Surgical Treatment: Arthroscopic
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
Injuries to the acromioclavicular (AC) joint are common shoulder injuries with an incidence of 1.8/1000 per year ( ).
The majority of AC injuries occur in athletes from contact sports as a result of collision or direct fall onto the shoulder.
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 ( ).
Rockwood and colleagues developed the classification scheme for AC joint injuries, recognizing the importance of the coracoclavicular (CC) ligaments in joint stability ( ).
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.
Our preferred surgical technique involves a knotless fixation system because it can reduce irritation of the subcutaneous tissue.
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 ( ).
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.
Nonoperative management is usually the preferred initial treatment for Rockwood types I and II injuries. Treatment of type III has historically been controversial; however, a new subclassification provides evidence supporting nonoperative treatment of Rockwood type IIIA (horizontally stable) and surgical reconstruction of type IIIB (horizontally unstable) ( ). Acute and chronic Rockwood type IV through VI injuries should also be treated surgically, as should symptomatic type IIIA injuries for which conservative management has failed ( ).
Patient Positioning and Anesthesia
Following induction of general endotracheal anesthesia, the patient is placed in the beach-chair position. Intraoperative fluoroscopy is positioned with the x-ray tube anterior to the patient’s shoulder; this positioning permits utilization of fluoroscopy throughout the procedure to assist with visualization of the bony structures, confirmation of AC joint reduction, and placement of hardware. The patient and fluoroscopy machine are then prepared and draped in sterile fashion with the operative extremity placed in a pneumatic arm holder. Single-shot intravenous antibiotics are administered prior to the incision.
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(s)||Approximate Time Postoperatively||Description|
|I: protection||First 4–6 weeks||Sling immobilization with abduction pillow |
Glenohumeral joint PROM
|II: muscular endurance||Weeks 4–6 to weeks 8–10||Sling discontinued |
Glenohumeral joint AAROM and AROM
|III: muscular strength||Weeks 8–10 to week 16||Week 8: resisted open kinetic chain exercise |
Week 10: resisted closed kinetic chain exercise
Patient progresses to phase IV once strength has reached 90% of uninvolved upper extremity
|IV and V: muscular power and return to sport||Weeks 16–20||Double and single arm plyometrics |
Sport-specific training initiated
Once full restoration of strength and stability is achieved, patient returns to sport
Precautions after AC joint reconstruction surgery include avoidance of passive and active traction to the shoulder girdle, of downward force on the repair for 6 weeks, and of heavy lifting or carrying for 12 weeks. Physical therapists and patients should avoid internal rotation behind the back and horizontal adduction for 8 weeks. AC joint mobilizations should not be performed for 8 weeks, and then only as indicated. Patients are not allowed to begin bench presses or full pushups until 12 weeks postoperatively.
Phase I: Protection
The patient is immobilized in a sling with abduction pillow for 4 to 6 weeks positioned in the scapular plane to unload the reconstructed AC joint. Full passive range of motion (PROM) of the glenohumeral joint is initiated postoperative day 1; it is not uncommon to restrict PROM forward elevation and abduction to 90 degrees for the first 2 postoperative weeks. The patient may also begin full active range of motion (AROM) of the cervical spine, elbow, wrist, and hand as well as neuromuscular re-education scapular exercises on postoperative day 1.
Phase II: Muscular Endurance
Active assisted range of motion (AAROM) and active range of motion (AROM) are initiated between 4 and 6 weeks postoperatively; PROM should be continued during this phase until full ROM is achieved. AAROM and AROM exercises focusing on the glenohumeral and scapulothoracic joint musculature are initiated with the patient in supine, prone, and sidelying positions in order to reduce load on the AC reconstruction. It is paramount to establish normal scapulohumeral rhythm throughout full AROM in all planes during this phase prior to progression to initial strengthening in phase III.
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.
Phase IV and Phase V: Muscular Power and Return To Sport
The rehabilitation goals of phase IV consist of establishing muscular power to return to high-level occupations or athletics, generally introduced at week 16. Supervised throwing progressions and sport-specific training are also incorporated at this time. Patients are allowed to return to sport between 16 and 20 weeks postoperatively if they have achieved full restoration of strength and stability as assessed by functional testing and have received physician approval.
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.
Surgical Treatment: Open
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 open surgical treatment.
