What is Shoulder Arthritis?
Arthritis is the process of loss of joint cartilage. The cartilage that lines a joint allows for smooth pain free movement. When there is loss of this protective coating the joint no longer functions normally and becomes painful. In addition, there is usually restricted motion because of extra bone (osteophytes) that forms in an attempt to heal the damaged cartilage.
Avascular necrosis of the humeral head. Note the ball has collapsed and is no longer round.
Causes
There are several causes of shoulder arthritis. It may be age related osteoarthritis from wear and tear or an inflammatory form of arthritis such as rheumatoid arthritis. Osteoarthritis may have a genetic component but also occurs as a result of trauma. Recurrent shoulder dislocations can lead to osteoarthritis as a result of repeated insults to the cartilage and soft tissues with each dislocation. A major trauma to the humeral head (the ball) damages the cartilage and can create a deformity if there is a fracture. With a fracture, the blood supply to the humeral head can also be affected leading to death of the bone (avascular necrosis) at the joint and arthritis as the dead bone collapses.
Avascular necrosis of the humeral head. Note the ball has collapsed and is no longer round.
Surgical Treatment
Non-operative treatment options are the first line of therapy.
Operative options include a shoulder arthroscopy and clean up or a shoulder replacement surgery. Shoulder arthroscopy has a limited role in the setting of osteoarthritis, but is occasionally used in younger patients with significant arthritis who are trying to delay shoulder replacement and need to continue doing physical labour activities. This is a temporary solution and may or may not be effective.