Amir Mostofi, Augustus D. Mazzocca, and Robert A. Arciero
DEFINITION
About 9% of shoulder girdle injuries involve damage to the acromioclavicular (AC) joint.
This is a sequential injury beginning with the AC ligaments, progressing to the coracoclavicular ligaments, and finally involving the deltoid and trapezial muscles and fascia.
Patients usually report direct trauma to the lateral shoulder or a fall on an outstretched arm driving the humeral head into the AC joint, resulting in a dislocation with pain at the AC joint, in particular with cross-arm adduction.
Dislocations are classified by severity of injury, radiographic findings, and position of the clavicle12 (Table 1).
ANATOMY
The AC joint is a diarthrodial joint that primarily rotates as well as translates in the anteroposterior as well the superoinferior plane.
The scapula (acromion) can protract and retract, using the AC joint as a pivot point.
Normal scapular motion consists of substantial rotations around three axes and plays a major role in the motion at the AC joint.
The articular surface is made up of hyaline cartilage containing an intra-articular meniscus type of structure, all surrounded by a joint capsule with a synovial lining.
The AC joint static stabilizers include the acromioclavicular ligaments (superior, inferior, anterior, and posterior), the coracoclavicular ligaments (trapezoid and conoid), and the coracoacromial (CA) ligament.
The AC joint dynamic stabilizers consist of the deltoid and trapezius muscles.
Appreciating the location of the coracoclavicular ligament attachment on the clavicle is important. The trapezoid 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. Both the trapezoid and conoid are posterior to the pectoralis minor attachment on the coracoid (FIG 1).
The AC joint capsule and the capsular ligaments are the primary restraints of the distal clavicle to anterior-to-posterior translation. More specifically, the superior and posterior AC capsular ligaments prevent posterior displacement of the clavicle and abutment against the scapular spine.5
The trapezoid and conoid span the coracoclavicular space (1.1 to 1.3 cm) and contribute to vertical stability, preventing superior and inferior translation of the clavicle.
The AC and coracoclavicular ligaments all contribute to the prevention of motion in all planes. The conoid ligament has the highest in situ forces with superior loads, regardless of the integrity of the AC ligaments. The AC ligaments are the main restraints to posterior and anterior translation. However, when the AC ligaments are transected, the conoid is the primary restraint to anterior loads and the trapezoid is the primary restraint to posterior loads.3
The AC joint is innervated by the lateral pectoral nerve and the suprascapular nerve.
PATHOGENESIS
The mechanism of most AC joint injuries is a direct blow to the lateral acromion with the arm adducted.
Indirect injury occurs by falling on an adducted outstretched hand or elbow, causing the humeral head to translocate superiorly and drive the humeral head into the acromion.
NATURAL HISTORY
Most patients with type I or II AC joint separations typically have full recovery with no long-term sequelae. However, some patients continue to be symptomatic. In one study, up to 27% of patients with type I and II injuries had persistent pain and required a surgical procedure. Some patients treated nonoperatively continued to have instability and pain with provocative tests (level IV evidence).7
Most patients with type III separations do well with conservative treatment. In a survey of Major League Baseball team physicians, 80% of athletes treated nonoperatively had complete pain relief and normal function (level IV evidence).6 Studies have failed to show a statistical difference in the return to activity (level IV evidence).8
Type IV, V, and VI AC joint separations do poorly without operative intervention (level V evidence).2 Persistent pain is attributed to a chronically dislocated AC joint with severe soft tissue disruption.
PATIENT HISTORY AND PHYSICAL FINDINGS
The mechanism of injury is an important history finding that clues one into a possible AC joint injury.
Pain at the AC joint is difficult to differentiate from glenohumeral pathology because of the dual innervation of the AC joint by the lateral pectoral nerve and suprascapular nerve.
Because of the innervation by the lateral pectoral nerve, some patients may present with anteromedial pain, further complicating the picture.
Pain in the trapezius region and anterolateral deltoid is more specific for AC joint injury, whereas pain located only in the lateral deltoid is more indicative of a subacromial process.
Pathology of the AC joint is identified by a triad of point tenderness, positive pain at the AC joint with cross-arm adduction, and relief of symptoms by injection of a local anesthetic.
Methods for examining the AC joint include the following.
AC joint compression (shear) test: Isolated painful movement at the AC joint in conjunction with a history of direct trauma indicates AC joint pathology.
Cross-arm adduction test: Look for pain specifically at the AC joint. Pain at posterior aspect of shoulder or lateral shoulder might indicate other pathology.
Paxinos test16 is sometimes done in conjunction with bone scan to assess damage to AC joint.