Keywords: Acromioclavicular joint, AC joint, AC joint arthrotomy, AC joint reconstruction, Open Surgery for AC Joint Injury, Shoulder Separation
Acromioclavicular (AC) joint injuries are encountered with great frequency in the practice of sports medicine. Although AC injuries encompass 9% of all shoulder injuries in the general population ( ), they are even more common in contact athletes, accounting for 40% of shoulder injuries in collegiate and professional football players ( ). AC injuries are not unique to football; they are the third most common injury in Division I college hockey ( ). Epidemiologic studies estimate the incidence of complete dislocations (Rockwood types III–VI) at approximately 60,000 new cases yearly in the United States ( ). In a study of a physically active United States Military Academy population, the vast majority (89%) of AC injuries sustained by cadets were low-grade (Rockwood type I or II) ( ). Males were twice as likely as females to sustain AC injuries, with male intercollegiate athletes being at the highest risk. With this prevalence in mind, it is important to understand the nonoperative (discussed elsewhere) and operative treatment options for AC injuries. This chapter reviews the operative indications, techniques, results, and complications of open operative management of AC injuries.
Indications for Surgery
Despite years of research on the subject, the optimal role of surgery in the treatment of AC joint injuries remains controversial. Surgery is clearly indicated for treatment of acute Rockwood type IV, V, and VI AC dislocations to prevent long-term shoulder pain and dysfunction ( ). Patients with persistent AC pain and instability after nonoperative treatment for type III AC injuries are indicated for surgical intervention as well. Significantly more debate exists regarding the treatment of acute type III injuries. The current trend is toward initial nonoperative management of type III injuries during season because many authors have obtained good to excellent results with this treatment approach ( ). However, up to 20% of patients with type III AC injuries treated nonoperatively have persistent pain and instability requiring delayed surgical treatment ( ). In addition, studies have shown improved clinical outcomes after early versus delayed reconstruction for type III dislocations ( ). A more detailed addendum to the Rockwood classification suggested the separation of Rockwood grade III into grade IIIA and grade IIIB injuries regarding horizontal instability. Although grade IIIA injuries demonstrate horizontal instability, the posteriorly unstable grade IIIB injury demonstrates overriding of the clavicle on a cross-body adduction radiograph and would more likely result in a therapy-resistant scapular dysfunction ( ). We recommend a patient-centered approach to type III injuries, in which the patient’s occupation, hand dominance, job or sport requirements, and risk of reinjury are all considered. High-demand laborers and athletes (i.e., throwing, contact) should be considered for acute surgical intervention for Rockwood type III because of the risk of persistent pain and instability. Acute type III AC injuries in high-demand patients may be considered a relative indication for early operative intervention.
Goals of Surgery
Regardless of the technique, the main goal of treatment for AC injuries is to obtain a pain-free shoulder with unrestricted range of motion and full strength, without any limitations in activity. To obtain these goals, a set of crucial elements should be addressed during operative treatment of AC injuries: (1) correction of the superior displacement and anterior-to-posterior translation of the clavicle through anatomic reduction of the AC joint, (2) maintenance of AC joint stability during acute healing by supplementation of the coracoclavicular (CC) ligament reconstruction with a synthetic material or rigid implant or reconstructing the CC ligaments in a chronic case, and (3) meticulous deltotrapezial fascia closure.
Historical Perspective on Open Treatment Options
Since the first operative treatment for an AC joint injury was reported by , well over 150 different operative techniques for AC joint injuries have been described ( ). The vast number of procedures can be broken down broadly into three general categories: primary AC fixation, coracoclavicular fixation, and anatomic or nonanatomic ligament reconstruction. The first surgical approaches used Steinmann pins or K-wires to reduce the AC joint. These constructs resulted in a high failure rate of the stiff construct because of hardware failure or migration. This was followed by a time of distal clavicle resection as a treatment option, which did not result in improving the patient’s outcome and satisfaction because pain caused by residual instability remained. Although a multitude of surgeries have been described, the modified Weaver-Dunn procedure has been the most popular technique until recently. In 1972, Weaver and Dunn first described open treatment of acute and chronic AC injuries using transfer of the coracoacromial ligament from the acromion to the clavicle ( ). Their technique was modified to allow for distal clavicle resection to prevent symptomatic arthrosis at the AC joint and later by the addition of coracoclavicular fixation ( ). A major challenge facing this operation has been maintenance of reduction, and this is likely secondary to the transferred CA ligament lacking the strength of the native CC ligaments and inadequately reproducing their normal anatomy. This deficiency led to the development of the anatomic coracoclavicular reconstruction (ACCR), which aims to recreate the anatomy of the coracoclavicular ligaments while using stronger graft materials ( ).
