Arthroscopic Repair of a Glenoid Avulsion of the Glenohumeral Ligament

Abstract

Injury to the glenohumeral capsulolabral complex is the critical lesion in anterior shoulder instability. Various injury patterns have been described including the classic Bankart lesion, the bony Bankart lesion, and humeral avulsion of the glenohumeral ligament. A rare injury variant is a glenoid avulsion of the glenohumeral ligament (GAGL lesion). Careful patient setup and surgical technique are required to identify and arthroscopically repair these lesions. We describe a suture anchor–based arthroscopic GAGL repair performed with the patient in the lateral decubitus position through standard anterior and posterior portals and an accessory posterolateral 7-o'clock portal.

Traumatic instability is the most common shoulder injury in the young active population.¹ A variety of injury patterns to the glenohumeral capsulolabral complex have been described; these are classified based on the location of injury. The most common injury pattern is the Bankart lesion, or a complete detachment of the capsulolabral complex from the anterior glenoid.² The Bankart lesion may also present as a bony anterior glenoid avulsion.³ Less common patterns include an avulsion of the inferior glenohumeral ligament (IGHL) from its humeral attachment (HAGL) or intracapsular tears.³

The most recently described injury pattern is an avulsion of the IGHL from the glenoid with an intact labrum, referred to as a “glenoid avulsion of the glenohumeral ligament” (GAGL) (Fig 1).⁴ The indications for performing arthroscopic GAGL repair include a clinical history of traumatic anterior shoulder dislocation with a glenoid avulsion of the IGHL present at the time of surgery, with normal humeral and glenoid bone stock. Contraindications include glenoid and humeral bony deficiency, as well as capsular tissue that is of insufficient quality to achieve successful repair (Table 1). We present an arthroscopic technique for reliable identification and anatomic fixation of GAGL lesions. Table 2 lists the advantages and disadvantages of this technique.

Fig 1.

Magnetic resonance appearance of a glenoid avulsion of the glenohumeral ligament. A T2-weighted magnetic resonance arthrogram in the axial (A) and coronal (B) planes is shown. The anteroinferior glenoid labrum is normal in appearance. A patulous anteroinferior capsule is seen on both the axial (A) and coronal (B) views. The leading edge of the avulsed inferior glenohumeral ligament can be seen on both views (asterisks) and correlates with the intraoperative appearance of the injury.

Table 1.

Indications and Contraindications

Indications

Clinical history of traumatic anterior shoulder dislocation

Glenoid avulsion of inferior glenohumeral ligament seen at time of arthroscopy

Normal glenoid and humeral bone stock

Contraindications

Glenoid bone loss >20%

Engaging Hill-Sachs lesion

Poor-quality capsular tissue

Table 2.

Advantages and Disadvantages

Advantages

An arthroscopic procedure allows a faster recovery.

Arthroscopy in the lateral decubitus position allows excellent visualization and instrumentation of the inferior capsule and glenoid.

Any concomitant intra-articular pathology can easily be visualized and addressed.

If the capsular injury extends posterior to the 6-o'clock position, arthroscopic repair of the posterior capsulolabral complex is much simpler than an open repair.

Disadvantages

Advanced arthroscopic skills and a high index of suspicion are required.

The approach is less extensile than a formal open approach if more extensive capsular injury or a HAGL lesion is encountered.

HAGL, humeral avulsion of glenohumeral ligament.

Surgical Technique

Patient Positioning

After induction of general anesthesia and placement of an interscalene nerve block, the patient is placed in the lateral decubitus position with the use of a beanbag (Olympic Vac-Pac; Natus, Pleasanton, CA). The patient is leaned 15° to 20° posteriorly to place the glenoid parallel to the floor. The operative arm is placed in balanced suspension using the Arthrex 3-point distraction system (AR-1600M; Arthrex, Naples, FL) and STaR Sleeve (AR-1606; Arthrex). The lateral traction beam should be extended until it is directly above the patient's axilla to ensure sufficient lateral humeral translation. The longitudinal traction beam (AR-1601; Arthrex) is rotated 20° away from the patient. Ten pounds of longitudinal traction is applied. The arm is strapped in neutral rotation, and 10 lb of lateral distraction is applied. Finally, a bolster is placed in the axilla to provide additional visualization of the inferior structures and axillary recess.

Portal Placement and Diagnostic Arthroscopy

A standard posterior portal is created approximately 2 cm inferior to the posterolateral corner of the acromion. This should be 1 to 2 cm lateral to the posterior soft spot to allow an adequate trajectory for posterior glenoid anchor placement if necessary. An anterior portal is created through the center of the rotator interval, and a 5.5-mm smooth cannula (AR-6532; Arthrex) is placed through a small skin incision. The arthroscope is switched to the anterior portal, and diagnostic arthroscopy is completed from both views.

While the surgeon is viewing from the anterior portal, an 18-gauge spinal needle is used to identify the ideal location for a 7-o'clock portal. This is typically 4 cm lateral to the posterolateral corner of the acromion. The spinal needle trajectory is nearly perpendicular to the floor, aiming at the coracoid and hugging the humeral head to increase the distance between the portal and the axillary nerve. A small skin incision is created, and a Wissinger rod is placed along the same trajectory as the spinal needle. Sequential dilation is performed with an obturator (AR-6531; Arthrex), and a clear 8.25-mm × 7-cm cannula (AR-6530; Arthrex) is placed over the rod.

