Shoulder dislocation or instability

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The shoulder is the most flexible and mobile joint in the body. This makes the shoulder vulnerable injury and dislocation.

The shoulder is a ball and socket joint. It has a very shallow bony socket called the glenoid and 50% of the depth of the joint is made up of a soft tissue labrum. The ball or humeral head is held in position by this labrum, ligaments and tendons.

In a dislocation these structures are damaged making the shoulder chronically unstable and prone to re-dislocation.
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Your shoulder has numerous muscles and tendons controlling movement and stability of the shoulder. Courtesy: Shoulderdoc.co.uk
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Dislocation. Courtesy: https://orthoinfo.aaos.org/en/diseases--conditions/slap- tears/
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X-ray image of glenohumeral (GH) dislocation.

Causes

The most common dislocation (97% of dislocations) is an anterior or forward dislocation of the shoulder. The arm is often in a position of abduction and external rotation (above the head and turned out).

Diagnosis

After a thorough history and examination with your surgeon investigations such as an X-ray and MRI are often required to confirm the structures injured and the appropriate management plan can be implemented.

Management

There is an inverse relationship between age and re-dislocation rates. The younger the patient the higher the re-dislocation rate. It is therefore recommended for younger patients undergo surgery to repair the labral tear and prevent recurrent dislocations. Patients over 50 are more likely to tear their rotator cuff with a dislocation.

Operative management

The operation is arthroscopic ‘key hole’ surgery and the labrum is repaired. This is performed under general anaesthetic with you asleep and can be performed as a day procedure.

If there is a bony deficiency due to the injury or the arthroscopic repair has failed a Laterjet procedure can be performed using a bone block.
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Labrum repair
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Non operative management

Non operative treatment is appropriate in older patients or those who have not injured the labrum. A course of rehabilitation is indicated and activity modification to prevent further dislocations.

Risks of surgery (complications)

General: Wound infection, pain, haematoma and bleeding.
Specific to shoulder surgery: Re-dislocation requiring more surgery (Laterjet: Bony procedure), restricted movement/ stiffness, nerve injury resulting in weakness or numbness in the upper limb (very rare). DVT, Stroke (very rare).

References:
Hospital for special surgery. JAAOS Arthrex website.
3rd Edition. Australian Orthopaedic Association Patient information.
See the most frequently asked questions about shoulders.
or download a pdf version of this page.
Also see the Related links on this page.