O'Brien test: Symptoms at the top of the joint must be confirmed by examiner palpating the AC joint. Anterior glenohumeral joint pain suggests labral or biceps pathology.
Local point tenderness at the AC joint while keeping the glenohumeral joint still is suspicious for localized AC joint pathology.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Standard radiographs include AP, supraspinatus outlet view (FIG 2A), and axillary and Zanca views.
A Zanca view is made by tilting the x-ray beam 10 to 15 degrees toward the cephalic direction (FIG 2B,C).
The AC joint is more superficial and surrounded by less soft tissue than the glenohumeral joint.
FIG 1 • A. Anterior view. The trapezoid is anterolateral, whereas the conoid is a posteromedial structure. B. Posterior view. The conoid can be seen as a broad ligament that fans out, attaching to the clavicle in a posteromedial position.
The AC joint may be better visualized if a reduced penetration strength is used compared to standard radiographs of the glenohumeral joint.
An axial view of the shoulder is important in differentiating a type III from a type IV AC joint injury.
Coracoid base fractures can also be identified on this view.
A normal coracoclavicular interspace, in conjunction with a complete dislocation of the AC joint, may indicate a coracoid fracture, in which case a Stryker notch view is helpful (FIG 2D).
The AC joint width is normally 1 to 3 mm and decreases with age. The width seen on radiographs is influenced by the individual variability of obliquity of the joint in relation to the x-ray beam.
An increase in the coracoclavicular distance (usually 1.3 cm) of 25% to 50% over the normal side indicates complete coracoclavicular ligament disruption.
Although seldom necessary and mainly a historical practice, stress views (5 to 10 pounds placed in the ipsilateral hand) with increased coracoclavicular interspace on the AP view may help differentiate between type II and type III injuries.
Bone scan may help confirm subtle AC joint pathology and arthrosis.
DIFFERENTIAL DIAGNOSIS
Cervical spine pathology
Trapezial spasm
Scapular dyskinesia
Hyperlaxity
Distal clavicle or acromion fracture
Coracoid fracture
FIG 2 • Positioning for radiographic studies. A. Supraspinatus outlet view. B,C. Zanca view. For optimal visualization of the acromioclavicular joint, the x-ray source is directed 10 degrees cephalad with reduced penetration strength compared to a standard radiograph. D. Stryker notch view. This view helps rule out concomitant injuries. It is helpful when a coracoid fracture is suspected with a normal coracoclavicular interspace.
Glenohumeral pathology (impingement, rotator cuff, HillSachs, Bankart, superior labral anterior posterior [SLAP] lesion, biceps)
Ulnar paresthesias
Thoracic outlet syndrome
NONOPERATIVE MANAGEMENT
The main goals of treatment, whether surgical or nonsurgical, are to achieve a pain-free shoulder with full range of motion and strength and no limitations in activities.
Most type I and type II AC joint separations are treated in a nonoperative fashion.
Treatment begins with a sling, ice, and a brief period of immobilization only for pain control. Rehabilitation is started as soon as tolerated.
The rehabilitation program consists of four phases:4
Pain control, immediate protective range of motion and isometric exercises
Strengthening exercises using isotonic contractions
Unrestricted functional participation with the goal of increasing strength, power, endurance, and neuromuscular control
Return to activity with sports-specific functional drills
Surgical intervention should be considered after rehabilitation if pain persists for greater than 3 months.
Type III injuries:
These patients are usually evaluated on a case-by-case basis, taking into account hand dominance, occupation, heavy labor, position and sport requirements (quarterbacks, pitchers), scapulothoracic dysfunction, and risk for re-injury.
In a meta-analysis of 1172 patients, 88% of those treated with surgery and 87% of those treated without surgery had satisfactory outcomes (level IV evidence).8
In patients with type III injuries treated nonoperatively versus operatively, there was no difference in strength at 2 years of follow-up (level IV evidence).14
Schlegel and Burks13 found that only 20% of patients reported a suboptimal outcome with conservative care. Objective studies showed that patients had no limitation of shoulder motion in the injured extremity and no difference compared with the unaffected extremity in rotational shoulder muscle strength. A finding that may affect heavy laborers was a decrease of 17% in bench press strength at the 1-year follow-up (level IV evidence).
If symptoms persist for greater than 3 months, including increased pain, impingement due to scapular dyskinesia, decreased strength, inability to get the arm into a cocking position in throwing, and painful instability, especially posterior instability with the clavicle abutting the anterior portion of the spine of the scapula, then operative intervention may be indicated.
SURGICAL MANAGEMENT
Again, the main goals of treatment, whether surgical or nonsurgical, are to achieve a pain-free shoulder with full range of motion and strength and no limitations in activities.
