Arthritis of the shoulder
Shoulder arthritis is inflammation of one or both of the joints in your shoulder that facilitate movement. Arthritis of the shoulder can affect the AC (acromioclavicular) joint or the glenohumeral joint or both. The AC joint is located where the collarbone (clavicle) meets the tip of the shoulder bone (acromion). The glenohumeral joint is a ball-and-socket type joint at the junction of the upper arm bone (humerus) and the shoulder blade (scapula). Symptoms of shoulder arthritis, or arthritic shoulder, range from pain and limited movement to a clicking or grinding sound upon movement.
An estimated 40 million Americans have some form of arthritis or other rheumatic condition. According to a collaborative report by the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), the Arthritis Foundation and the American College of Rheumatology, the prevalence of osteoarthritis is rising as baby boomers grow older, with osteoarthritis being second only to chronic heart disease in causing worksite disability.
There are three types of arthritis that affect the shoulder:
- Osteoarthritis – also known as “wear and tear” arthritis, this condition generally affects people over age 50. Osteoarthritis is a degenerative and possibly hereditary condition that destroys the smooth outer covering (articular cartilage) of the bone. Osteoarthritis can affect either the glenohumeral or AC joint at the shoulder.
- Rheumatoid shoulder arthritis – a systemic inflammatory condition of the joint lining of the glenohumeral joint (synovium). Rheumatoid arthritis affects multiple joints and people of all ages.
- Post-traumatic shoulder arthritis – can develop after any injury to the shoulder, such as a dislocation or fracture.
- Rotator cuff tear arthropathy - a type of arthritis in which the rotator cuff is torn and can no longer hold the head of the humerus, causing it to rub against and damage the surfaces of the bones.
- Avascular necrosis - a painful condition in which the bone cells die, resulting from disrupted blood supply to the head of the humerus. This can cause the shoulder joint to break down.