Acute acromioclavicular injuries in adults.

The acromioclavicular joint is comprised of the articulation between the distal end of the clavicle and the acromion. It functions to anchor the clavicle to the scapula and to the shoulder girdle. The subcutaneous location of this joint makes it vulnerable to injury. It comprises approximately 9% of all injuries to the shoulder girdle. The majority of these injuries occur in males with a male to female ratio of approximately 5:1, and the most common age group affected are those in their 20s. Injuries to the acromioclavicular joint are prevalent in football, rugby, and other contact sports. Given the high incidence of acromioclavicular injuries, it is common for orthopedists, emergency physicians, and physical therapists to recognize and initiate treatment for the full spectrum of this type of injury. The current literature outlines joint biomechanics, various methods of fixation, and outcomes of both nonoperative and operative therapy. This article reviews the anatomy, biomechanics, classification of injury, fixation techniques, and outcomes.