What are AC joint problems?
The AC joint, or acromioclavicular joint, is the junction where the clavicle, or collarbone, attaches to the shoulder blade. This joint is a small bump that can be felt over the top of the shoulder. The AC joint is stabilized by ligaments that can be injured by a direct fall onto the front or top of the shoulder. This type of injury is called an AC joint sprain or separation. The AC joint can also undergo degeneration over time, especially in long-term weight lifters or people who do a lot of overhead work. This is known as degenerative joint disease of the AC joint, or AC joint arthritis.
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What symptoms do they cause?
Arthritis or degeneration of the AC joint is usually felt as pain at the end of the collarbone or generalized soreness in the front and top of the shoulder. An AC joint sprain usually occurs after a fall or blow to the front/top of the shoulder and causes acute pain. In a severe sprain, the ligaments of the AC joint can tear, and the end of the collarbone will become more prominent, resulting in a noticeable bump.
How are they diagnosed?
Although AC joint problems can usually be diagnosed by a careful physician examination, X-rays are also useful to evaluate the joint. In arthritis or degeneration, bone spurs and narrowing of the joint is seen. In sprains, the physician can measure how much the end of the collarbone is elevated or lifted up, which is important in determining a treatment plan.
How are they treated?
AC joint arthritis can be treated with changes in activity, anti-inflammatories, physical therapy and sometimes, injections. In severe cases, surgery may be done to remove bone spurs and the irregular joint surface. Most AC joint sprains are treated with rest, ice and short-term sling use. When an AC joint sprain is severe and there is considerable elevation of the collarbone, surgery may be needed to repair the ligaments and restore joint alignment.