AC Joint Separation
Written by: Dr. Popovitz.
Board-Certified Orthopedic Surgeon | Fellowship-Trained Sports Medicine, NYU Langone Medical Center | FAAOS
Co-Founder, NY Bone & Joint Specialists | Lenox Hill Hospital - Northwell Health
Recognized: New York Magazine Best Doctor | New York Times Super Doctor | IAOS Leading Physician of the World | IAOS Top Orthopedic Surgeon in New York
Date Published: July 24, 2018
Last Updated: November 8, 2018
Last Medically Reviewed: November 8, 2018
This page has been written and reviewed by a fellowship-trained, board-certified orthopedic surgeon with over 20 years of clinical experience. All clinical claims are supported by peer-reviewed literature and current AAOS and AOSSM guidelines. See References section below.
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Surgery performed at Lenox Hill Hospital - Northwell Health
WHAT IS THE AC JOINT?
The acromioclavicular joint is a cartilaginous junction between the collarbone and the acromion, a bony extension of the shoulder blade. Responsible for overhead motions, it’s one of four joints that comprise the shoulder.
WHAT CAUSES AC JOINT PAIN AND INJURY?
Pain in the AC joint can be caused by a traumatic injury such as a direct fall onto the shoulder or a blow to the top of the shoulder blade. As a result, it’s a common injury in contact sports such as football, hockey, and rugby.
AC JOINT SEPARATION SYMPTOMS
Common symptoms of an AC joint separation include:
- Moderate to severe pain and swelling at the top of the shoulder when sleeping or moving the arm overhead
- A general sense of weakness or instability in the affected shoulder
- Restricted range of motion
- popping sound while moving the joint
Patients will likely notice a protrusion from the top of the shoulder, as well, and the shoulder will seem to hang lower than it normally does.
AC JOINT SEPARATION GRADING
AC joint separations are classified by severity. Higher grades reflect greater damage to the joint, while lower grades reflect less damage.
Grade 1 AC Joint Separation
A grade 1 separation refers to mild damage to the ligaments and no damage to the bones. It is the most common type.
Grade 2 AC Joint Separation
A grade 2 separation refers to a rupture of the AC ligament. The coracoclavicular ligament may also sustain some damage.
Grade 3 AC Joint Separation
A grade 3 separation refers to a rupture of the AC and coracoclavicular ligaments. Grade 4, 5, and 6 separations are more severe variations.
AC JOINT SEPARATION TREATMENT & RECOVERY TIME

The good news if you’ve suffered an AC joint separation: injuries of this kind generally respond favorably to conservative treatment, with most patients completely recovering without surgery in six to twelve weeks. A typical rehabilitation plan entails some combination of rest, icing, anti-inflammatory medications, and physical therapy. Bracing the separated joint in place or setting the shoulder in a sling may diminish pain and any feeling of instability in the clavicle bone.

While most AC separations don’t require surgery, more severe cases may need to be repaired with a short arthroscopic procedure. During this procedure, the surgeon replaces any torn ligaments with tissue taken from the patient or a donor and stitches it to the joint. In some cases, the surgeon may completely reconstruct the joint with ligaments sourced from elsewhere in the shoulder. In any case, you will be able to return to your day-to-day activities relatively quickly, but most patients require four to six months of physical therapy before returning to more rigorous physical activities.
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EXPERIENCING PAIN? DO YOU HAVE AN INJURY?
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