What is an AC joint injury?
The acromioclavicular (AC) joint is where your collarbone meets the acromion, the bony tip of the shoulder blade. Two sets of ligaments keep it aligned. In a fall onto the point of the shoulder, those ligaments can stretch or tear, and the collarbone rides up relative to the shoulder blade. That creates a visible bump and is commonly called a separated shoulder. It is different from a dislocated shoulder, which involves the ball and socket.
Injuries are graded from I to VI. Grades I and II are sprains, grade III is a complete tear of the ligaments, and grades IV to VI involve more displacement or direction changes and are less common.
What does it feel like?
The top of the shoulder is painful, swollen and tender, and the arm is sore to lift across the body or overhead. A grade III injury shows a bump or step at the top of the shoulder. Pain usually settles over a few weeks in lower grades.
Do I need surgery?
For most AC joint separations, no. Treatment is usually a sling for comfort, early gentle motion, and then strengthening. The bump usually remains.
Surgery is considered for high-grade injuries (IV through VI), for laborers or overhead athletes with a complete separation who remain symptomatic, and for those whose symptoms persist after therapy.
What about AC arthritis?
The AC joint is a common site of wear-and-tear arthritis, especially in weightlifters and in people with prior injury. Typical symptoms are pain on top of the shoulder, pain reaching across the body, and tenderness right over the joint. It can be treated with activity changes, therapy and cortisone injections. If those fail, arthroscopic removal of the end of the collarbone (distal clavicle excision) relieves the pain. It is often done together with other shoulder procedures.
What are the surgical options?
For acute or chronic high-grade separations, the ligaments are reconstructed, usually with a tendon graft and a suture-button device that holds the collarbone in place while the graft heals. Dr. Stepanyan will explain which technique fits your injury, and how soon it should be done. Reconstruction is more successful when done within a few weeks of injury than in long-standing cases.
Should I get a second opinion?
If you have been told surgery is the only choice for a separated shoulder, or you have had pain on top of the shoulder for months, a second opinion helps. Request a visit and bring your X-rays.
Where can I see Dr. Stepanyan?
Dr. Stepanyan sees shoulder patients in Glendale, East LA and Santa Fe Springs.
What does recovery look like?
These are typical stages for a separated shoulder treated without surgery, and after a reconstruction. Your own plan may differ.
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Weeks 0–2
Settle the pain
A sling helps comfort. You begin gentle pendulum swings and elbow, wrist and hand motion. Ice and pain medicine help.
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Weeks 2–6
Restore motion
Without surgery, motion returns as pain allows. After reconstruction, the sling continues for about six weeks and motion is limited.
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Weeks 6–12
Build strength
Strengthening starts for the shoulder blade and rotator cuff muscles. Most people are back to daily activities.
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Months 3–6
Return to activity
Lifting and contact sport are resumed gradually. After reconstruction, contact sport usually waits until about six months.
A bump on the top of the shoulder is common after a grade III injury even when the shoulder works well.