Injury to the AC joint (between the collarbone and the shoulder blade)

The AC joint is a common location for sports injuries, usually resulting from a person falling on their shoulder.

The AC joint (acromioclavicular joint) is located in between the collarbone and the upper part of the shoulder blade. There are several degrees of severity for injuries to the AC joint, and most can be treated conservatively (without an operation). Following an injury to the AC joint there will often be swelling and pain above the joint. An X-ray examination will in most cases be able to determine the severity of the injury by comparing the injured side with the uninjured side.


The initial treatment involves pain relief and limiting movement of the injured site for a short period. You can apply ice to the injured area, but not directly on the skin. Place the arm in a sling. Following this, it is important to increase shoulder activity gradually. The activity should not be very painful. Some discomfort is okay, but bear in mind that there is a healing process going on. The pain will decrease as time goes by. You can return to sporting activities once movement and strength have returned to normal and there is no pain involved in performing sport specific movements. If pain and decreased function persist, surgery may be necessary.


The likelihood of a complete recovery is high. Following an injury to the AC joint, some people may end up with a slight bump where the shoulder blade attaches to the collarbone. This is completely normal and often unproblematic. It is also normal to feel friction or hear «cracking» sounds in the joint. This is usually not a problem if it is not painful.

In some cases, injuries to the AC joint can lead to joint osteoarthritis. This can be treated with cortisone injections and in some cases, surgery.