Shoulder > Acromioclavicular Joint Arthrtis (AC Arthritis)

What is the acromioclavicular joint?

The top, or roof, of your shoulder blade is called the acromion. Your collarbone, called the clavicle, connects to the shoulder blade at the acromioclavicular (AC) joint and to your chest bone, called the sternum, at the sternoclavicular (SC) joint. Ligaments, in general, function as joint stabilizers – attaching at either end to bone. One set of ligaments help to stabilize the AC joint. Ligamentous attachments are found both on the distal clavicle and acromion as well as the prominent coracoid process – a bony prominence located on the front of the shoulder blade, or scapula, and directly below the AC joint. The articulating surfaces of the AC joint are covered with hyalin cartilage. Bursa sacs and synovial fluid also help to ensure smooth coordinated movement between the AC joint, glenohumeral (shoulder) joint and the under/overlying complex of shoulder tendons.

The term AC Arthritis describes a process of gradual degeneration in your AC (acromioclavicular) joint that worsens with wear-and-tear over a period of many years. Overuse can break down the articular cartilage surfaces, causing your collarbone and shoulder blade to grind against each other. This commonly causes the onset of arthritis in the AC joint. Some weightlifter's develop a painful AC Joint associated with loss of clavical bone in the AC Joint. This is called Weightlifter's shoulder.


Repeated overhead activities are the most common causes of AC Arthritis.

Considerations and Treatments  

AC Arthritits often can be treated non-surgically with activity modification, NSAID'S and a cortisone injection. Surgery usually is not considered until you have tried non-operative treatment for at least six months. If your symptoms do not become less painful, surgery to remove part of your collarbone can help to restore full function in your shoulder.

Orthopedic Evaluation [top]

There usually are three parts to an orthopedic evaluation: medical history, a physical examination, and tests that your doctor may order.


Your physician likely will ask about your activities or any traumatic event that may explain your shoulder pain. You will probably be asked when the soreness or pain began. If you have had any prior shoulder injuries, your physician will ask about treatments you have tried in the past. You will probably be asked whether you have been able to continue participating in activities since you noticed the pain. Physicians also typically ask about other conditions, such as arthritis, diabetes, and allergies, and medications currently being taken. You may also be asked about your physical and athletic goals – information that will help your physician decide what treatment might be best for you in achieving those goals.


To diagnose AC Arthritis, physicians usually press the areas around the front and back of your shoulder to test for tenderness around the AC (acromioclavicular) joint. You may be asked to hold your arm up at shoulder height and move it inward across your chest to test the stability of the AC joint. You also may be asked to hold your arms straight out in front of you with your palms facing down and your hands about six inches apart. If you experience pain as you resist your physician pushing your arms down, you may have damage in your AC joint.

Tests [top]

X-rays may be given to check for fractures and see the position of your collarbone and shoulder blade. You may be asked to hold weights in your hands during the X-rays to slightly stress the AC joint, which provides an image for diagnosing instability. X-rays can reveal any bone spurs or cysts in your AC joint.

Rest, Medication, Physical Therapy
Distal Clavicle Excision

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