Acromioclavicular Separations

Mandeep Singh Virk, MD, MBBS

Mark P. Cote, PT, DPT, MSCTR

Augustus D. Mazzocca, MS, MD

Dr. Mazzocca or an immediate family member serves as a paid consultant to Arthrex, and has received research or institutional support from Arthrex. Dr. Virk or an immediate family member serves as a board member, owner, officer, or committee member of the American Journal of Orthopedics and Techniques in Orthopaedics. Neither Dr. Cote nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article.

Introduction

Acromioclavicular (AC) joint separations commonly occur in contact sports (rugby, wrestling, ice hockey, and football). The usual mechanism of injury involves a fall with direct trauma to the posterosuperior part of the shoulder. Less commonly, injury occurs by an indirect mechanism, with a fall on an outstretched adducted arm or elbow driving the humeral head into the AC joint. AC joint separations involve varying degrees of injury to the AC ligaments, coracoclavicular ligaments, and deltotrapezial fascia. They are classified according to the severity of injury, radiographic findings, and position of the clavicle relative to the acromion (Table 3.1). Higher-grade separation results in AC joint instability, and can lead to shoulder girdle dysfunction. Less severe types I and II as well as many type III injuries are routinely treated nonoperatively (Figure 3.1).

Surgical treatment is pursued for more severe acute injuries, types IV to VI and selected type III injuries, as well as symptomatic chronic AC separations. Numerous surgical procedures, open and arthroscopic, have been described, but the ideal surgical procedure is not known. Reconstruction of the AC joint and the coracoclavicular (CC) space requires a thorough understanding of the relevant anatomy, biomechanics, and stabilizers of the AC joint. The AC and CC ligaments are primary stabilizers of the AC joint; the deltoid and trapezius muscles and fascia are the secondary dynamic stabilizers. The AC joint capsular ligaments, specifically the superior and posterior AC capsular ligaments, are the primary restraints to anterior-to-posterior translation and confer horizontal stability. The CC ligaments (trapezoid and conoid) contribute to the vertical stability. The trapezoid ligament attaches on the undersurface of the clavicle at an anterolateral position. The conoid is a broad, stout ligament located in a posterior and medial position (conoid tubercle) relative to the trapezoid ligament (Figure 3.2). Both the trapezoid and conoid ligaments are attached distally to the base of the coracoid posterior to the pectoralis minor insertion on the coracoid. Anatomical Coracoclavicular Ligament Reconstruction (ACCR) attempts to restore stability to the AC joint and shoulder girdle.

Postoperative rehabilitation plays a critical role in the success of surgical management both by protecting the repair to ensure appropriate healing and by leading a patient through a progressive program of exercise that results in anatomic restoration and functional recovery. Early on, postoperative immobilization is an integral part of the rehabilitation to protect the construct during the initial phases of healing. During this period of immobilization, restoring scapular control and shoulder range of motion (ROM) through gradual low-load exercises allows an effective transition into the strengthening phase of rehabilitation. During the strengthening phase, it is important to appreciate that patient-specific goals are met prior to advancing the intensity of the strengthening program. Thus, a guided postoperative rehabilitation program plays a critical role in the surgical management. In this chapter, we describe the indications and surgical techniques for treatment of AC joint separations, and detail the postoperative rehabilitation.

Surgical Treatment

The main goals of surgical treatment of AC joint separations are to achieve a pain-free shoulder with full ROM and strength. Treatment of acute type III AC separations is controversial and a matter of ongoing debate. Although many patients can be treated without surgery, there are cases such as higher-demand athletes and laborers who may benefit from acute repair. Higher-grade AC joint separations (types IV, V, and VI) are best managed surgically.

Multiple operative procedures have been described for treating AC joint separation, but there is a lack of consensus regarding the ideal procedure. These procedures can be broadly categorized into the following:

Acromioclavicular joint stabilization, using hook plates, pins, or Kirschner wires (K-wires)
Coracoclavicular space stabilization, using suture loop, screw, endobutton, suture anchor
Ligament reconstruction: CC ligament and/or AC ligament reconstruction with autograft or allograft and CC augmentation
Dynamic muscle transfer: Proximally based conjoint tendon transfer

Open ACCR is our surgical procedure of choice for the treatment of complete AC joint separation. The postoperative rehabilitation described here is specific for the ACCR procedure, but can be modified to be adapted to other methods of surgical reconstruction of the AC joint.

Figure 3.1 Radiograph of bilateral Zanca view demonstrating increased coracoclavicular distance (red arrow) and complete acromioclavicular joint separation (blue arrow) on the left.