Complete AC joint injuries (type IV, V, and VI) are usually treated operatively because of the significant morbidity associated with persistently dislocated joints and severe soft tissue disruption.
Most surgeons will treat type III injuries conservatively for 12 weeks and consider surgical stabilization if persistent pain and instability exist. In an attempt to return an athlete or highdemand patient to work more rapidly, some will stabilize a type III separation, hoping to decrease painful instability.
Some patients treated nonoperatively will have persistent pain and an inability to return to their sport or job and will require surgical stabilization.
Operative choices:
AC ligament repair
Dynamic muscle transfer
CA ligament transfer
Coracoclavicular ligament repair
Distal clavicle resection with coracoclavicular reconstruction
Distal clavicle resection without coracoclavicular reconstruction
Anatomic reconstruction of the coracoclavicular ligament
Arthroscopic variations of the above
In the treatment of chronic AC joint pain with distal clavicle resection, arthroscopy of the glenohumeral joint can be undertaken to rule out concomitant injuries. Missed SLAP lesions and labral pathology have been reported as a cause of failed distal clavicle resection.1
The modified CA ligament transfer (Weaver-Dunn) is the gold standard of treatment for the reconstruction of the AC joint and is presented here.
Anatomic reconstruction of the coracoclavicular ligaments (ACCR) attempts to recreate the normal anatomy and biomechanics of the AC joint. This technique has been studied in our biomechanics laboratory and is in clinical trials. The ACCR is our procedure of choice and is also presented here.
Various arthroscopic techniques have been described for fixation of AC separations.
A description of an arthroscopic procedure using a highstrength suture and endobutton device is provided.
Although our preferred treatment of acute type III injuries is conservative, this technique may be helpful for surgeons who decide to stabilize and splint acute type III injuries in high-demand patients.
Preoperative Planning
A successful outcome depends on reasonable patient expectations and compliance with the postoperative regimen, including postoperative sling immobilization for 6 weeks.
All radiographs are reviewed.
Reports indicate that concomitant injuries such as SLAP lesions and labral tears are a cause of failure after distal clavicle resection.1
Magnetic resonance imaging (MRI) may be obtained to rule out concomitant injuries that also need to be addressed.
If using a modified Weaver-Dunn or ACCR, the surgeon should discuss with the patient the options for autograft or allograft.
Positioning
The patient is placed in the beach-chair position after induction of general anesthesia (FIG 3).
A specialized shoulder table is not used. We prefer a standard table that provides posterior support and stabilization of the scapula.
A small bump is placed on the medial scapular edge to stabilize it and elevate the coracoid anteriorly.
FIG 3 • The beach-chair position is used, with a small bump placed on the medial scapular edge to bring the coracoid anteriorly and to secure the scapula. The head should be mobile to allow repositioning if needed during clavicle reaming. The arm is free draped from the sternoclavicular joint laterally.
The head is mobile because repositioning is sometimes necessary during medial clavicle drilling.
Wide draping is done to expose the sternoclavicular joint and posterior clavicle for complete visualization of the shoulder girdle.
The arm is free draped to allow free motion and reduction.
Approach
The mean length from the end of the clavicle, or the AC joint, to the coracoclavicular ligaments is 46.3 ± 5 mm; the distance between the trapezoid laterally and the conoid medially is 21.4 ± 4.2 mm.11
In both the Weaver-Dunn and ACCR procedures, the incision is made to allow exposure of the AC joint and coracoid.
The incision for the Weaver-Dunn is more lateral compared to the ACCR because of the exposure necessary for CA ligament acquisition and because the ACCR clavicle preparation is performed slightly more medially.
Again, full exposure of the AC joint and coracoid is necessary in both procedures, and the incision can be extended or curved to allow the necessary exposure.
Although the AC joint and clavicle are superficial structures with little subcutaneous tissue, in our experience large skin flaps can be used to improve visualization without compromising the vascularity of the skin.
Full-thickness flaps of the deltotrapezial fascia during the approach are critical for closure. Tagging sutures can be placed during the approach to allow for quick and effective soft tissue coverage over the repair.
Gelpi retractors are low profile and help retract the deltotrapezial flaps.
TECHNIQUES
ANATOMIC CORACOCLAVICULAR LIGAMENT RECONSTRUCTION
Exposure
Arthroscopy of the glenohumeral joint can be performed to look for concomitant injuries.
An incision is made 3.5 cm from the AC joint starting at the posterior clavicle in a curvilinear fashion toward the coracoid along the lines of Langer.
The incision is sometimes angled because the key is to have full visualization of the AC joint laterally and the coracoid process medially (TECH FIG 1).
Superficial skin bleeders are controlled down to the fascia of the deltoid with a needle-tip Bovie.