Identification of Injury to IGHL

The camera is replaced in the posterior glenohumeral portal (Video 1). Careful inspection of the anteroinferior quadrant will show a normal-appearing anteroinferior labrum (Fig 2A). The leading edge of the torn IGHL can be seen retracted toward its humeral attachment (Fig 2B). The subscapularis muscle fibers can be seen through the resultant capsular defect. A full understanding of the injury pattern requires manipulation of the injured capsule. A KingFisher suture retriever (AR-13970SR; Arthrex) is placed through the anterior cannula and is used to mobilize the torn capsular edge back to its donor site on the glenoid. The capsular tissue should be pulled in a proximal and medial direction until adequate tension is restored in the IGHL.

Fig 2.

Arthroscopic appearance of a glenoid avulsion of the glenohumeral ligament. (A) Viewing from the posterior portal with the patient in the lateral decubitus position and the arm in traction, one can see that the anteroinferior labrum is firmly attached to the glenoid rim with no fraying or hemorrhage. (B) A patulous anteroinferior capsule is seen, with the leading edge of the avulsed inferior glenohumeral ligament retracted laterally and distally from its origin on the glenoid. The typically taut anterior band of the inferior glenohumeral ligament is not visualized.

Temporary Reduction of IGHL

GAGL repair is greatly facilitated by placement of a temporary reduction stitch at the proximal edge of the torn IGHL (Fig 3). A Spectrum device (C6350; ConMed, Largo, FL) is placed through the 7-o'clock portal. A 45° suture hook (C6360 or C6361; ConMed) is used, with the hook directed in the opposite direction to the operative arm (a 45° right hook was used for the left shoulder repair shown in Video 1). A No. 2 FiberWire (AR-7233; Arthrex) is shuttled through the proximal edge of the torn IGHL and attached to the intact glenoid labrum to maintain the reduction during subsequent repair.

Fig 3.

Reduction of the capsule back to the glenoid (Glen). Viewing from the anterior portal with the patient in the lateral decubitus position and the arm in traction, one can visualize the entire anteroinferior quadrant. (A) A grasper introduced from the anterior portal is used to grasp the torn anterior band of the inferior glenohumeral ligament (AIGHL). The capsule is pulled in a superior direction until appropriate tension is restored in the inferior glenohumeral ligament. (B) To facilitate subsequent anchor repair, the capsule is fixed to the labrum with a single high–tensile strength suture, maintaining an anatomic reduction during the rest of the procedure. This is achieved by introducing a Spectrum suture hook through the 7-o'clock portal, piercing the inferior glenohumeral ligament, and then piercing the labrum in a separate bite. The anterior portal is used for suture shuttling.

Anchor-Based Repair of IGHL to Glenoid Rim

The anteroinferior capsule is gently rasped (AR-1312; Arthrex) to promote a healing response (Fig 4, Fig 5). All suture anchors are placed percutaneously through the subscapularis using a percutaneous insertion kit (AR-1934PI-30; Arthrex). A double-loaded 3.0-mm BioComposite SutureTak anchor (AR-1934BCF-2; Arthrex) is placed at the 6-o'clock position on the glenoid. Two simple stitches are placed through the most inferior portion of the torn IGHL and then the native, uninjured labrum using the 45° Spectrum through the 7-o'clock portal. By sewing from the back, an excellent inferior-to-superior shift is obtained. The anterior cannula is used for suture management. The stitches are sequentially tied with an arthroscopic surgeon's knot through the 7-o'clock portal. Two additional anchors are placed using the same percutaneous technique, moving proximally along the glenoid every 6 to 7 mm. For the final, most anterior anchor, suture passage should be performed through the anterior portal, with a 45° Spectrum hook curved in the same direction as the operative extremity (Fig 3B).

Fig 4.

Anchor-based fixation in the inferior capsular recess. (A) Anchor repair should begin at the 6-o'clock position. The first anchor is inserted percutaneously through the subscapularis. (B) A Spectrum suture hook is passed through the 7-o'clock portal and used to perforate both the capsule and the labrum. Care should be taken to shift the capsule from posterior to anterior, as well as medial to lateral. (C) A double-loaded anchor allows for 2 simple stitches to be placed, creating a robust capsulolabral “bumper.” Two double-loaded anchors are used to re-create inferior capsular tension.

Fig 5.

Anchor-based fixation in the anteroinferior quadrant. The repair is completed with a third anchor in the anteroinferior quadrant. (A) The anchor is inserted percutaneously through the subscapularis. (B) The Spectrum suture hook is inserted through the anterior portal while the surgeon is viewing through the posterior portal. A “pinch-tuck” technique is used to capture the anterior capsule and then the anteroinferior labrum. The surgeon places 2 simple stitches in this fashion, completing the repair of the glenoid avulsion of the glenohumeral ligament. (C) A panoramic view of the repair can be obtained by placing the camera in the anterior portal.

