AC Joint Arthritis

AC Joint Arthritis

AC arthritis is chronic inflammation of the acromioclavicular (AC) joint, one of the four joints that work together in the complex system that makes up the shoulder. Like most cases of arthritis, AC arthritis happens when the cartilage protecting certain bones within the joint wears thin.

Recognizing AC arthritis as the unique condition that it is important when it comes to treatment. Though shoulder arthritis occurs in the same region, the conditions are not one and the same.


Acromioclavicular Joint Anatomy


Shoulder - AC joint Arthritis


Patients with AC arthritis usually complain of pain associated with shoulder motion, but neck and arm pain may also play a part, which can complicate diagnosis.

Specific movements tend to exacerbate the symptoms. A common test performed by your doctor would be to bring the affected arm across your chest. This movement compresses the AC joint and will most often recreate pain symptoms.


AC arthritis is usually osteoarthritis, the result of repeated movements that wear away cartilage in the acromioclavicular joint. Because the shoulder is used so commonly, it is not surprising that joint surface may wear thin after years of use.

However, other problems may bring on symptoms:2

Inflammatory conditions: Autoimmune diseases like rheumatoid and psoriatic arthritis can attack the AC joint.

Septic arthritis: This stems from an infection in the joint that can be transmitted via the bloodstream or by an injury delivering germs directly to the joint (a puncture, for example).

Injuries: Shoulder trauma, such as shoulder separation, may contribute to the development of AC arthritis.


AC Joint Repair with Arthrex® Dog Bone™ Button


Treatment of AC arthritis depends on the severity of symptoms and the presence of other shoulder problems including impingement syndrome, glenohumeral arthritis, and muscular injury such as a rotator cuff tear.1

If the symptoms of AC arthritis are mild to moderate, anti-inflammatory medications and physical therapy are the most common conservative measures. Your doctor may inject the AC joint with local anesthetic or steroids to see if your symptoms improve.

If the symptoms do not respond to conservative treatment, or if the pain is too severe, surgery may be necessary. An arthroscopic procedure can remove the end of the clavicle (collarbone) and allow the AC joint to fill with scar tissue.

Usually less than a centimeter of bone is removed. This allows for normal movement of the AC joint (which is minimal even in healthy shoulders) while stopping the exposed bones from rubbing together.

For an isolated AC joint resection, treatment usually lasts about eight weeks and often involves working with a physical therapist.



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