Acromioclavicular (AC) Joint Arthritis


The AC (acromioclavicular) joint is a joint in the shoulder where the collarbone (clavicle) meets the shoulder blade (scapula). Over time, the joint can wear out, leading to swelling and formation of spurs around the joint.  Shoulder joint pain, or acromoclavicular joint arthritis can be caused by injury, sports, overuse or torn muscles of the rotator cuff.  It can cause difficulty in moving the shoulder and can cause a pain when reaching across the body towards the other arm.

Why it Occurs

It can occur with aging and/ or overuse of the shoulder. It is also seen in weight lifters and other athletic individuals. Golfers can see it in usually one side only and it can result from surgery or trauma with a history of a broken clavicle bone in the area of the joint or with a torn rotator cuff.


Like arthritis at other joints in the body, it is characterized by pain and swelling, especially with activity.  Over time, the joint can wear out, leading to swelling and formation of spurs around the joint. These spurs are a symptom of the arthritis and not the primary cause of the pain. Motions which aggravate arthritis at the AC joint include reaching across the body toward the other arm. AC joint arthritis may also be present when there are rotator cuff muscle tears.


There is currently no way to replace the cartilage that is damaged by arthritis.  As a result, the primary way to control the symptoms of arthritis is to modify your activities so as not to aggravate the condition. Application of ice to the joint helps decrease pain and inflammation. Medication including aspirin, acetaminophen, and nonsteroidal drugs anti-inflammatory drugs (NSAIDs) are also used commonly. If conservative management as above fails then an injection of corticosteroids can be helpful.