The shoulder joint is like a large golf ball sitting on a small tee. This unconstrained structural pattern affords mobility in several directions. However, for the same reason, this shallow ball-and-socket joint ( the glenohumeral joint) is the most frequently dislocated major joint in the human body. In most instances, the shoulder dislocates as the upper arm bone (humerus) comes forward out of the joint. Backward dislocation is far less common.
Dislocations are treated by replacing the shoulder back into position and immobilizing it in a sling for a few weeks. This is usually successfully done under mild sedation, but sometimes a general anesthetic with the patient asleep is preferred. Occasionally surgery is required to relocate the joint back into its normal position.
Sometimes a tendency to experience further dislocations may develop, even without much force, following the first dislocation. This is one pattern of an unstable shoulder. The problem usually occurs because the capsule surrounding the joint has been stretched by the dislocation, or part of the labrum (the thickened tissue that surrounds and deepens the socket) has been torn off from the bone, thus making the joint less stable. Most of such cases require surgery. Every time the shoulder dislocates it causes some damage to the ball and/or socket. It is thus advisable to correct this problem as soon as possible after the second dislocation. Surgery can be done either arthroscopically or in some select cases by mini open methods.
Either way, the aim is to repair the shoulder damage by reattaching the torn labrum to the bone, and by tightening the stretched capsule lining the joint.
Often athletes or heavy manual labourers involved in overhead or throwing activities develop a pain whilst stressing the joint i.e. during certain stages of the throwing or overhead action. The ball of the shoulder might just partially slip out and sit back again in such cases – another pattern of an unstable shoulder. Such shoulders often benefit from an arthroscopic repair of the torn tissue causing the problem.
Some patients have their shoulders slipping out all the time without any prior injury. They are inherently lax. Such patients benefit from structured rehabilitation regimes.
Following surgery on an unstable shoulder patients stay for a day in hospital. They use a sling for 3 weeks. Range of motion exercises follow over the next 3 weeks. The shoulder regains its strength over a couple of months. Scars are minimal and it is virtually a painless surgery. Patients return to normal activities within a month and sportsmen return to overhead activities in 6-8 weeks.