Senior Author’s Preferred Technique: Anatomic Coracoclavicular Reconstruction
Anatomy and Biomechanics
The primary static stabilizers of the AC joint include the AC ligaments and coracoclavicular ligaments. The AC ligaments are the primary restraints to horizontal instability of the distal clavicle, with the superior ligament providing 56% of the resistance to posterior translation and the posterior ligament contributing 25%. The coracoclavicular ligaments are the primary restraint to vertical instability, with the conoid ligament specifically providing 60% of the resistance to superior translation of the clavicle ( ). The trapezoid and conoid ligaments both originate posterior to the pectoralis minor insertion on the coracoid and traverse the coracoclavicular interspace. The conoid inserts onto the posteroinferior clavicle approximately 46 mm medial to the AC joint. The trapezoid inserts 26 mm medially to the AC joint and more centrally in the anteroposterior dimension ( ).
The author’s preferred technique for treatment of operative AC joint injuries is the ACCR. This surgical technique attempts to reconstruct the appropriate anatomy and biomechanics of the AC joint and coracoclavicular space, with the goal of restoring both vertical and horizontal stability to the AC joint. In the ACCR, the conoid and trapezoid ligaments are reconstructed using autograft or allograft tendon tissue, with reconstruction of the AC joint capsular ligaments. Fixation of the graft to the clavicle is performed using interference screws, but fixation of the graft to the coracoid can be performed one of two ways. The tendon graft may be passed around the coracoid base with the loop technique, or it may be fixed to the coracoid with an interference screw in the tenodesis technique. The tendon graft is supplemented with nonbiologic fixation in the form of high-strength nonabsorbable suture (no. 2 FiberWire, Arthrex). The biomechanical advantage of the anatomic coracoclavicular ligament reconstruction has been demonstrated in multiple studies. found that anatomic CC reconstruction with allograft had a significantly higher load to failure than modified Weaver-Dunn, anatomic suture, nonanatomic allograft, and GraftRope techniques. Although the ACCR can be performed via an arthroscopic approach ( ), the open approach using a loop technique is the author’s preference and will be described here.
The importance of proper patient positioning should not be overlooked because it is a crucial step in this surgery. The patient is placed in the beach-chair position, with the torso and operative extremity brought to the edge of the surgical table ( Fig. 12B.1 ). A small radiolucent bump placed at the medial border of the scapula will serve to stabilize the scapula and elevate the coracoid anteriorly. The patient’s head should be secured in the beach-chair position, but it should not be firmly taped to the table as repositioning of the head is occasionally necessary during drilling of the medial clavicular bone tunnel. Before prepping and draping, the mini-C-arm should be trialed to ensure appropriate biplanar fluoroscopic imaging of the clavicle can be obtained. The operative arm is draped free to allow for easy maneuverability and reduction of the AC joint.
Beginning laterally at the posterior clavicle and gently angling toward the coracoid process, a curvilinear skin incision is made along the Langer lines and centered approximately 3 cm medial to the AC joint. Full-thickness cutaneous flaps are elevated to expose the underlying deltotrapezial fascia ( Fig. 12B.2 ). The raphe between the clavicular attachments of the deltoid and trapezius provides a relatively avascular plane for dissection. Deltotrapezial fascioperiosteal flaps are then elevated posteriorly and anteriorly from the midline of the clavicle to circumferentially expose the lateral end of the clavicle and the AC joint laterally. It is important to elevate the entirety of the deltoid origin circumferential from the clavicle, including the inferior aspect, to allow for a full-thickness robust repair at the time of wound closure. Tagging sutures may be placed during the approach to allow for retraction during dissection and effective soft tissue coverage over the repair upon closure.
