Osteoarthritis, also known as “wear and tear” arthritis, is a condition that erodes the smooth lining (articular cartilage) of a joint. As the cartilage wears away, it becomes frayed and rough, and the protective space between the bones decreases. During movement, the bones of the shoulder joint rub against each other, causing pain.
Osteoarthritis usually affects people over 50 years of age and is common in the glenohumeral (ball and socket) shoulder joint and the acromioclavicular (end of collar bone) joint.
There are other forms of arthritis that can affect the shoulder joint. This includes rheumatoid, post-traumatic and rotator cuff tear arthritis.
Rheumatoid arthritis is an inflammatory process that affects the lining of the joint causing swelling and pain. Post-traumatic arthritis can occur after fractures of the upper arm bone or dislocation of the shoulder joint.
Rotator cuff tear arthritis occurs after large, long standing rotator cuff tendon tears. The torn rotator cuff can no longer hold the ball of joint firming in the socket, causing it to rub up and down. This can damage the surfaces of the joint, causing arthritis in shoulder to develop.