Full-thickness flaps are made from the midline of the clavicle both posteriorly and anteriorly, skeletonizing the clavicle.
Tagging sutures are placed in the deltotrapezial fascia.
Traction on the tagging sutures or a Gelpi retractor under the flaps is used for visualization.
The tagging sutures are used for easy and precise closure of the fascia at the end of the procedure.
Once the approach is complete, a trial reduction is attempted.
The distal end of the clavicle may need to be freed from the trapezius muscle, under the acromion, or coracoid.
Interposition of soft tissue may prevent anatomic reduction of the AC joint.
TECH FIG 1 • A curvilinear incision is made 3.5 cm medial to the acromioclavicular joint along the lines of Langer. Visualization of the acromioclavicular joint as well as the coracoid is possible. The deltotrapezial fascia is split along the midline of the clavicle and elevated as two fullthickness flaps.
Graft Preparation
A semitendinosus allograft or autograft or an anterior tibialis allograft can be used for this procedure (TECH FIG 2A). (See the Techniques section of Chap. SM-32 for a description of obtaining a semitendinosus autograft.)
TECH FIG 2 • A. Grafts need tendon-grasping sutures at both ends for ease of passage around the coracoid and through bone tunnels. B. In our alternative method, grafts that are to be fixed to the coracoid are folded so that there is one short limb and one long limb. A no. 2 nonabsorbable suture is placed through the doubled-over tendon graft in a Krakow manner. Tendon ends are bulleted for ease of passage through bone tunnels.
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 graft passage through bone tunnels.
The graft is ready for use if the surgeon is performing our preferred looping method. However, an alternative method is interference screw fixation to the coracoid process.
In this option, the graft is folded with one short limb (about 3 inches) and a limb containing the remaining length of the tendon. A no. 2 ultra-highstrength nonabsorbable suture is placed through the doubled-over tendon graft in a Krakow manner (TECH FIG 2B).
Coracoid Preparation
Standard looping technique
A graft can be looped around the base of the coracoid process using an aortic cross-clamp (Stanitsky clamp) or a suture-passing device (Arthrex, Inc., Naples, FL) for biologic fixation.
A heavy no. 2 ultra-strength nonabsorbable suture is also placed around the coracoid for use as a nonbiologic form fixation (TECH FIG 3A,B).
Alternative technique: interference screw fixation to coracoid (TECH FIG 3C)
TECH FIG 3 • A. The graft is looped around the coracoid. B. A suture passer can be used to safely loop the graft and a nonabsorbable suture around the coracoid base. C. In the alternative technique, a bone tunnel that approximates the diameter of the graft (usually 6 to 7 mm) is made in the coracoid. One limb of the Krakow suture is placed, and the doubled-over tendon is passed through the PEEK screw and driver (top inset). While traction is held with this suture, the tenodesis driver is advanced to touch the tendon graft (bottom inset), and the entire tendon, driver, and screw complex is placed into the coracoid bone tunnel.
Although we currently do not use this method, some may choose to anchor the tendon into the base of the coracoid.
The diameter of the doubled-over portion of the graft is measured with a standard tendon-measuring device. Using this number, the appropriate cannulated reamer is chosen (6 or 7 mm).
The surgeon should use a smaller reamer diameter first and ream up in size if necessary.
Finger palpation of both lateral and medial portions of the coracoid process and drilling into the coracoid base under direct visualization with a cannulated reamer guide pin are completed.
One limb of the Krakow suture is passed through a 5.5 × 8-mm nonabsorbable radiolucent tenodesis screw and driver using a Nitinol wire.
The tenodesis driver is advanced to touch the tendon graft, and the entire tendon, driver, and screw complex is placed into the coracoid bone tunnel until 15 mm of the Krakow suture disappears.
The sutures from the graft are tied together over the existing interference screw, giving both interference screw and suture anchor advantages.
Clavicle Preparation
To recreate the conoid ligament, a cannulated guide pin is placed 45 mm away from the distal end of the clavicle and as posterior as possible, taking into consideration the space needed to not “blow out” the posterior cortical rim during reaming.
A 6-mm cannulated reamer is used to create the tunnel (TECH FIG 4).
If there is a question of what size reamer to use, starting with the smallest reamer necessary is always a good technique; if necessary the surgeon can ream up.
The surgeon reams in under power.
The surgeon disconnects the power driver and pulls the reamer out manually to ensure that the tunnel is a perfect circle and not widened by uneven reaming.
The same procedure is repeated for the trapezoid ligament, which is a more anterior structure than the conoid.
This tunnel is centered on the clavicle, approximately 15 mm lateral of the center portion of the previous tunnel.
