Arthritis is a chronic degenerative disorder, which results in the softening and disintegration of the cartilage that lines the joint surface. It is also accompanied by the formation of new, but abnormal, cartilage and bone at the margins of the joint (osteophytes) as well as scarring of the capsule which surrounds the glenohumeral joint of the shoulder. In advanced cases there can be a loss of bone affecting both the humeral head (ball) and glenoid (socket). The affect of all these changes is that the previously smooth shoulder becomes rough such that shoulder stiffness and pain can develop.
The pain associated with osteoarthritis is often described as a deep ache within the shoulder, which is initially made worse by movement and eased by rest. As the condition deteriorates, the pain may also be felt even when at rest and at night, such that sleep is affected. Locking and ‘clunking’ of the joint may be noticed by those affected and restrictions in the range of shoulder movement and weakness may also occur.
Causes & Risk factors
There are several different types of arthritis of the shoulder but the most common is primary osteoarthritis, which is a degenerative condition with no obvious cause. If arthritis develops as a result of another condition it is called secondary. Examples of this form of arthritis include:
- Post traumatic arthritis (as occurs following a fracture)
- Rotator cuff tear arthropathy (following a previous massive non-repairable rotator cuff tear)
- Instability arthropathy (following recurrent shoulder instability / dislocations)
- Avascular necrosis (bone death caused by the loss of its blood supply)
- Rheumatoid arthritis secondary to chronic inflammatory joint disease.
- Sero-negative inflammatory arthropathy
The diagnosis of shoulder arthritis is largely made following a history and examination however it is confirmed by x-rays which reveal irregular joint surfaces, osteophytes and possibly bone loss. In order to gain clarification about the quality of the surrounding rotator cuff tendons an Ultrasound or MRI scan may be organised and if there is evidence of significant bone loss secondary to the arthritis, a CT scan may also be requested.
The treatment of shoulder arthritis is always tailored to the particular patient.
- Rest, activity modification, pain relief and physiotherapy can all give good benefit, particularly in the early stages of the disease. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibruprofen can help control the pain but should only be used regularly under the guidance of your General Practitioner.
- Physiotherapy can prove beneficial in the early stages of the disease and can help maintain motion and strength to the rotator cuff tendons. It is however, less effective in advanced disease and may actually exacerbate the pain.
- Injection treatments can occasionally have a role. Corticosteroid injections directly into the glenohumeral joint can improve pain however the affect is always temporary and multiple injections can have a deleterious affect on the shoulder. Other injections, such as hyaluronic acid can be used. This type of injection is used to replace the natural joint fluid that is lost in the disease process. If successful, pain, the quality and the range of shoulder movement can also be increased.
- Arthroscopic debridement; this is a keyhole surgical procedure in which the severity of the cartilage damage can be assessed and if appropriate, any loose cartilage can be removed which might otherwise be aggravating the joint. Loose bodies and osteophytes can also be removed and if necessary a tight and contracted capsule can be released to allow greater movement. However, if the disease is too advanced, then a shoulder replacement will be necessary.
- Shoulder replacement; A shoulder replacement can come in many different designs. If only the humeral head (the ball) is replaced then the operation is referred to as a Hemi-arthroplasty. If the glenoid (the socket) is also replaced, then this is referred to as a Total Shoulder Replacement. When replacing the humeral head (ball) a choice will be made as to whether a stemmed implant is used or alternatively a humeral head resurfacing may be undertaken. The choice of implant will be made based on the nature of your disease and on what implant will give you the best clinical result.