Graft Selection and Preparation
An allograft (typically peroneus longus) or autograft (typically semitendinosus or gracilis) tendon can be used for this procedure. A standard tendon sizer is used to size the tendon, which is usually 5 mm in size. The graft size determines the size of the drill holes. The tendon graft should be prepared with as much length as possible to allow for later reconstruction of the AC capsule–ligament complex. The free tendon ends are then bulleted, and a whip stitch is placed to allow for a tight passage through the bone tunnels.
As mentioned earlier, the tendon graft can be secured to the coracoid by either looping the graft around the base of the coracoid (loop technique) or by a tenodesis technique with the graft secured to the base of the coracoid with an interference screw. The loop technique is described here because it is our preferred technique. The coracoid process is first exposed with soft tissue dissection, with clear delineation of its medial and lateral margins ( Fig. 12B.3 ). Importantly, the surgeon should not dissect too far into the posterior direction on the coracoid base because the suprascapular nerve is in close relationship. A Stanitsky aortic cross-clamp, or alternatively, a suture-passing device, is then passed in a medial to lateral direction around the coracoid process. A suture is fed around the base of the coracoid, and a loop is created at one of its free ends. The suture loop is then used to shuttle the prepared tendon graft, along with a supplemental collagen coated no. 2 FiberWire suture, around the base of the coracoid.
Clavicle Preparation and Tunnel Placement
Next, attention is turned to creating bone tunnels in the clavicle for fixation of the tendon graft to recreate the anatomic location of the conoid and trapezoid ligaments. A guide pin is drilled approximately 45 mm medial from the distal end of the clavicle ( Fig. 12B.4 ). The conoid tubercle on the inferior surface of the lateral third clavicle marks the attachment of the conoid ligament and can serve as an anatomic landmark during guide pin placement. The guide pin should be placed posteriorly in the clavicle to recreate anatomy, but care should be taken to avoid disruption of the posterior cortical rim during subsequent reaming. A 5-mm cannulated reamer (assuming a 5-mm tendon graft) is used on power over the guide pin to create the bone tunnel for the conoid graft limb. The reamer is removed from the bone tunnel by hand to ensure the tunnel remains a perfect circle and is not widened by eccentric reaming. After reaming, a hand-powered tap 0.5 mm wider than the drill is introduced. The depth of the tunnel is measured for appropriate tenodesis screw length placement. The trapezoid ligament reconstruction bone tunnel is then created by placing a guide pin approximately 15 to 20 mm lateral to the conoid tunnel and centered in the clavicle in the anterior-to-posterior plane. The trapezoid bone tunnel should be 25 to 30 mm medial to the AC joint, and it is drilled and measured in an identical fashion to the conoid tunnel. We have demonstrated in our laboratory that the bone mineral density of the distal clavicle decreases more laterally, which can negatively affect the fixation strength and graft pullout.
The free limbs of the graft can be passed through the bone tunnels in a crossed (figure of eight) or a noncrossed fashion (U loop). In our technique, the noncrossed U-loop graft is passed through the tunnels if there is predominantly posterior displacement of the clavicle, and the crossed figure-of-eight configuration is used if there is just superior displacement. An end of the nonabsorbable suture (no. 2 FiberWire) accompanies each limb of the tendon graft through the bone tunnels ( Fig. 12B.5 ). Reduction of the AC joint is then performed by applying an upward force to the elbow or arm. In addition to the superior-inferior reduction, care should be taken to adequately reduce the distal clavicle in the anteroposterior direction as well. The reduction is held using a large pointed reduction forceps placed between the coracoid process and the clavicle. Fluoroscopy is used to confirm anatomic reduction of the AC joint as well as the visualization of the exposed AC joint. The conoid limb of the graft is secured first. The graft is positioned so that the graft tail is left 2 cm proud from the superior aspect of the clavicle. The long tail of the graft exits the trapezoid tunnel laterally and is later used to augment the AC joint repair. A nonabsorbable radiolucent screw of the appropriate size and length (usually a 5.5-mm × 10- to 12-mm PEEK interference screw) is placed in the conoid tunnel. While holding reduction of the AC joint and traction on the graft, a second nonabsorbable radiolucent (5.5-mm PEEK) screw is placed in the lateral trapezoid bone tunnel anterior to the tendon graft. With the graft secure, the no. 2 FiberWire ends are tied over the top of the clavicle to provide nonbiologic augmentation of the repair. The pointed reduction forceps can then be removed and fluoroscopic images taken to confirm reduction of the AC joint.