Graft Fixation and Reconstruction
The limbs of the graft are crossed over the coracoid and one limb of the biologic graft is placed through the posterior bone tunnel, recreating the conoid ligament.
The other limb is passed through the anterior bone tunnel in the same fashion, recreating the trapezoid ligament (TECH FIG 5).
The no. 2 ultra-high-strength nonabsorbable suture placed around the coracoid is also passed through the tunnels for nonbiologic augmentation of the repair.
Upper displacement of the scapulohumeral complex and the use of a large point-of-reduction forceps placed on the coracoid process and the clavicle by the assistant are used to reduce the AC joint.
Fluoroscopy is used to confirm proper placement of the grafts and reduction of the AC joint.
The graft is pulled on cyclically multiple times and passed through the tunnels back and forth to reduce any displacement that might occur after fixation.
This step is critical to ensure that there is no migration or movement after the fixation is complete.
Nevertheless, we often overreduce the AC joint by 2 to 3 mm with the knowledge that a few millimeters of displacement still occurs.
The graft is positioned so that the graft tail representing the conoid ligament is left 2 cm proud from the superior margin of the clavicle. The long tail of the graft exits the trapezoid tunnel and will later be used to augment the AC joint repair if indicated (see Tech Fig 5).
With traction placed on the graft, ensuring its tautness, a 5.5 × 8-mm nonabsorbable radiolucent screw is placed in the posteromedial tunnel anterior to the conoid ligament graft.
Again, the graft is cyclically loaded multiple times. While holding reduction and tension on the ligament, another 5.5 × 8-mm nonabsorbable radiolucent screw is placed in the lateral trapezoid tunnel anterior to the trapezoid ligament graft.
With both grafts secured, the no. 2 ultra-high-strength nonabsorbable suture is tied over the top of the clavicle, becoming the nonbiologic fixation for the reduced AC joint.
TECH FIG 4 • A. Anatomic reconstruction of the coracoclavicular ligaments. For conoid ligament reconstruction, a guide pin is placed in the clavicle 45 mm from the acromioclavicular joint in a posteromedial position. For trapezoid ligament reconstruction, a guide pin is placed 30 mm from the acromioclavicular joint centered on the clavicle. B. After confirming the positions of the pins, a 5.5-mm cannulated drill is used to drill the clavicle. Care should be taken to place the conoid tunnel as far posterior as possible without violating the posterior cortex during reaming.
TECH FIG 5 • The free ends of the graft are crossed and passed through the clavicle. The graft is pulled back and forth through the tunnels and cyclic loading is placed on the graft. A short tail is left superior to the clavicle for the conoid ligament while the remainder of the graft exits the trapezoid tunnel, with one end left longer than the other. A 5.5 × 8-mm nonabsorbable radiolucent screw is used for interference fixation of the graft to the conoid tunnel in the clavicle. Cyclic tension is again placed on the graft. While holding reduction and the graft under tension, another 5.5 × 8-mm nonabsorbable radiolucent screw is placed in the anterolateral trapezoid tunnel.
DISTAL CLAVICLE EXCISION VERSUS ACROMIOCLAVICULAR JOINT REPAIR
For acute injuries, we perform an AC joint repair.
The AC joint is exposed. Simple or figure 8 sutures using a no. 0 nonabsorbable suture are used to repair the AC joint capsule and ligaments primarily.
The posterior and superior ligaments are key in preventing posterior displacement of the clavicle.
The repair can be augmented by using the limbs of the graft used for the coracoclavicular ligament repair.
The short limb of the graft exiting the medial tunnel is folded laterally and sewn to the base of the graft exiting the trapezoid tunnel in series (TECH FIG 6A).
The long limb exiting the lateral (trapezoid) tunnel is taken laterally and looped on top of the AC joint and used for augmentation of the AC joint capsule repair (TECH FIG 6B,C).
In chronic dislocations, two options exist.
One is to repair the AC joint as detailed above for acute AC joint injuries.
Alternatively, if arthrosis is a concern, a distal clavicle excision can be performed.
An oscillating osteotome is used to remove 1 cm of the distal clavicle.
The posterior cortical rim is beveled.
The deltotrapezial fascia is meticulously closed using interrupted nonabsorbable sutures, taking care to leave the knots on the posterior aspect of the trapezius.
A simple suture can be used to bury the knot if it is prominent.
Making clear full-thickness flaps during the approach and using tagging sutures allows for secure coverage of the grafts and clavicle.
TECH FIG 6 • A. The short limb of the graft representing the conoid ligament is folded laterally and sewn to the graft base representing the trapezoid ligament. B,C. The long limb representing the trapezoid ligament can be taken laterally and used to augment the acromioclavicular ligament fixation.
