Surgical Treatment

Abstract

Acromioclavicular joint injuries that require surgery may be managed using arthroscopic and open techniques. This chapter reviews the indications, techniques, complications and post-operative rehabilitation of arthroscopic surgical treatment.

Keywords: Acromioclavicular joint, AC joint arthroscopy, AC joint, AC joint reconstruction, Shoulder Separation

Introduction

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  Injuries to the acromioclavicular (AC) joint are common shoulder injuries with an incidence of 1.8/1000 per year ( ).

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  The majority of AC injuries occur in athletes from contact sports as a result of collision or direct fall onto the shoulder.

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  In general, concomitant lesions to the shoulder girdle may occur in up to approximately 20% of cases; shoulder arthroscopy during AC joint stabilization may help detect these lesions ( ).

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  Rockwood and colleagues developed the classification scheme for AC joint injuries, recognizing the importance of the coracoclavicular (CC) ligaments in joint stability ( ).

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  Surgery is the treatment of choice for Rockwood injuries types IV through VI and for patients with persistent symptoms and AC joint instability after nonoperative treatment of lower grade AC joint injuries. Management of type III injuries is controversial, and types I and II are treated nonoperatively.

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  Our preferred surgical technique involves a knotless fixation system because it can reduce irritation of the subcutaneous tissue.

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  Following surgical treatment of AC joint injury, patients typically obtain good to excellent postoperative clinical outcomes; however, a complication rate of approximately 25% can negatively impact the outcomes ( ).

Classification

Rockwood and colleagues developed the most commonly used classification system for AC joint injuries ( Fig. 12A.1 ) on the basis of the work of . In Rockwood type I injuries, the AC ligaments are sprained but there is no anatomic dislocation, and the trapezius and deltoid fascia remain intact. Type II injuries involve rupture of the AC joint ligaments, with the CC ligaments and the trapezius and deltoid fascia remaining intact. With type III injuries, the AC and CC ligaments are both ruptured, and the clavicle is superiorly displaced by 25% to 100% in comparison with the uninjured side; the trapezius and deltoid fascia are not disrupted. Type IV injuries are similar to type III, but with horizontal instability of the distal end of the clavicle and disruption of the trapezius and deltoid fascia. Type V injuries are again similar to type III, but the clavicle is superiorly displaced more than 100% in comparison with the uninjured side with disruption of the trapezius and deltoid fascia. Finally, type VI injuries, are rarely seen and involve rupture of both AC and CC ligaments with inferior displacement of the distal clavicle; the trapezius and deltoid fascia are disrupted ( ). proposed a modification to the classic Rockwood classification in which type III injuries may be further subdivided into IIIA and IIIB; type IIIA injuries are stable and may respond well to conservative management, but type IIIB injuries are unstable and should be treated surgically.

Patient Examination and Diagnostics

AC joint injuries are rarely subtle and can often be diagnosed by inspection and palpation. Patients typically present holding the injured extremity at the elbow with the contralateral arm for pain relief. The AC joint is tender to palpation, and range of movement (ROM) is limited owing to pain. Imaging evaluation ( Fig. 12A.2 ) should include standard axillary views, Y-views, and panoramic views. Although the axillary view can assist in determining posterior displacement (as in type IV injuries), the Y-view helps to detect further bony lesions of the shoulder. Panoramic views are useful to compare the injured AC joint with the uninjured side. Additional weighted stress views are often advocated to distinguish between types II and III; however, we do not routinely recommend this practice because it rarely alters treatment and causes unnecessary patient discomfort.

Surgical Treatment

Operative Technique

See Video 12A.1 .

• Video 12A.1 Operative technique demonstrating coracoclavicular ligament fixation for the treatment of acromioclavicular joint injuries.

  (From Tahal DS, Katthagen JC, Millett PJ. arthroscopic acromioclavicular joint reconstruction using knotless coracoclavicular fixation and soft-tissue anatomic coracoclavicular ligament reconstruction. Arthrosc Techn. 6(1);2017:e37-42.)

