The main part of the shoulder girdle is the ball and socket joint known as the gleno humeral joint which is located at the top of the arm bone. The ball of this joint is about three times larger than the smaller saucer shaped socket. This makes the shoulder the most mobile joint in the body. The joint is stabilised by a deep lip or labrum of specialised cartilage around the socket and further stabilised by a complex array of fine ligaments and a tube of tendons all of which hold the ball firmly onto the socket. This tube of tendons is known as the rotator cuff.
The gleno humeral joint, because of its small socket, large ball, and enormous mobility, is an inherently unstable joint. One of the commonest injuries sustained is a dislocation.
Sitting above the ball and socket/gleno humeral joint are two other joints: the subacromial joint and the acromion-clavicular joint. The latter is where the collar bone/clavicle meets the shoulder blade acromion. This is stabilised by ligaments and within it is a specialised cartilage/meniscus. The joint can be damaged by trauma and over use.
The subacromial joint is the space between the tip of the shoulder blade, the acromion and the underlying rotator cuff tendons. This joint is probably the commonest cause of shoulder pain with patients frequently experiencing inflammation in the joint with pinching or tearing of the tendon a condition known as subacromial impingement syndrome.
Adhesive capsulitis is a disorder in which the shoulder capsule and the connective tissue surrounding the gleno humeral joint of the shoulder become inflamed and stiff greatly restricting motion causing severe pain. The exact cause of the condition is unknown and without treatment; symptoms and signs may last for up to three years. This is associated with trauma, some surgeries and diabetes. It rarely affects people under the age of 40. Treatment is almost always non operative, and we would normally utilize a combination of hydro dilatation injections performed under ultrasound guidance in outpatients, and physiotherapy. This treatment programme results in 80% good or excellent results with the injections being administered at fortnightly intervals. A small percentage of patients who do not have a successful response to this recently developed treatment will either continue with other conservative measures or may opt for an arthroscopic release.
The ligaments of this joint can be damaged as a result of violent impact, normally by a fall onto the tip of the shoulder.
Most commonly performed surgery: ACJ stabilisation.
Arthritis can affect the bones in the joint, causing pain, inhibited movement and degeneration of the joint.
Most commonly performed surgery: Arthroscopic excision ACJ arthroplasty.
The tendon of the shoulder joint can get torn as a result of trauma or chronic wear and tear.
Most commonly performed surgery: subacromial decompression.
The tendons of the shoulder joint can get torn as a result of a high impact, or chronic wear and tear.
Most commonly performed surgery: rotator cuff repair.