Acromioclavicular Joint Injuries


Injuries to the acromioclavicular (AC) joint are common (approximately 9% of shoulder girdle injuries) and occur most often in young men. A blow to the lateral acromion as a result of direct trauma, such as falling off a bicycle, or a superiorly directed force from the upper arm that pushes the humeral head under the acromion are typical mechanisms of AC joint injury. Injury to the AC joint is understood as a sequential loss of joint stabilizers (AC and coracoclavicular [CC] ligaments). The classification of AC joint injury reflects this anatomic progression of injury and is useful for guiding treatment. Type I and II AC joint injuries are considered incomplete lesions and may be treated conservatively with ice, rest, and immobilization, followed by physical therapy. Type IV, V, and VI injuries are complete injuries that usually require surgical intervention. The treatment of type III AC joint injuries is controversial. Currently, there is no consensus on patient selection, timing of intervention, and choice of surgical fixation. The augmented Weaver-Dunn procedure is currently the gold standard of surgical treatment of AC joint separations. In the traditional Weaver-Dunn, the AC joint is resected and the CA ligament is transferred to the end of the clavicle to provide stability in the horizontal and vertical planes. Most surgeons now add a nonbiologic or biologic augmentation. An alternative surgical intervention is anatomic CC ligament reconstruction, which is designed to closely approximate the intact state and may provide better stability.

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