Acromioclavicular Joint Repair and Closure
An AC joint repair is performed in the setting of acute AC joint dislocations. A no. 0 nonabsorbable suture is used in simple or figure-of-eight fashion to repair the AC joint capsule and ligaments primarily. The posterior and superior AC ligaments are crucial to the repair because they contribute significantly to resisting posterior and superior displacement of the clavicle. The long limb of the graft exiting the trapezoid tunnel is then taken laterally and looped on top of the AC joint to augment the capsule repair. The 2-cm graft tail exiting the conoid tunnel is folded lateral and sutured into the base of the graft exiting the trapezoid tunnel.
In chronic dislocations, the AC joint can also be repaired as described earlier.
After the AC joint repair is completed, the excess tendon graft is trimmed. Meticulous closure of the deltotrapezial fascia is performed using interrupted nonabsorbable sutures followed by 3-0 Monocryl subcutaneous closure and running subcuticular closure.
Postoperatively, patients are placed in a platform brace (DonJoy Lerman Shoulder Orthosis or Hangar Gunslinger Shoulder Orthosis) and remain immobilized in the brace for approximately 8 weeks. The platform brace supports the arm and minimizes the gravity-induced stress on the AC joint reconstruction. With the arm unsupported, the surgical repair experiences a large amount of stress as the AC joint is the only link connecting the upper extremity to the thorax (via the clavicle). During the first 3 months after open ACCR, activities that increase the stress on the repair site should be avoided. This protocol is based on the fact that tendon graft in a bone tunnel requires up to 12 weeks before achieving strong union at the bone–tendon interface, so the strength of the construct is predominantly dependent on the biomechanical properties of the repair during this time. After 8 weeks of immobilization, patients are referred to formal physical therapy. The early focus (weeks 8–12) of physical therapy is restoring shoulder range of motion and scapular control. Closed-chain (limb-supported) exercises are initiated first, with a transition to open chain exercises as mobility improves. Caution is used with range of motion exercises that increase stress on the AC joint, such as internal rotation behind the back, cross-body adduction, and end-range forward elevation. Rehabilitation shifts from mobility to strengthening and control during weeks 12 to 18. Scapular strengthening exercises include low rowing, horizontal abduction with external rotation, and prone horizontal extension with the arm at 100 degrees abduction ( ). For athletes in particular, weight training may begin at 3 to 5 months postoperatively. Athletes are allowed to return to full contact sports at 6 months. Athletes should be counseled that it generally requires 9 to 12 months to regain peak strength, particularly with bench press and deadlift type exercises ( ).
Although level 1 comparative studies and long-term outcomes data on ACCR are currently lacking from the literature, the open ACCR technique described earlier is thought to be a valuable addition to the treatment armamentarium for both acute and chronic AC dislocations. Short- and midterm clinical outcomes studies have demonstrated that the majority of patients experience significant relief of pain, return of normal strength and function, and negligible loss of motion. recently reviewed the clinical outcomes of 31 patients at a minimum of 2 years after primary ACCR with tendon grafts. The authors found excellent postoperative outcomes scores (American Shoulder and Elbow Surgeon [ASES], Single Assessment Numeric Evaluation score [SANE], quick Disabilities of the Arm, Shoulder and Hand score [quickDASH], and patient satisfaction) in the 20 patients available for follow-up beyond 2 years (mean, 3.5 years) who had not undergone revision surgery. In an analysis of 59 shoulders after ACCR, found construct survivorship rates of 86.2% and 83.2% at 12 and 24 months, respectively. In addition, they noted a significant improvement in the postoperative ASES and Short Form 12 physical component scores at a mean follow-up of 2.4 years. Several other smaller series demonstrate similar results with high patient satisfaction rates and significantly improved outcome scores ( ). Although most of these studies involved young active patients, there are no known studies investigating return to sport and patient outcomes specifically in athletes after ACCR.
