accident, a fall from height, or high-velocity trauma while playing contact sports. The successive episodes of dislocation may occur without significant injury. In recurrent dislocations, it can even happen during sleep.

Symptoms of dislocation are:

• Sudden onset of unbearable shoulder pain immediately after the injury

• Inability to move the arm at all

• Squaring or flattening of the round contour of the shoulder

• Numbness or tingling in the arm

  
  

What are the various types of shoulder dislocation?

There are three main types

1. Anterior

• The ball (head of the humerus) gets displaced forward, in front of the socket (glenoid).

• This is the most common type, amounting to around 96% of all shoulder dislocations.

• Typically results from a fall on an outstretched hand or a direct blow in throwing position.

• It can be easily diagnosed by clinical findings and a radiograph (X-ray).

  
  

  

  
  

2. Posterior

• The ball moves backwards, behind the socket

• Less common (3%), often caused by seizures, electrocution

• Can be missed out on standard X-rays if not looked for carefully

3. Inferior (luxatio erecta)

• The rarest type (<1%)

• The ball moves downwards, below the socket.

• Results from extreme force that pulls the arm upwards. Dislocation is obvious on X-ray.

  
  

Why does a shoulder dislocation happen?

Various risk factors can contribute to the issue.

1) Trauma

• Falls onto an outstretched hand

• Sports injuries (especially contact sports like football or rugby). The throwing position (arm abducted & externally rotated) is most prone to get an anterior dislocation.

• Road traffic accidents

2) Congenital Conditions:

Some individuals have excessively loose ligaments since birth, known as ‘generalised ligamentous laxity’, increasing the risk of dislocation even without significant trauma. This could be a physiological condition or part of a syndrome, such as Ehlers-Danlos syndrome.

3) Age and Gender:

• Young boys under the age of 25 are most commonly affected due to their higher activity levels and participation in competitive sports.

• Dislocations in the older age group are a different entity and are associated with rotator cuff tendon tear.

  
  

What happens if it is not treated in time? What is a ‘Recurrent Dislocation’?

When the same shoulder dislocates 3 or more times, it is called a ‘recurrent dislocation’. With every successive episode of dislocation, the labrum quality deteriorates and the bone of the ball & socket starts to get eroded.

As the bone loss of the socket increases, the ball starts dislocating easily, even without a significant trauma or fall. Patients tend to dislocate their shoulders even during sleep as the muscles around the shoulder are relaxed.

How is a dislocation and recurrent instability diagnosed?

It is always a combination of clinical examination and radiological modalities

A) Physical Examination:

• Identifying a dislocated shoulder is quite straightforward. Acute onset of severe pain, inability to move the shoulder at all, the arm by the side of the body supported by the other hand and squaring of the round shoulder contour are characteristic of a dislocation.

• Neuro-vascular assessment is essential to check for axillary nerve or blood vessel injury.

• In case of a recurrent instability, certain special clinical tests like the Apprehension test, the Sulcus sign, and the Load and shift test help in making a diagnosis.

• Generalised ligamentous laxity should be evaluated in every patient using the Beighton score.

B) Radiology:

• X-rays are the go-to investigation in acute dislocation episodes. They confirm the type and direction of dislocation and rule out associated fractures.

• Bony Bankart and Hill-Sach lesions can be seen on special X-ray views.

• MRI is the gold standard to diagnose the labral injury (Bankart lesion).

• In case of recurrent dislocations, CT scan is a must to detect the extent of bone loss and decide on definitive management.

  
  

What is the treatment for an acute shoulder dislocation?

First and foremost, the thing is to reduce the dislocated joint. The method of reduction depends on the type of dislocation and associated fractures. The most commonly followed treatment protocol is:

1. Closed Reduction

Your orthopaedic doctor gently manoeuvres the ball back into the socket. It is usually done under an analgesic injection. Rarely, if the patient is apprehensive and non-compliant, short general anaesthesia may be required.

Pain relief is immediate once the joint is back in place. Any forceful reduction method should be avoided as it can lead to a fracture.

2. Immobilisation

After reduction, the shoulder is often immobilised in a shoulder immobiliser sling for 3 weeks.

3. Physical Therapy/Physiotherapy

Intermittent elbow and wrist movements are encouraged throughout immobilisation. After 3 weeks, gradual exercises are started to regain the complete range of shoulder movements.

This is followed by strengthening of the muscles around the shoulder joint. Return to contact sports, heavy activities need to be avoided for at least 3 months.

4. Surgical Treatment

This is rarely required in an acute episode in the following conditions:

• Inability to reduce the joint even under general anaesthesia

• Associated displaced fracture of ball (needs fixation either by anchors or plate-screws

• Associated bony lesion of the socket (Bony Bankart)

The treatment after a single episode of shoulder dislocation is essentially conservative. Only when there are recurrent dislocations happening is a definitive surgical management required.

What is the treatment of recurrent shoulder dislocation?

Surgery is required in order to restore the anatomy. Indications and choice of surgical procedure depend on multiple factors like severity of bone loss of the socket, dimensions of Hill-Sachs lesion, patient’s age, occupation, hand dominance, involvement in sports or heavy labour activities and functional demands.

Bankart Tear Repair

Bone Block Cerclage

Latarjet

Common surgical procedures include:

• Bankart repair: The torn labrum is repaired (arthroscopically) when the bone loss is <15%

• Remplissage: infraspinatus tendon is fixed into the Hill-Sach defect on the ball (arthroscopic) when the lesion is off-track

• Bone block cerclage: bone loss of the socket is restored with a bone graft (arthroscopic) when the glenoid bone loss is sub-critical (15-20%)

• Latarjet procedure: coracoid process is cut and attached in front of the socket with screws when the socket bone loss is critical i.e. >20% (open/arthroscopic)

  
  

What is the recovery timeline after surgery?

Complete recovery requires strict adherence to supervised rehabilitation exercises and a gradual return to activity. Physiotherapy plays a crucial role in recovery. Typically, the shoulder is immobilised in an arm sling support for 2-3 weeks post-surgery. Although there are different protocols following various surgeries, patients are expected to regain a complete range of movements by 3 months and considerable strength by 6-9 months. Return to competitive sports or heavy activities can be resumed at one year, provided recovery is satisfactory.

How to prevent a shoulder dislocation or re-dislocation?

The following measures would be helpful:

1. Strengthening of the scapula and shoulder muscles

2. Maintain flexibility. Follow a stretching routine before workouts or sports.

3. Avoid overhead or throwing activities if the shoulder is prone to dislocation

4. Following proper techniques and using protective gear

4. Avoid a re-injury: Return to sports only when fully recovered. Gradually increase activity levels under proper guidance.

5. Consult an orthopaedic surgeon immediately when the first episode of dislocation occurs.

To conclude:

Shoulder dislocation is a serious injury that should not be ignored. While it is common, prompt medical attention, expert treatment, and a structured rehabilitation can ensure full recovery and reduce the risk of recurrence. Remember that every episode of dislocation will cause more & more damage to your shoulder!

Get to know the Doctor