Caused by ‘wear and tear’ of the AC joint, the joint on the top of the shoulder that connects the scapula (shoulder blade) to the clavicle (collarbone). As the joint wears out, the ends of the bone rub, and become painful. Bone spurs may develop, causing pressure on the muscles underneath.
Common Causes
There may be an old history of an AC sprain, or other shoulder injury. Weightlifters are prone to this condition at a younger age. Often no cause is found, other than ‘wear and tear’.
Symptoms
Pain, generally on the top of the shoulder, which may radiate up to the neck, the upper arm, or the back of the shoulder. Pain is usually worsened with sleeping on the side, lifting, and reaching across the body.
Physical Findings
Tenderness at the AC joint, positive physical exam tests.
Workup
Physical exam and x-rays are diagnostic.
Non-operative Treatment
Anti-inflammatory medications, and a trial of a corticosteroid injection. Physical therapy often aggravates symptoms.
Surgical Treatment
Shoulder arthroscopy, with removal of a small portion of the end of the collarbone, so that the two bones do not rub anymore.
Injury Comment
Generally this condition slowly progresses, and non-operative treatment is of limited relief. Most of the time, the entire surgical procedure can be done arthroscopically, without a large incision, and with rapid return to full activities and pain relief.