Acromioclavicular Separation

Overview

AC separation is the term used to describe a traumatic injury of the AC joint (between the clavicle and the scapula). A shoulder separation is different than a shoulder dislocation (which involves the ball and socket joint). AC separations are caused from falls directly onto the shoulder. There are three main ligaments that can be stretched or torn. The injury is graded based upon the number of ligaments injured and the amount of separation between the clavicle and the scapula.

Symptoms

• Pain and swelling over the AC joint after a fall.
• Higher-grade injuries are characterized by increased deformity.
• Popping and weakness of the arm are common initially after the injury.
• Occasionally can be associated with other injuries, including rotator cuff tears, labral tears, and injury to the nerves or vessels. 

Diagnosis

A physical examination can initially evaluate for pain and deformity to confirm the injury. An x-ray is necessary to establish the severity of the injury. A MRI may be necessary to evaluate for associated injuries to the soft tissue.

Prevention   

People who participate in high-risk for falling sports may consider protective equipment and education in falling techniques to avoid landing on their shoulder.