MODIFIED WEAVER-DUNN PROCEDURE
Diagnostic arthroscopy is done if concomitant injuries are suspected.9
An incision is made 1.5 cm from the AC joint starting at the posterior clavicle in a curvilinear fashion toward the coracoid along the lines of Langer.
The incision is sometimes angled because the key is to have full visualization of the AC joint laterally and coracoid process medially.
Superficial skin bleeders are controlled down to the fascia of the deltoid with a needle-tip Bovie.
Full-thickness flaps are made from the midline of the clavicle both posteriorly and anteriorly, skeletonizing the clavicle (TECH FIG 7).
Alternatively, a “hockey stick” incision can be made laterally from the acromion along the midportion of the clavicle, ending in a hockey stick fashion down toward the corocoid.
Periosteal flaps are elevated and a tagging suture can be placed at the medialmost aspect of the flap for accurate closure.
Biologic Fixation: Coracoacromial Ligament Transfer
The CA ligament is dissected out, especially laterally.
The CA ligament is detached from its footprint that extends posteriorly on the acromion (TECH FIG 8A).
TECH FIG 7 • Transfer of the acromial attachment of the coracoacromial (CA) ligament, the modified Weaver-Dunn procedure. Full-thickness flaps are made from the midline of the clavicle both posteriorly and anteriorly, skeletonizing the clavicle. Periosteal flaps are elevated and a tagging suture can be placed at the medialmost aspect of the flap for accurate closure. A small portion of the anterior deltoid is reflected from the anterior acromion to expose the CA ligament. (Adapted from Galatz LM, Williams GR Jr. Acromioclavicular joint injuries. In: Bucholz RW, Heckman JD, Court-Brown C, eds. Rockwood and Green's Fractures in Adults, vol 2. Philadelphia: Lippincott Williams & Wilkins, 2006:1354.)
Two heavy nonabsorbable sutures are placed at the end of the ligament using a whipstitch.
The CA ligament is held directly superiorly and the corresponding area is marked on the clavicle.
This marks the amount of clavicle that needs to be resected to allow easy passage of the CA ligament without sharp turns.
If adequate arthroscopic resection has not already been performed, an oscillating saw is used to make an oblique cut on the clavicle, leaving more bone superiorly rather than inferiorly, at the level of the previously marked site.
An intramedullary pocket is curetted inside the clavicle for the CA.
The AC intra-articular disc is resected, leaving the AC ligaments undisturbed.
A 2.0-mm drill is used to make two drill holes in a cruciate fashion (lateral clavicle anteriorly, medial clavicle posteriorly) 20 mm medial to the distal cut end of the clavicle (TECH FIG 8B).
A wire-loop is used to pass each limb of the CA ligament suture through the end of the clavicle and out the drill hole made superiorly.
For augmentation of CA ligament transfer, a 3.5-mm drill hole is made into the clavicle medial to the previously made drill holes for the CA ligament.
TECH FIG 8 • A. The ligament is released from the acromion and sutures are placed in the end. B. After a distal clavicle resection, two 2-mm unicortical drill holes are placed in the posterosuperior surface of the distal clavicle, exiting through the intramedullary canal. (Adapted from Galatz LM, Williams GR Jr. Acromioclavicular joint injuries. In: Bucholz RW, Heckman JD, Court-Brown C, eds. Rockwood and Green's Fractures in Adults, vol 2. Philadelphia: Lippincott Williams & Wilkins, 2006:1354.)
For nonbiologic augmentation, a suture cord is constructed.
The surgeon takes three no. 1 absorbable sutures clamped at both ends. One clamp is turned clockwise while holding the other end until the sutures are intertwined together for the entire length of the sutures.
This is done with two other sets of three sutures.
The three sets are intertwined counterclockwise in the same fashion, resulting in a cord of nine total sutures. The suture cord is passed around the coracoid and through the 3.5-mm drill hole in the clavicle.
For biologic augmentation an autograft or allograft can be used.
Reduction and Fixation
Upper displacement of the scapulohumeral complex and the use of a large point-of-reduction forceps placed on the coracoid process and the clavicle by the assistant are used to reduce the AC joint.
Slight overreduction during fixation is recommended.
After reduction is achieved, the surgeon pulls the suture limbs of the CA ligament reconstruction, exiting the bone tunnels, and ties them on the superior surface of the clavicle (TECH FIG 9).
The pocket for the CA ligament must be long enough so that after anatomic reduction, the graft is nice and taut.
If the suture cord was used, the suture cord that was passed around the coracoid and through the clavicle is tied.
The surgeon should attempt to place the knot in the least prominent area.
The ends of the suture cord are unraveled and each individual suture limb is tied to prevent unraveling of the cable.
