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AC Joint Separation Treatment

Apr 15, 2010 | By Gregory Waryasz

The acromioclavicular (AC) joint is the joint where the clavicle articulates with the scapula at the acromion. The term AC joint separation refers to ligamentous injuries to the acromioclavicular or coracoclavicular ligments, resulting in displacement of the clavicle. A physician will typically perform a physical examination of the shoulder and order imaging studies.

Classification of AC Joint Separations

The Rockwood Classification system is commonly used to grade the injury to the AC joint. A type I injury occurs when there is no disruption of the AC ligament or coracoclavicular ligament. A type II injury involves a disruption of the AC ligament, while the coracoclavicular ligament remains intact. A type III injury involves both disruption of the AC and the coracoclavicular ligaments. A type IV injury involves a type III injury pattern along with displacement of the distal clavicle into/through the trapezius muscle posteriorly. A type V injury to the AC joint is a type III injury with the addition of a disruption of muscular components. This results in a severe gap between the acromion and the clavicle. A type VI injury is a type III injury with an additional inferior dislocation of the distal clavicle to a point inferior to the coracoid process and posterior to the biceps and coracobrachialis tendon.

Nonsurgical Treatments

Treatment of type I, II and most type III AC joint injuries is nonoperative. Using a simple shoulder sling for comfort helps relieve the tension on the AC joint and allows for healing to occur. Treatment may leave the patient with a mild deformity, but, generally, patients regain full function in less than six weeks. Typically, symptoms improve significantly in two to four weeks.

Nonsurgical Treatment Complications

In AC joint injuries treated without surgery, the most common treatment complications are arthritis and instability. Arthritis can occur years after the initial injury. While instability is uncommon in type I or type II injuries, if a type II injury does not heal properly, the AC joint can have anterior/posterior instability or be subject to subluxation (incomplete/partial dislocation).

Surgical Treatments

Surgery is indicated for some type III and all type IV, V and VI separations. Open reduction of the AC joint can occur in conjunction with distal clavicle resection or fascial repair. The surgical procedure varies based on the specific injury type. Primary coracoclavicular fixation can be completed with placement of a screw between the clavicle and coracoid process. This essentially mimics the AC ligament. Suture fixation of the clavicle to the coracoid is also an option. This also mimics the AC ligament. A coracoclavicular ligament reconstruction can be performed using a free tendon graft or through a transfer of the AC ligament (Modified Weaver-Dunn transfer). In March 2008, in an article in the "Clinical Orthopaedics and Related Research" journal, D. Tomlinson, M.D., et al, describe an arthroscopically assisted AC joint repair for high-grade injuries that require a reconstruction of the coracoclavicular ligament.
Other treatments have higher complication and failure rates, including primary AC joint fixation, dynamic muscle transfers of the biceps and clavicle hook plate placement.
After surgical repair, the patient is placed in a sling for approximately six weeks for immobilization. Strength and range of motion exercises are then initiated. Full recovery can be seen approximately six months after surgery.

Surgical Treatment Complications

General surgical treatment complications include wound infection, bleeding and need for further surgeries. There can be failure of fixation, resulting in a return to a state of deformity. Repair instruments, such as sutures, screws and plates, can migrate and fracture under stress.

References

Article reviewed by Dana Montey Last updated on: Apr 15, 2010

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