The effective treatment of injury to the acromioclavicular joint requires knowledge of the relevant anatomy and the pathoanatomy of a variety of injury patterns. The six-part classification system facilitates the understanding of the underlying pathoanatomy. Insight into the natural history of acromioclavicular joint injury is crucial to the success of any treatment program. Surgical reconstruction should be reserved for patients with grade IV, V, and VI lesions or those with lower grade lesions that have become chronically symptomatic. If the decision is made to proceed with surgical reconstruction, I prefer coracoclavicular fixation, over-drilling the clavicle, and use of an AO 6.5-mm cancellous lag screw to maintain reduction of the clavicle, followed by careful repair of the overlying soft tissues.