Finally, all free suture ends are cut.
If ligament augmentation was used, the ligament is wrapped in a figure 8 fashion and sutured to itself using heavy nonabsorbable sutures.
Closure is the same as the ACCR technique (see TechFig 6C).
TECH FIG 9 • Using a curette, a pocket is made inside the clavicle for the coracoacromial (CA) ligament. The CA ligament is transferred to the intramedullary canal. The sutures are placed through the drill holes and tied over the top of the clavicle. This pocket has to be large enough so that after reduction of the joint, the CA ligament can be pulled inside without any impediment. If this is done correctly, the ligament should be taut and not overstuffed inside the pocket. (Adapted from Galatz LM, Williams GR Jr. Acromioclavicular joint injuries. In: Bucholz RW, Heckman JD, Court-Brown C, eds. Rockwood and Green's Fractures in Adults, vol 2. Philadelphia: Lippincott Williams & Wilkins, 2006:1354.)
ARTHROSCOPIC STABILIZATION
The patient is placed in a beach-chair position. Draping is similar to the open procedures, with wide exposure and the arm draped free.
Establishing Portals
A standard posterior portal is made, followed by two anterior portals (TECH FIG 10).
An anterosuperior portal is made using an outside-in technique, using a spinal needle to confirm positioning.
Débridement of the rotator interval is done until the tip of the coracoid is visualized.
Release of the superior glenohumeral ligament and partial release of the middle glenohumeral ligament may be required for adequate exposure.
A 7-mm partially threaded cannula is used for the anterosuperior portal.
An anteroinferior portal is made near the tip of the coracoid, again with the outside-in technique, using a spinal needle to confirm positioning and ensuring that the base of the coracoid can be reached using this portal. An 8.25-mm twist-in cannula is inserted for this portal.
A 70-degree scope may improve visualization of the coracoid base.
If the 30-degree arthroscope is used, the arthroscope position is changed to the anterosuperior portal.
The coracoid base is exposed using mechanical shavers and radiofrequency devices.
Any bursa or periosteum is stripped to obtain a full view of the coracoid base.
TECH FIG 10 • Three portals are used for arthroscopic repair— the standard posterior portal, an anterosuperior portal, and an anteroinferior portal.
Drilling
The assembled “Adapteur Drill Guide C-Ring with the Coracoid Drill Stop and Graduated Guide Pin Sleeve” (Arthrex, Inc., Naples, FL) is inserted through the anteroinferior portal (TECH FIG 11A).
With the drill stop placed at the base of the coracoid (as close to the scapula as possible), the corresponding area is marked on the superior aspect of the clavicle for the guide pin sleeve.
This area should be centered on the clavicle and approximately 25 mm from the AC joint.
A 1.5-cm incision is made over the clavicle in the lines of Langer, and the surgeon dissects down through the deltopectoral fascia.
TECH FIG 11 • A. Adapteur Drill Guide C-Ring (Arthrex Inc., Naples, FL). B,C. Using the Adapteur Drill Guide C-Ring with the Coracoid Drill Stop under direct visualization, a guide pin is placed through the clavicle and coracoid, engaging the drill stop. The pin should be centered on the clavicle and the coracoid and should exit the coracoid base as close to the scapula as possible. D,E. Once positioning has been confirmed, a 4.0-mm drill is used to drill the clavicle and coracoid. The surgeon should take care to stop at the drill stop and not advance past the coracoid base. (A,B,D: Courtesy of Arthrex, Inc.)
TECH FIG 12 • A. The power drill is detached and the cannulated drill is used as a portal to pass an 18-inch Nitinol suture passing wire. B. A grasper is used to hold the Nitinol suture while the drill bit is removed. The limb of the Nitinol passing wire is brought out of the anteroinferior portal, leaving the loop superior to the clavicle. C. The Nitinol suture passing wire is used to deliver the white traction sutures through the clavicle and coracoid and out of the anteroinferior portal. D,E. While holding the blue TightRope suture tails, pulling on one of the white suture tails flips the oblong button to a vertical position, allowing passage of the TightRope through the clavicle and coracoid. F. Once past, independent pulling on the white sutures flips the oblong button back to a horizontal position, anchoring it underneath the coracoid. (A,D: Courtesy of Arthrex, Inc.)
Under direct visualization using the arthroscope, the surgeon places a 2.4-mm guide pin through the drill tip guide, clavicle, and coracoid until the drill stop is engaged (TECH FIG 11B,C).
It is important to place the guide pin centered in the base of the coracoid.
A 4.0-mm cannulated drill is used to drill the clavicle and coracoid while the drill stop prevents migration of the guide pin. The surgeon should always use the arthroscope for direct visualization and avoid drilling beyond the coracoid base (TECH FIG 11D,E).