Diagnostic Arthroscopy and Coracoid Preparation

Diagnostic shoulder arthroscopy is performed with a 30-degree arthroscope through a standard posterior portal. With spinal needle localization, an anterior portal is created lateral to the coracoid process, followed by insertion of a 5-mm cannula (Arthrex, Naples, FL) and an intraarticular diagnostic arthroscopy is performed. Next, a mechanical shaver and radiofrequency ablator are used to expose the inferior surface of the coracoid process as well as to address any intraarticular pathology. If necessary, a 70-degree arthroscope may be utilized to assist with visualization of the subcoracoid space.

Knotless Coracoclavicular Fixation

After sufficient exposure of the coracoid, an additional anteroinferolateral (AIL) portal is created inferior and lateral to the previously placed anterior portal. An 8.25-mm cannula (Arthrex) is then inserted through the portal, and attention is turned to the superior aspect of the lateral clavicle. A 2- to 3-cm incision is created over the distal end of the clavicle perpendicular to its long axis, approximately 3 cm medial to the AC joint. The skin and subcutaneous tissues are sharply dissected to expose the superior surface of the clavicle.

An acromioclavicular aiming guide (Arthrex) is then placed through the cannula and positioned on the inferior aspect of the coracoid, centered medial to lateral. The drilling sleeve of the guide is placed on the superior aspect of the clavicle, centered anterior to posterior. A 3.0-mm cannulated drill (Arthrex) is then drilled from the superior aspect of the clavicle to the inferior aspect of the coracoid process under direct arthroscopic visualization. Great care must be taken at this point to ensure that the cannulated drill enters in the superocentral portion of the clavicle and that it exits at the posteroinferior aspect of the coracoid; if it is drilled incorrectly, the patient has a higher chance of postoperative clavicular or coracoid fracture. Next, a 5.0-mm unicortical reamer (Arthrex) is used to create a small socket in the superior aspect of the clavicle; this socket ultimately allows the superior clavicle fixation device to sit flush within the bone, thus minimizing soft tissue irritation for the patient.

The central pin of the drill is removed, and a shuttling suture is passed through the drill cannula from the superior aspect of the clavicle and out the inferior aspect of the coracoid, and retrieved through the AIL portal. The cannula is removed and the shuttling suture is used to pass the double-loaded knotless CC fixation device (Knotless AC TightRope, Arthrex) from superior to inferior and out the AIL portal. A large cortical fixation button (DogBone, Arthrex) is secured to the fixation device; it is then passed through the AIL portal while the knotless fixation device is tightened superiorly until the button sits flush on the inferior coracoid process. The knotless fixation is further tightened until the clavicle is reduced; intraoperative fluoroscopy is utilized at this point to confirm reduction. Also at this point, the suture ends may be cut or preserved for additional compression.

Allograft Coracoclavicular Ligament Reconstruction

Augmentation of the knotless CC fixation may be performed with an 8-mm double-diameter tibialis anterior or hamstring allograft. This is typically added in the patient who has a chronic acromioclavicular joint injury, in whom there is a lot of force on the reduction, or in whom there is considerable anteroposterior translation even after the CC ligaments have been reconstructed to reduce postoperative re-dislocations.

A switching stick is used to bluntly create two soft tissue tunnels from clavicle to coracoid. The first tunnel is created posterior to the clavicle and medial to the coracoid process under direct arthroscopic visualization; this recreates the anatomic orientation of the conoid ligament. A soft-tissue dilator (Arthrex) is placed over the switching stick, and the switching stick is removed. Subsequently, a rigid shuttling suture (Fiberstick, Arthrex) is passed through the dilator from superior to inferior and retrieved out the AIL portal. The process is repeated for the second tunnel, beginning anterior to the clavicle and exiting lateral to the coracoid process. This maneuver recreates the anatomic orientation of the trapezoid ligament. Next, the shuttling sutures are used to pass the allograft around both the clavicle and coracoid. The graft is first passed posterior to the clavicle, enters the subcoracoid space medial to the coracoid, and is retrieved out the AIL portal, thus re-creating the conoid ligament. With the second shuttling suture, the graft is next shuttled from inferior to superior; it is passed under the coracoid process and through the soft tissue lateral to the coracoid, and exits anterior to the clavicle ( Fig. 12A.3 ), thus re-creating the trapezoid ligament.

