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Acriomioclavicular Arthritis (AC Joint)


The shoulder blade and the collarbone meet at a joint called the "acromioclavicular joint," more commonly called the "AC Joint."

Occasionally the AC joint develops painful arthritis. Arthritis is a condition in which the smooth cartilage ends of bones wear out, similar to excess wear of rubber on a tire. If arthritis is bad enough, cartilage is completely worn out and bone rubs against bone, similar to a car riding only on the rims of tires with no rubber on them at all.



The shoulder blade and the
collarbone meet at the AC joint

If the AC joint develops arthritis it can be quite painful. Patients complain that pressure on the joint hurts. For example, a strap from a handbag or knapsack can put pressure on the joint and cause it to ache. Patients also report pain when reaching across their body, for example when putting on a seatbelt.


Treatment options for arthritis at this joint include pills, injections, and surgery. If surgery is recommended then it is usually performed arthroscopically.

Arthroscopic surgery uses small incisions and small tools, about the size of a pencil, to perform the procedure. All the work is visualized with a small camera, the arthroscope. The surgeon sees inside the shoulder with the arthroscope and its images are projected on a video screen.

During the procedure, the surgeon removes the rough bone ends that rub together. A section of bone about the width of one's pinky is removed. This prevents bone from rubbing on bone and relieves pain. The stability of the joint is not affected because only a minimal amount of bone is removed and the surrounding soft tissue keeps the joint aligned properly.

Often this procedure is performed at the same time as a rotator cuff repairand/or a subacromial decompression, but may be done on its own.


Arthroscopic camera and tools in the shoulder


Worn arthritic cartilage is removed

Rehabilitation after surgery will depend on whether or not other procedures were performed at the same time as the AC joint procedure. If done alone, recovery involves a moderate amount of physical therapy. Additionally, sling wear and activity restrictions are usually not necessary. If a rotator cuff repair is done during the procedure, then several months of physical therapy are generally required. Additionally, a sling is needed and activity restrictions will apply.

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