Shoulder Separations
also known as AC Separations

Normal AC jointThe AC joint is located at the tip of the shoulder where the shoulder blade (scapula) and collarbone (clavicle) come together at a point on the upper part of the shoulder blade called the acromion.  These two bones are held together by ligaments.  One group of ligaments envelope the joint to form a capsule that covers the joint; these ligaments are termed the acromioclavicular ligaments.  Another set of ligaments stabilize the shoulder by holding the clavicle in place by attaching it to a bony projection on the surface of the shoulder blade called the coracoid process.  These ligaments are called the coracoclavicular ligaments.  There is a disk of cartilage in the joint between the two bones that help guide the joint movement.  As you move your shoulder, the AC joint allows the movement to occur between the clavicle and scapula.

What is an Acromioclavicular joint separation of the shoulder?

AC joint separations, also known as shoulder separations, are a type of shoulder traumatic injury caused by a direct impact fall onto the top or side of the shoulder.  It is a common injury seen in sports like football, soccer, hockey, mountain biking, road cycling, and skateboarding.  The injury is seen in fall from heights such as from ladders or scaffolding.

Types of Shoulder Separations

Shoulder separations are graded 1 through 5.  Treatment is based on the grade of shoulder separation injury suffered by the individual.

Grade 1 Separation:

Grade 1 AC separations are sprains of the Acromioclavicular joint.  The AC joint remains aligned and stable.  Symptoms include mild swelling and pain over the AC joint.  Patients experience tenderness to touch over the AC joint. There is often pain with overhead and cross-chest motions of the shoulder.

Grade 1 separations tend to resolve with rest, ice, and nonsteroidal anti-inflammatory medications.  Slings may be used for support until the pain goes away.

Recovery takes anywhere from 2 to 6 weeks to full resolution.  Activity is allowed to resume as discomfort allows.

Grade 2 Separation:

Grade 2 AC separations are more severe sprains of the Acromioclavicular and Coracoclavicular joint.  The AC joint remains well aligned and stable though there is usually a visible bump present after injury.  Symptoms include moderate swelling and pain over the AC joint.  There may be a slight sense of laxity in the joint with pressure.  Patients experience tenderness to touch over the AC joint.  There is pain at rest and with overhead and cross-chest motions of the shoulder.

Grade 2 separations tend to resolve with rest, ice, nonsteroidal anti-inflammatory medications.  Slings provide support for the AC joint and is used until the pain resolves.

Recovery takes anywhere from 6-8 weeks to full resolution.  Activity is allowed to resume as discomfort allows.

Grade 3 Separations:

Grade 3 AC separations involve a true dislocation of the AC joint.  There is complete separation between the acromion and clavicle resulting in a grossly visible deformity of the AC joint.  The collar bone appears to be elevated in comparison to the acromion.  In actuality, the shoulder blade is drooping in relation to the clavicle.  There is complete disruption of the acromioclavicular and coracoclavicular ligaments as well as the acromioclavicular joint capsule.  Symptoms include gross deformity of the joint, pain with motion of the shoulder, and decreased overhead and cross-chest motion ability.

Grade 3 separations result in a permanent deformity when left untreated surgically.  Nonetheless, conservative treatment is a viable option for a “stable” grade 3 separation.

Surgical intervention can be performed acutely with stabilization and/or reconstruction of the coracoclavicular ligaments.  In some instances, both stabilization and ligament reconstruction are performed to re-create long term stability for the AC joint.

Recovery from conservative treatment follows the pathway of grade 2 separations.  Generally, it can take 8-12 weeks to resume all activities without pain.

Surgical recovery, whether stabilization or reconstruction, can take 3-4 months for full recovery to unrestricted use.  Surgical recovery has good to excellent results for restoration of alignment, long term stability, and pain relief.

Grade 4,5,6

These high-grade AC separations are the result of high energy trauma such as falls from a significant height or a motor vehicle accident.  These severe injuries require surgical intervention.


The diagnosis of AC separations can be made through the patient’s history and physical examination.  X-rays of the shoulder are generally performed to rule out fractures of the clavicle, shoulder, and coracoid.  X-rays also help identify the grade of the AC separation injury.

Occasionally, MRI studies may be ordered if there is a concern for other associated soft tissue injuries.

Non-surgical treatment

The goal of treatment for an AC separation is to eliminate pain and restore movement to the shoulder.  For Grade 1 and 2 AC separations, treatment, initially, is conservative, consisting of rest and non-steroidal anti-inflammatory medications such as aspirin, ibuprofen, and naproxen.  Ice may be applied intermittently as needed to decrease the pain and inflammation at the joint.  Cortisone, an anti-inflammatory steroidal medication, may be injected into the joint if the pain persists after the administration of non-steroidal medications.  To avoid further aggravation of the condition, there should be a lessening of activities that tend to put undue stress on the AC joint until the pain has subsided.

Grade 3 AC separations can be treated either conservatively or surgically.  The factors that determine which pathway of treatment to pursue is based upon several factors including:

  • Patient goals and expectations
  • Requirements and/or demands regarding use of the affected shoulder
  • Risk of re-injury based upon work, sports, or other recreational activities
  • How the injury may affect the patient’s use of the shoulder to pursue their activities in life.

For grade 3 separations, the patient and the surgeon will discuss the best options based upon these and other considerations.

Surgical treatment

Should rest, ice, medication, and modifying activities not work to reduce the pain and swelling, surgery may be the next step in treatment for grade 3 separations.  Surgical treatment for grade 3 AC separations is usually a combination of stabilization of the joint with an internal brace with a reconstruction of the coracoclavicular ligaments.  There are several orthopedic implant devices suitable to stabilize the AC joint.  The coracoclavicular ligament reconstruction is often performed using a cadaveric tendon graft.

Surgery is performed as an outpatient procedure.  Post-surgical recovery is a slow process during which the AC joint is protected for several weeks.  Patients wear their sling to support and unload the AC joint from stress and gravity for a minimum of 6 weeks after surgery.  Use is restricted as is the allowable weight to the surgically operated arm.  Physical therapy is initiated at 4-6 weeks after surgery to promote shoulder range of motion.  Full recovery can take 3-4 months such that full use is allowed with the operated extremity.

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