Shoulder

AC Joint Arthritis

What is AC joint arthritis?

AC joint arthritis is damage to the shiny white cartilage surfaces of the bones in the small joint at the top of your shoulder. The AC joint is located at the top of the shoulder where the scapula (shoulder blade) and the clavicle (collarbone) come together. There is cartilage between these two bones. Over time, degeneration of the AC joint can occur resulting in loss of cartilage and development of painful spurs around the joint. This degeneration results in osteoarthritis of the AC joint, similar to other joints of the body. Patients will usually have pain on top of their shoulder and pain when they bring their arm across their chest.

What causes AC arthritis?

The principle cause of AC joint arthritis is use. The cartilage becomes worn over time and eventually arthritis may occur. Another cause is an old injury to the AC joint, such as an AC joint separation. Persons who do constant overhead lifting, such as construction workers and weightlifters, are at increased risk for AC joint arthritis.

How is AC joint arthritis diagnosed?

Patients with AC joint arthritis have pain and tenderness in the front of the shoulder around the AC joint. Bringing your arm across your chest, compressing the AC joint, may increase your pain. Occasionally, there may be swelling around the AC joint. The diagnosis of AC joint arthritis can usually be made by physical examination and x-rays. X-rays usually reveal narrowing of the AC joint and bone spurs around the joint.

How is AC arthritis treated?

Treatment, initially, consists if rest and non-steroidal anti-inflammatories (NSAID’s) such as ibuprofen or prescription drugs. Cortisone, a steroidal antiinflammatory, can be injected into the AC joint if symptoms persist despite the use of nsaid’s.

What happens if surgery is necessary?

Occasionally, surgery is required when non-operative treatment fails to improve your pain. The most common surgery is distal clavicle excision. In this procedure, the end of the clavicle (collarbone) is removed leaving a space between the acromion (roof of the shoulder blade) and the cut end of the clavicle. This surgery can be done arthroscopically (through small buttonhole sized arthroscopic portals) or a small incision.