Shoulder arthritis results in inflammation which causes pain and stiffness in the joint. The shoulder girdle is made up of the shoulder blade (scapula), clavicle and the humerus. There are two joints. The main joint is between the head of the humerus and the shoulder blade. This forms a ball and socket type joint. There also is a joint between the outer end of the scapula and the clavicle – the acromioclavicular joint.
With ageing, it is common to experience some wear and tear changes in the acromioclavicular joint. This is felt as discomfort at the top of the shoulder region.
Arthritis of the shoulder joint itself occurs in several forms. Osteoarthritis results in loss of the cartilage which lines the joint surfaces. Once the smooth layer of tissue has worn away, the exposed surfaces of the bones rub together and cause pain.
Rheumatoid arthritis is an inflammatory condition that can affect multiple joints. The soft tissues are often swollen and inflamed. Medical treatments in recent years have reduced the incidence of joint degeneration in rheumatoid disease.
Some patients may develop degenerative changes in their shoulder joint as a consequence of previous trauma. They may have had fractures extending into the joint surface, which can damage the cartilage and result in the development of arthritis.
The rotator cuff tendons and muscles help to hold the humeral head in the socket. If these tendons have become worn and torn, patients may have abnormal movement of the shoulder joint. The change in biomechanics results in the shoulder joint wearing out and the development of arthritis.
The other main cause for shoulder arthritis is avascular necrosis. This is a condition where the blood supply to the humeral head is disrupted. This can happen for multiple reasons. It can be seen following trauma where the patient may have suffered a fracture. It may be seen in patients taking heavy doses of steroids or in cases of high alcohol consumption.
Pain and stiffness are the two main features that patients present with when they develop shoulder arthritis.
X-rays are usually the first line of investigation. In most cases these will demonstrate if there have been significant degenerative changes in the joint surface.
Initial treatment aims to control the discomfort. Patients may have to modify their activities to limit irritation. Regular simple anti-inflammatory medication and analgesia may control symptoms.
If the symptoms cannot be controlled with pain relief and activity modification, surgical options may be considered. In some cases, a shoulder arthroscopy may provide some relief. Arthroscopy allows the surgeon to view the inside of the joint through small keyhole incisions. Frayed or damage tissue can be removed.
If the symptoms are severe enough, a shoulder replacement may be recommended. There are several forms of joint replacement. In some cases, only the head of the humerus is resurfaced or replaced. In other instances, both sides of the joint may require a replacement.
Arthritis of the acromioclavicular joint is often treated with an excision of the outer end of the clavicle.