Suture Passage and Tying
The power drill is detached, leaving the cannulated drill in place.
An 18-inch Nitinol suture passing wire is passed down through the cannulated drill and the tip is grasped with the arthroscopic grasper (TECH FIG 12A,B).
The drill can now be removed.
Using the Nitinol passing wire, the two white traction sutures of the oblong button of the TightRope System are passed through the clavicle, the coracoid, and the anteroinferior portal (TECH FIG 12C).
TECH FIG 13 • Placing the arthroscope into the subacromial space via the posterior portal helps to directly visualize the reduction. After reduction of the clavicle, sequential pulling on the blue TightRope suture tails delivers the round button down to the superior clavicle, holding the reduction firmly. The blue sutures are tied securely. (Courtesy of Arthrex, Inc.)
The blue TightRope suture tails of the round button are held firmly with one hand. The surgeon pulls on the white suture tails attached to the oblong button. This flips the oblong button to a vertical position and allows passage through the drill holes (TECH FIG 12D,E).
The oblong button is pulled through the clavicle and coracoid.
Once passed, differential pulling on the white sutures flips the button to a horizontal position, preventing it from retracting through the drill holes (TECH FIG 12F).
Clavicle Reduction
The surgeon pulls on the blue suture tails to advance the round button down to the clavicle. The sutures are tied over the top of the TightRope, making a surgeon's knot and two reverse half-hitches.
Leaving the tails long helps the knot to lie flat (TECH FIG 13).
All wounds are irrigated and closed.
POSTOPERATIVE CARE
Postoperative support with a Lerman Shoulder Orthosis (DJO Inc., Vista, CA) or a Gunslinger Shoulder Orthosis (Hanger Prosthetics & Orthotics, Inc., Bethesda, MD) is used for 6 to 8 weeks. These braces are recommended to counter the pull on the shoulder complex by gravity.
For the first 6 to 8 weeks, the brace may be removed for grooming and supine gentle passive range of motion only.
Active and passive range-of-motion exercises are started at 8 weeks after surgery.
If painless range of motion is obtained, strength training is started at 12 weeks.
OUTCOMES
Anatomic coracoclavicular reconstruction: unpublished data from an ongoing study (level IV evidence) at our institution between 2002 and 2006;
427 cases of AC joint dislocations with a surgical rate of 3.7%
16 cases (two revisions)
Mean postoperative months: 28.9
One failure (noncompliant)
To date, preliminary results show a mean Single Assessment Numeric Evaluation (SANE) score of 98.4/100. Other outcome measures, including American Shoulder and Elbow Surgeons (ASES), Rowe, and Constant scores, are 94.1, 91, and 96, respectively. Patients have a pain rating of less than 1/10 with horizontal adduction and forward elevation and when a posterior force is directed at the AC joint. Postoperative radiographs show that the mean difference in the coracoclavicular distance is 2.1 mm compared to the contralateral side.
Weaver-Dunn
Outcomes are difficult to compare due to the variations in the Weaver-Dunn method used and the makeup of the type of patients and severity of injury within study groups.
Rauschning et al10 reported 12 acute and 5 chronic type III AC joint injuries treated by the Weaver-Dunn procedure. At follow-up 1 to 5 years after the operation, all patients had stable and painless shoulders with resumption of full activities and functionally excellent results (level IV evidence).
Tienen et al15 presented 21 patients with Rockwood type V AC joint dislocations who underwent a modified WeaverDunn procedure with clavicle reduction and AC joint fixation using absorbable braided sutures. At a mean follow-up of 35.7 months, 18 patients had returned to their sports without pain within 2.5 months after operation; the average Constant score at last follow-up was 97. Radiographs taken at this time showed residual subluxation in two patients and, in one patient, redislocation of the joint that occurred because of infection (level IV evidence).
When chronic and acute repairs of type III AC joint injuries were studied, patients with early repair were significantly better after 3 months. In a study by Weinstein et al,17 26 of 27 (96%) patients with early repairs and 13 of 17 (77%) patients with late reconstructions achieved satisfactory results with an average 4-year follow-up (level IV evidence).
Arthroscopic reconstruction with the TightRope System: preliminary results of an ongoing study:
29 patients with a mean age of 31 years and 6-month follow-up
Mean Constant score 91.1
Mean ASES score 96.66
Return to sports mean of 12 weeks
Complications: one hardware failure with revision using TightRope and one patient with transient adhesive capsulitis
COMPLICATIONS
Loss of reduction
Excessive distal clavicle resection
Osteolysis due to nonbiologic fixation material
Coracoid fracture
Infection
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