• VSON

Acromioclavicular Joint (AC joint) Injuries & How We Fix Them

Acromioclavicular Joint (AC joint) injuries are among the most common year-round shoulder injuries we see at Vail-Summit Orthopaedics & Neurosurgery. Let’s start by answering three questions: What exactly is the AC joint? What activities lead to injury of the AC joint? How do we treat AC joint injuries?

Your AC joint is the connection between your clavicle (or collarbone), and your scapula, (or your shoulder blade). This important stabilizer is the boney connection between your scapula and your chest wall. As you follow your clavicle from the top of your sternum out toward your arm, you will feel a bump at the top, right above your shoulder. That is your AC joint.


AC joint separation or dislocation is a common upper extremity injury that occurs when someone falls directly onto the top of their shoulder. During this injury, the arm, and its attached scapula are forced downward, while the clavicle remains in place. This occurrence ruptures the ligaments between the scapula and the clavicle. The severity of the injury determines the number of these ligaments that are ruptured and determines our treatment.


Activities that yield the highest rates of AC joint injuries:

  • Skiing and snowboarding

  • Biking

  • Contact sports such as hockey, rugby and football

Signs and symptoms of AC injury:

  • Pain when lifting objects

  • Pain with overhead movement

  • Bruising and swelling on the shoulder

  • Tenderness

  • “Popping” of the shoulder blade