AC Separation Frequently Asked Questions

The shoulder is the most mobile joint in the human body with a complex arrangement of bone and
soft tissue (ligaments, tendons, and muscles) that work together to produce shoulder movement.
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An acromioclavicular joint separation, or AC separation, is a very frequent injury among
physically active people. In this injury the clavicle (collar bone) separates from the scapula (shoulder
blade). It is commonly caused by a fall directly on the “point” of the shoulder or a direct blow received
in a contact sport. Click here for more information..

Grade 1 A slight displacement of the joint. The acromioclavicular ligament may be stretched or
partially torn.
Grade 2 A partial dislocation of the joint in which there may be some displacement that may not be
obvious during a physical examination.
Grade 3 A complete separation of the joint. The acromioclavicular ligament, the coracoclavicular
ligaments, and the capsule surrounding the joint are torn.
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Grade 1 Tenderness and bruising around the joint, minor pain with movement.
Grade 2 Moderate to severe pain at the joint, swelling, pain with movement, may be a small bump on
top of shoulder, clavicle may move when pushed.
Grade 3 Typically the injured person supports the elbow immediately to lessen pain caused by
movement, swelling, popping may occur when joint is moved, shoulder deformity and bump on top of
shoulder, and AC joint is very unstable.
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A diagnosis of acromioclavicular separation is made after a physician will take the patient’s history
and perform a physical examination. A diagnostic anesthetic injection and X-rays of the shoulder can
confirm a diagnosis. Click here for more information..

Most grades of AC separation can be treated without surgery with most patients recovering within two
to three months. Non-operative treatment includes rest, ice, anti-inflammatory medication, and a
rehabilitation program to restore normal motion and strength. Click here for more information..

The surgical technique most often performed involves the reconstruction of the coracoclavicular
ligaments and the excising (removal) of the distal (shoulder) end of the clavicle. Distal clavicle
resection without the repair of the ligaments may lead to excessive rotation of the scapula. Click here
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Complications of AC joint injuries are persistent instability of the shoulder girdle or residual pain with
activity. Failure of the acromioclavicular ligament and coracoclavicular ligaments to heal can lead to
pain and a sense of instability with overhead activity. If the end of the clavicle remains unstable
because of lack of scarring, contact sports or overhead tasks may be painful. Other complications are
related to hardware failure. The screws used to fix these two bones together can pull out if the patient
does not wear a sling after surgery as instructed. Click here for more information..

Patients with lower energy AC joint injuries that respond to conservative non-operative treatment can
recover in as little as one week for a Grade I injury to an average of twelve weeks for a Grade III
injury. Click here for more information..

No. In fact the vast majority of AC separations do very well with conservative treatment of the
symptoms. Most AC injuries are grade I, II, or III and these generally do not require surgery. Usually
the joint remains sore for two to six weeks and then full return to activity is the norm. Only unstable
grade III injuries and high-energy AC separations, which are often the result of motor vehicle
accidents, require surgery for full recovery. Click here for more information..

The clavicle will become stable in its newly elevated position, but without surgery the “bump” will
remain. The joint will function normally and will not remain tender to touch or movement. This minor
cosmetic deformity will persist but will not interfere with overhead activities or participation in sports.
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An AC resection is a procedure in which the end of the clavicle is removed and the acromioclavicular
ligament in reattached into the end of the clavicle to replace the ligament torn during injury. Once the
initial injury has healed and the clavicle has regained stability from scar tissue there is no functional
loss with an AC resection. In the rare instance that the AC joint remains painful after a separation, but
does not require stabilization, an AC resection is very effective in relieving pain without sacrificing
function. If, however, the clavicle is unstable at the time of resection, a full reconstruction of the
coracoclavicular ligaments is necessary to maintain the stability of the upper extremity. Click here for
more information.

Absolutely. Most athletes in contact sports have had a low energy AC separation at some time in their
careers. Except for the slight deformity that remains, there is no clinical significance to a healed AC
separation. Occasionally high-energy AC separations that have disruption of the AC and CC
ligaments will require surgery, but these injuries are usually apparent early on with a correct X-ray
evaluation. Grade I, II, and most grade III AC separations will heal without treatment and a full return
to sports can be expected.