Figure 3.2 Illustration of the anatomy of the coracoclavicular ligaments and acromioclavicular ligaments. The conoid is a broad, stout ligament that fans out from the base of the coracoid and attaches to the conoid tubercle on the undersurface of the coracoid. The trapezoid ligament is a more anterolateral structure compared to the conoid ligament. (Reproduced with permission from Detton AJ: Grant’s Dissector, ed 16. Philadelphia, PA, Wolters Kluwer Health, 2016.)

Table 3.1 ROCKWOOD CLASSIFICATION FOR ACROMIOCLAVICULAR INJURIES

Type	AC Ligaments	CC Ligaments	Deltopectoral Fascia	Radiographic CC Distance Increase	Radiographic AC Appearance	AC Joint Reducible
I	Sprained	Intact	Intact	Normal (1.1–1.3 cm)	Normal	N/A
II	Disrupted	Sprained	Intact	<25%	Widened	Yes
III	Disrupted	Disrupted	Disrupted	25%–100%	Widened	Yes
IV	Disrupted	Disrupted	Disrupted	Increased	Posterior clavicle displacement	No
V	Disrupted	Disrupted	Disrupted	100%–300%	N/A	No
VI	Disrupted	Intact	Disrupted	Decreased	N/A	No
AC = acromioclavicular, CC = coracoclavicular.

Contraindications

Types I and II AC joint separations

Anatomic Coracoclavicular Ligament Reconstruction

In ACCR (Figure 3.3, A–K), the conoid and trapezoid ligaments are reconstructed using autograft or allograft tendon tissue. The capsular ligaments of the AC joint are also reinforced posteriorly and superiorly with the same graft tissue. The fixation of the graft on the clavicle is performed using interference screws through the drill holes. The fixation of the graft on the coracoid can be performed by looping the graft around the coracoid base (loop technique, our preferred method) or by using
an interference screw (tenodesis technique) in the coracoid. We incorporate a collagen-coated, braided, nonabsorbable suture along with the graft in our reconstruction. We believe that the graft provides the biologic form of fixation, while the collagen-coated suture provides the nonbiologic form of fixation.

Figure 3.3 Clinical photographs of open anatomic coracoclavicular ligament reconstruction (ACCR). A, The saber skin incision is approximately an inch medial to the acromioclavicular joint. B, Full-thickness skin flaps are created to expose the deltotrapezial fascia. C, Periosteomuscular flaps are elevated to skeletonize the distal end of clavicle. D, The allograft (peroneus longus) is prepared and tendon ends are bulleted for easy passage through tunnels. E, The conoid (medial) and trapezoid tunnels (lateral) are created using a 5-mm reamer. F, The autograft or allograft tissue is looped around the coracoid along with a collagen-coated FiberWire. G, The graft and collagen coated FiberWire is passed through both the tunnels in the clavicle and reduction of the acromioclavicular joint is performed by passively shrugging the shoulder. H, A large pointed reduction forceps with its tines on the coracoid and clavicle is used to further achieve and maintain reduction till final reconstruction is achieved and is held by a pointed reduction forceps. I, The conoid ligament is anchored into the tunnel using a 5.5 PEEK interference screw followed by securing the trapezoid ligament with a 5.5 PEEK interference screw. The collagen-coated FiberWire is then tied to itself to give nonbiologic support. J, Excess graft is used to reconstruct or reinforce the acromioclavicular ligaments. K, After the final ligament reconstruction is performed, the deltotrapezial fascia is then closed in layer and is an important component of ACCR.

The patient is placed in the beachchair close to the edge of the table with a small bump under the medial scapular edge to stabilize it and elevate the coracoid anteriorly. The arm is draped free so that maneuvers to reduce the AC joint can be performed. Prior to prepping and draping of the surgical field, fluoroscopy is used to ensure that appropriate imaging can be obtained during surgery.

A skin incision is centered approximately 1 inch medial to the AC joint starting at the posterior clavicle directed toward the
coracoid process along Langer’s lines (Figure 3.3, A). The deltotrapezial fascia is defined in the depth of the incision (Figure 3.3, B) and full-thickness fascio-periosteal flaps are elevated from the midline of the clavicle both posteriorly and anteriorly to expose the lateral end of the clavicle and AC joint (Figure 3.3, C).

An allograft (peroneus longus) or autograft (semitendinosus) tendon can be used for this procedure. The tendon is sized using a standard tendon sizer (usually 5 mm) and tendon ends are bulleted for easy passage through bone tunnels. A whipstitch or grasping suture is placed in the two free ends of the tendon for passage through the bone tunnels (Figure 3.3, D).

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