• In this article we will concentrate on surgery to stabilise the ball and socket joint of the shoulder (known as the glenohumeral joint).
• Shoulder instability can be caused by a variety of things such as a traumatic injury, underlying hypermobility, shape of the bony socket, or a combination of these things.
• Depending on the pattern of instability, treatment may require surgery, physiotherapy or both.
• Surgery aims to repair the structures damaged when the shoulder is dislocated.
• In most cases, surgery can be performed arthroscopically (key hole surgery).
• If there is a larger amount of damage to the bony structures, open surgery may be required.

Why is surgery required?

The ball and socket joint (known as the glenohumeral joint) of the shoulder is a relatively shallow joint and can become unstable after major trauma. During a fall or a heavy tackle in sport, the structures that usually contribute to its stability can become torn or damaged. In more elderly patients recurrent instability is not usually a problem, but in younger patients, particularly those engaged in contact and overhead sports (rugby, football, tennis) recurrent dislocations can occur and result in significant damage to the joint and its surrounding structures.

X-ray of an acute shoulder dislocation

Which structures are damaged in shoulder instability?

To provide stability, the shoulder relies the labrum (the lip liner made of cartilage which deepens the socket); the joint capsule and ligaments, as well as the co-ordinated action of the muscles around the shoulder. In a traumatic shoulder dislocation, the humeral head (the ball) is usually dislocated anteriorly (to the front), out of the glenoid (socket of the joint). This results in tearing of the labrum and damage to the ligaments.

Labrum and glenohumeral ligaments

This may result in these structures becoming unable to maintain stability of the ball and socket joint of the shoulder, especially in certain arm positions. In some cases, there can also be an injury to the underlying bone of the socket, on its front rim. A fracture can increase the risk of ongoing instability.

Scan showing a fracture of the front and bottom edge (antero-inferior rim) of the glenoid (socket) of the right shoulder (known as a Bony Bankart injury)

Impaction fracture of the humeral head (left shoulder)

What treatments are available for shoulder instability?

The appropriate treatment for shoulder instability is dependent on a number of factors, including the type of instability, the pattern of the structures injured and the anticipated types and levels of activity that the individual wishes to undertake. In a traumatic instability, it may be necessary to repair the damaged structures with either an arthroscopic stabilisation (keyhole surgery) or open procedure.

If the dislocation has occurred without trauma, or with only minor trauma, or if the age and activity levels of the individual make further dislocation unlikely, it may be that the instability can be treated successfully with physiotherapy.

Arthroscopic view of labral damage (left)

Arthroscopic stabilisation (left)

The surgical treatment of shoulder instability involves the repair (usually by way of keyhole surgery) of the damaged tissues, commonly at the front of the shoulder, to help prevent the humeral head from dislocating.

When undergoing surgery, it is advisable to work with a physiotherapist before and after the operation, to maintain a functional range of movement and to rehabilitate to gain confidence in the shoulder.

Patient Information

Find out important information before yout treatment

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