There is a consensus that lower grade injuries, type I and II, can be treated nonoperatively with low incidence of chronic pain or disability. Likewise, the significantly displaced injures to the AC joint complex with complete disruption of AC joint and CC ligamentous complex and involving greater than 300% displacement of the clavicle, threatened skin, or an irreducible AC joint warrant surgical treatment. In these situations, this technique can be applied acutely. Controversy still remains regarding the treatment of type III injuries. To further complicate the issue, the best clinical method of determining a type III from a type V injury has not been elucidated. From a clinical perspective, the ability to reduce the scapula to the clavicle has been described as an indication of injury gradation. The assumption is if the deltotrapezial fascia is still intact then reduction is usually possible. Therefore, reducibility correlates with intact overlying fascia and type III injury (12, 13). Conversely, inability to reduce the joint may be caused by “buttonholing” of the clavicle through a ruptured fascial layer. The “Shrug test” is described as an attempt at providing a radiographic distinction between these two injuries, as exemplified by its use in a type III and type V injury (Figs. 18-1 and 18-2). Using the Zanca view, radiographs are taken during an active shoulder shrug. AC joint congruity, reduction, and CC distance are measured to a radiograph obtained pre- and postshrug. In our current experience, clinical reduction does not correlate with radiographic AC joint reduction, and this finding has not been helpful in planning clinical treatment.

An important consideration in the preoperative planning is the radiographic assessment of the injured and uninjured AC joint complex. We commonly obtain bilateral standing Zanca view films (x-ray beam 10 to 15 degrees caudad to cephalad, using one-half of the standard penetrance) to directly measure CC distance side to side. This is performed with the patient standing, arms at the side without any weights or support.
Additionally, an axillary lateral radiograph is taken to determine the sagittal position of the distal clavicle. Stryker notch radiographs can be taken to rule out a coracoid fracture, and, if present, CC ligament reconstruction is contraindicated. A coracoid fracture is most commonly seen when there is superior displacement of the clavicle with minimal change in the CC distance from the uninjured side.

Prior to surgical reconstruction, it is important to determine if any glenohumeral pathology coexists. SLAP lesions and biceps tendon injuries must be ruled out as they can also be found in the same patient populations following similar injuries, and pain originating from the superior anterior shoulder can be difficult to localize. The innervation of the AC joint and glenohumeral joint is from the lateral pectoral and suprascapular nerves. In a study by Gerber in 1998, it was suggested that irritation to the AC joint produced pain over the AC joint, in the anterolateral neck and in the region in the anterolateral deltoid. Glenohumeral or subacromial space produced
pain in the region of the lateral acromion and the lateral deltoid muscle but did not produce pain in the neck or trapezius region, so clearly directed questioning about pain localization may differentiate. A careful history and evaluation of the mechanism of injury are also critical. Provocative maneuvers, like cross-arm adduction, lidocaine injections, and direct palpation, are important differentiation tools (4).

At the University of Connecticut, all acute type I, II, III, and V injuries are managed with a 6-week course of supervised rehabilitation to maximize rotator cuff strength and the stabilizing function of the periscapular muscles (14). Altered shoulder biomechanics leading to symptoms can be the sequelae of complete AC joint displacement. A recent study estimated that 70% of patients with type III injuries had scapular dyskinesis and, eventually, SICK scapula syndrome (Scapular malposition, Inferior medial border prominence, Coracoid pain and malposition, and dyskinesis of scapular movement) developed in 54% of patients with chronic type III AC dislocations (15, 16). If pain or disability persists following rehabilitation and conservative treatment, surgical reconstruction is discussed. However, the open ACCR surgical technique could be applied to the treatment of acute significantly displaced injuries in the young active patient if conservative treatment is not appropriate given displacement or instability.