At this point, both the graft and the CC fixation device are secured. The knotless CC fixation device can be retensioned, and an inferior force may be applied to the clavicle to ensure its reduction into anatomic position. The CC fixation device contains a self-locking mechanism, so no knots are required on the top of the clavicle; thus minimizing soft-tissue irritation for the patient. Next, the ends of the graft are placed over the superior aspect of the clavicle and secured with a simple overhand throw stitch using nonabsorbable sutures. The free ends of the graft are sharply cut. This completes the repair, and wound closure is performed to finish the surgery ( Fig. 12A.4 ).

Postoperative Rehabilitation and Return to Sport

See Table 12A.1 .

Phase III: Muscular Strength

The rehabilitation goals of phase III consist of advancing muscular strength by means of resisted initial open and closed kinetic chain exercises, generally introduced at weeks 8 and 10, respectively. Introduced first are isotonic exercises to strengthen the rotator cuff and periscapular musculature ( Figs. 12A.5 and 12A.6 ) using light band or dumbbell resistance with emphasis on controlled eccentric and concentric motion. Closed kinetic chain exercises are initiated in positions of low-load weight bearing through the upper extremities in a fixed position. Once scapular stability and strength of the involved upper extremity has improved to 90% of that of the uninvolved upper extremity in all planes, transition to phase IV is appropriate.

Outcomes

Surgical techniques for arthroscopic fixation of AC joint separations vary substantially, and so far, there is no gold standard of treatment. As recently as 2013, identified 162 surgical techniques for AC joint reconstruction in a systematic review of the literature. The potential advantages of arthroscopically assisted procedures include minimal invasiveness, better visualization, and ability to diagnose and treat concomitant glenohumeral pathologies that frequently occur with higher-grade AC injuries.

investigated outcomes for arthroscopic AC joint fixation with a knotted CC fixation device (AC TightRope, Arthrex). Twelve patients with Rockwood type IV or V injuries underwent surgical fixation, and final outcomes were obtained at approximately 2 years postoperatively. All patients had more than 110 degrees of total elevation and mean Simple Shoulder Test (SST) scores of 11 out of 12. Of the patients not lost to follow-up, all were satisfied and experienced no subjective functional deterioration. Radiographically, there were two failures of reduction and one loss of reduction ( ). Comparable results were found by , who also investigated clinical outcomes following arthroscopic AC joint fixation with a single knotted CC fixation device (AC TightRope, Arthrex). Eighteen patients were included with Rockwood type III, IV, and V injuries. Six patients experienced loss of reduction following surgery; however, Constant scores were not significantly different between patients with loss of reduction and those in whom reduction was maintained (95.6 vs. 98.4, respectively).

The previous studies demonstrate that as with other surgical techniques, it is not uncommon to see complications and loss of reduction following AC joint stabilization surgery. A systematic review performed by found that loss of reduction occurs in 26.8% of patients who underwent arthroscopic fixation for AC joint injury. prospectively investigated outcomes for arthroscopic AC joint fixation with multiple techniques in 116 patients. They found an overall complication rate of 22.4%; the complications included loss of reduction, coracoid fracture, adhesive capsulitis, infection, and persistent pain. However, among patients who did not experience complications, good to excellent outcomes were reported (Constant score 91).

Given the frequency of loss of reduction with AC joint fixation, we believe that additional fixation can help reduce the risk of this complication. This is why our preferred surgical technique utilizes CC fixation along with tendon allograft augmentation; this technique was developed on the basis of outcome results at our own institution, where reported 2-year outcomes following anatomic CC ligament reconstruction for AC joint dislocations in 31 patients. In this study, the arthroscopic surgical technique utilized a single knotted graft through two bone tunnels of the distal clavicle with no additional fixation. One-fifth of patients experienced complications including graft rupture, clavicle fracture, distal clavicle hypertrophy, and adhesive capsulitis. However, patients without complications experienced excellent postoperative outcomes with the following mean scores: American Shoulder and Elbow Surgeons (ASES) score 93.8, Single Assessment Numeric Evaluation (SANE) score 89.1, Quick Disabilities of Arm, Shoulder & Hand (QuickDASH) score 5.6, and patient satisfaction rating 9 out of 10.