AC Joint Injuries
What is the acromioclavicular (AC) joint?
The AC joint is where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion). It helps support shoulder motion and stability, especially during lifting and overhead activities.
An AC joint injury — also called a shoulder separation — occurs when the ligaments that hold the clavicle and acromion together are stretched or torn. Injuries range from mild sprains to complete dislocations of the joint.
Symptoms include pain at the top of the shoulder, swelling, bruising, and a visible bump where the clavicle may protrude. The pain often worsens with lifting, reaching, or pressure on the shoulder.
AC joint injuries commonly result from a fall directly onto the shoulder, such as during contact sports, biking accidents, or slipping on ice. The impact forces stress the joint and ligaments.
Diagnosis includes a physical exam to assess tenderness, joint stability, and deformity. X-rays are used to grade the injury and check the position of the clavicle. In some cases, MRI may be used to evaluate ligament damage and to check for other injuries.
Most mild to moderate AC joint injuries (Grades I–III) are treated without surgery. Treatment includes rest, icing, a sling, and physical therapy. Surgery may be considered for higher-grade injuries (Grades IV–VI), especially in active individuals or those with persistent pain or instability.
AC joint reconstruction is a surgical procedure that restores the alignment and stability of the joint. This often involves using a graft and/or strong sutures to reconnect and reinforce the torn ligaments between the clavicle and coracoid process.
Recovery typically takes 4 to 6 months. Patients use a sling for a few weeks, followed by gradual physical therapy. Most return to daily activities within 3 months and to sports around 4 to 6 months, depending on healing and strength.
At a Glance
Sachin Allahabadi, MD
- Board-Certified & Fellowship-Trained Sports Medicine Surgeon
- Expertise in Minimally Invasive Knee & Shoulder Surgeries
- Assistant Professor of Clinical Orthopaedic Surgery, Houston Methodist Hospital & Weill Cornell Medical College
- Learn more