As with any procedure, open ACCR presents risks that must be considered when discussing treatment options with patients. Complications after open ACCR have been reported with varying frequency in the literature. reported an 18% complication rate (3 of 17 patients), which included 1 infection, 1 radiographic loss of reduction, and 1 patient with chronic AC joint pain. In a retrospective analysis of 27 patients, reported a much higher complication rate of 52% (14 or 27 patients), including fractures of the clavicle and coracoid, infection, and adhesive capsulitis. The most common complication, however, was radiographic loss of reduction (43% of reported complications), and this was not correlated to clinical outcomes in the study. Thirteen complications (28%) occurred in a series of 46 patients with ACCR using tendon grafts by , including 4 graft ruptures, 2 clavicle fractures, and 2 cases of painful hardware. The remaining complications included individual cases of hardware failure, hypertrophic distal clavicle, suture granuloma, adhesive capsulitis, and axillary neuropathy. and more recently have found that medialization of the clavicular bone tunnels is a risk factor for radiographic loss of reduction. The risk of clavicle fracture after ACCR has been an area of specific interest. In their biomechanical study, demonstrated that large (6.0-mm) bone tunnels significantly reduce the strength of the clavicle and may contribute to postoperative clavicle fractures. Technical pearls for avoiding coracoid and clavicle fractures include using the loop technique for coracoid fixation, creating smaller (5-mm) clavicular bone tunnels, maintaining sufficient distance between bone tunnels, and avoiding bone tunnels in the lateral 15 mm of the clavicle ( ).
Open treatment of AC injuries continues to evolve. ACCR described in this chapter has attempted to improve on previous techniques by restoring the anatomy of the coracoclavicular ligaments and creating a biomechanically superior construct. It is indicated for acute or chronic Rockwood type IV to VI AC injuries, chronic type III AC injuries, and acute type III AC injuries on a case-by-case basis. Midterm outcomes are promising with regards to patient satisfaction and clinical outcomes scores. Further studies are required to investigate long-term outcomes, athlete-specific outcomes, and methods to decrease the postoperative complication rate.
The treatment of acromioclavicular (AC) injuries continues to evolve. Many surgical techniques in treating high-grade AC joint separations have been described. The latest techniques aim to reconstruct the coracoclavicular (CC) ligaments anatomically in order to provide biologic healing without the complications associated with retained hardware. Arthroscopically assisted techniques continue to develop, particularly in the treatment of acute injuries. At this time, no gold standard treatment exists, and outcomes remain conflicted despite advancements in techniques.
Keywords: acromioclavicular joint, acromioclavicular dislocation, anatomic reconstruction, arthroscopically assisted
The acromioclavicular (AC) joint is commonly involved in traumatic injuries to the shoulder, up to 12% of all shoulder injuries ( ).
These injuries often occur in younger, athletic patients. One report examining collegiate football players showed AC injuries to account for 41% of all shoulder injuries ( ).
Despite the high prevalence of AC joint injuries, their treatment remains a continued source of debate.
A multitude of surgical techniques have been described, and outcomes of operative treatment remain variable, despite continued advancements.
AC joint dislocation most commonly occurs after a direct blow onto the superior aspect of the shoulder. The most commonly used classification system remains the Rockwood classification, which reflects increasing levels of injury to the AC and coracoclavicular (CC) ligaments ( ). A type I injury describes a sprain of the AC joint capsule, whereas a type II injury reflects a complete disruption of the joint capsule. Type III injury is a superiorly displaced distal clavicle due to rupture of the CC ligaments. In type IV injuries the clavicle is positioned posteriorly, and a type V injury features further superior displacement than a type III due to disruption and incarceration of the clavicle above the deltotrapezial fascia. Type VI injuries are rare and result in inferior dislocation of the distal clavicle into a subacromial or subcoracoid position. Low-grade injuries (types I and II) have been thought to occur twice as frequently as high-grade injuries (types III–VI) ( ).
Although the position of the distal clavicle is the focus in the diagnosis and classification of an AC separation, this approach is actually opposite to how we typically describe other joint dislocations. The distal (displaced) segment in an AC separation is the scapula, which can have inferior displacement ( Fig. 12C.1 ), downward rotation, anterior displacement ( Figs. 12C.2 and 12C.3 ), and internal rotation. The suspension of the scapula and upper extremity to the clavicle relies primarily on the CC ligaments and secondarily on the AC ligaments and surrounding musculature ( ). The dissociation seen in high-grade AC injuries can cause altered scapular mechanics and dysfunction of the shoulder ( ).