Shoulder Instability​

The shoulder is an inherently unstable joint and depends on the surrounding muscles, capsule and ligaments for support and stability. These structures may be congenitally loose or damaged as a result of injury.

This can lead to excessive movement of the end of the arm bone in the socket, or if due to a high-energy injury (e.g., fall or tackle during sports), a dislocation of the joint. The latter injury may be associated with damage to the nerves and blood vessels of the upper limb, and require urgent medical attention.

In an acute injury, the following symptoms may be present:

1. Swelling
2. Numbness
3. Weakness
4. Bruising

Some people may feel instability of the shoulder joint and the sensation of the shoulder ‘popping out’, occurring with specific activities or positions of the arm, such as throwing a ball or reaching behind the body.

• Significant trauma to a previously normal joint, causing partial dislocation (subluxation) or dislocation of the shoulder joint, can lead to joint instability.
  
• Repetitive overhead motions can cause wear and tear of the joint and stretch the capsule that surrounds the shoulder joint, inherently making the joint loose and unstable.
  
• Congenital factors such as hyperlaxity syndrome can also cause a general looseness in the joint and the surrounding ligaments, tendons and muscles.

​Besides a thorough history and physical examination to establish the cause, extent and severity of the problem,
investigations such as x-rays, ultrasound scans, magnetic resonance imaging (MRI), or computed tomography (CT) scans may be done to assess its severity and/or exclude injuries to the surrounding structures. This will also help with selecting the appropriate course of treatment.

• Rest. After an acute episode of dislocation, it is important to rest the shoulder in a sling and avoid aggravating activities for the first few days.
  
• Ice and Medicine. Applying ice before and after exercise, as well as nonsteroidal anti-inflammatory drugs (NSAIDs) can help reduce the pain and swelling.
  
• Physiotherapy. Once the pain and swelling have subsided, physiotherapy for range of motion exercises and gentle strengthening can be started.

The goal of therapy is to achieve shoulder motion and stability and increase rotator cuff muscle strength. If the shoulder remains unstable despite a course of strengthening physical therapy and activity modification, surgery to stabilise the shoulder joint may be needed.