Instability of the shoulder can occur for a variety of reasons.
Depending on the pattern of instabilty treatment may require surgery, physiotherapy or both.
Surgery aims to repair the structures damaged when the shoulder is dislocated.
Most cases can be performed arthroscopically (key hole surgery).
If there is a lager amount of damage to the bony structures open surgery may be required.
Why is surgery required ?
The shoulder ( a shallow ball and socket joint) can become unstable after major trauma such as during a fall or tackle where the structures that normally control its stability are torn. 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
What structures are damaged in shoulder instability ?
The shoulder relies on both anatomical structures, such as the labrum (a ring of cartilage that deepens the socket), joint capsule and ligaments as well as co-ordianted action of the muscles around the shoulder to provide stability. In a traumatic shoulder dislocation the humeral head (ball) is usually dislocated anteriorly (to he front) out of the glenoid (joint socket). 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 help contain the head in the glenoid in certain arm positions. In some cases the anterior rim of the glenoid can become fractured and this can exacerbate the problem
Fracture of the front of the glenoid (Bony Bankart lesion)
Impaction fracture of the humeral head (left shoulder)
What treatments are available for shoulder instability ?
The appropriate treatment for shoulder instability is dependant on a number of factors including the type of instability, the pattern of 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.
Article written by
Mr Angus Robertson
Consultant Knee Surgeon and Shoulder Surgeon, Cardiff
Last updated 03/08/10