Acromioclavicular (AC) joint separation is a common shoulder injury, representing up to 9% of all shoulder injuries. The majority of AC injuries (44%) occur in people in their twenties and are five times more common in men than in women. They are especially numerous in younger patients participating in contact sports and represent 15%, 20%, and 41% of shoulder injuries in hockey, skiing, and American football, respectively. The most common mechanism of injury is by direct contact applied directly over the superolateral border of the shoulder while the humerus is in the adducted position