The acromioclavicular joint is commonly affected by traumatic and degenerative conditions. Most injuries are due to direct trauma, such as a fall on the shoulder. Six types of acromioclavicular sprains and three types of distal clavicle fractures have been described in adults. Although there is general agreement on treatment of type I, II, IV, V, and VI acromioclavicular injuries, the treatment of type III injuries remains controversial. Studies have shown no distinct advantage for surgical reconstruction over nonoperative treatment. Because type II distal clavicle fractures are prone to nonunion, operative fixation may be advisable to avoid this complication.