Acromioclavicular joint dislocations occur when falling on the outer tip of the shoulder. The joint between the clavicle and the acromion process of the scapula is disruptured. Football and hockey players are at risk, even with shoulder pads. A variety of ligaments may tear leading to pain and varying degrees of deformity and weakness.

Most cases heal sufficiently with rest and physical therapy. Persistent pain and severe cases of grater deformity and torn muscles may require surgical reconstruction. Lesser degrees of injury and instability may be followed by arthritis of the acromioclavicular joint.

When anti-inflammatory medication is insufficient, arthroscopic surgery is a useful alternative.