Side-to-Side Repair of Inferior Capsule to Mid-Anterior Capsule

For the IGHL to retract distally, there is necessarily a disruption in the anterior capsule perpendicular to the face of the glenoid. This marks the superior border of the zone of injury. Once the IGHL has been anatomically reduced and fixed to the glenoid with the use of 3 double-loaded suture anchors, the perpendicular limb of the capsular split is repaired side to side using a 45° curved Spectrum hook through the anterior portal. PDS suture (Ethicon, Somerville, NJ) or FiberWire suture can be used according to surgeon preference. The stitch is then tied with a sliding Duncan loop knot and directed away from the articular surface (Fig 3B).

Postoperative Rehabilitation

Patients follow our standard anterior instability protocol after undergoing fixation of a GAGL lesion. The repair is protected by use of a sling and abduction pillow for 4 weeks. Physical therapy is initiated 1 week after surgery, focusing on restoration of passive and active-assisted range of motion. Motion is restricted to 90° of forward flexion and 20° of external rotation at the side for 4 weeks. Once the sling is discontinued at 4 weeks, range of motion is progressed to 160° of forward flexion and 45° of external rotation at the side. Isometrics, scapular stabilization, and light-band strengthening are begun and continue until 8 weeks. From 8 to 12 weeks, strengthening with light weights (<5 lb) is started and range-of-motion restrictions are removed. At 3 months, advanced strengthening and sport-specific rehabilitation are initiated. Return to sports is typically achieved around 6 months.

Discussion

Recognition of the GAGL lesion is the critical and most difficult portion of the described procedure. We believe that careful positioning in the lateral decubitus position greatly facilitates visualization of the injured IGHL. In addition, manipulation of the torn capsule is required to understand the extent of the injury. It is now well documented that up to 25% of patients with anterior instability do not have a classic Bankart lesion, and careful examination of the capsular complex should be performed in all patients with a history of anterior instability and a normal-appearing labrum.³

The 2 essential technical pearls for successful GAGL repair are the use of the 7-o'clock portal for suture passage and percutaneous placement of suture anchors through the subscapularis (Table 3). The 7-o'clock portal is a safe portal and is typically more than 35 mm from the axillary nerve.⁵ Pearls for placement of this portal have been previously described and should be closely followed to reduce the risk of neurovascular injury.⁵ Placement of percutaneous anchors through the subscapularis has been shown to reduce the risk of glenoid cortical breach,⁶ although a difference in pullout strength between the 2 techniques was not shown. Regarding potential pitfalls, the use of low percutaneous portals does pose a risk of neurovascular injury, with the axillary artery and nerve and the cephalic vein running within 15 mm.⁷ Therefore the use of blunt percutaneous insertion devices is an important step toward safe insertion of anchors in the lowest portion of the glenoid.

Table 3.

Pearls and Pitfalls

Pearls

The 7-o'clock portal is essential for reaching the inferior glenoid and reducing the GAGL lesion.

Percutaneous placement of suture anchors through the subscapularis optimizes anchor positioning and reduces the risk of a glenoid cortical breach or “skiving.”

Every attempt should be made to optimize patient positioning because visualization and correct portal placement ultimately depend on positioning.

A temporary reduction stitch holding appropriate tension in the IGHL facilitates anchor repair of the GAGL lesion.

Pitfalls

Failure to identify the lesion is the primary pitfall. Suspicion for a capsular injury should be heightened by the clinical history of instability yet a normal labral appearance.

Injury to the axillary nerve is possible if a deep bite is taken with the suture hook in the anteroinferior quadrant.

Failure to shift the IGHL in a proximal direction will not restore adequate tension in the ligament and may lead to a higher risk of recurrence.

Injury to the cephalic vein is possible with low percutaneous subscapularis anchor insertion. Incisions should be made through the skin only, and percutaneous cannulated anchor systems can minimize the risk of injury to the vein.

GAGL, glenoid avulsion of glenohumeral ligament; IGHL, inferior glenohumeral ligament.

The only prior description of GAGL repair used soft-tissue fixation with PDS sutures through the IGHL and intact labrum.⁴ Use of the glenoid as a “suture anchor” affords similar loads to failure to anchor fixation in cadaveric models; however, increased displacement with cyclic loading is seen with soft-tissue fixation.⁸ In addition, microscopic injury to the labrum during episodes of recurrent anterior instability may further compromise fixation strength in vivo. For these reasons, we prefer an anchor-based GAGL repair.

In summary, GAGL lesions are a rare cause of anterior instability that can be safely and efficiently repaired by arthroscopic techniques. Once secure fixation is achieved, patients can be rehabilitated according to the standard protocols for anterior instability.

Supplementary Data

Video 1

Arthroscopic repair of a glenoid avulsion of the glenohumeral ligament (GAGL). Axial and coronal magnetic resonance images show a patulous inferior capsule but a normal glenoid labrum. Glenohumeral arthroscopy through a posterior portal shows that the anteroinferior labrum has a normal appearance. In the anteroinferior quadrant, the avulsed anterior band of the inferior glenohumeral ligament (IGHL) is seen retracted laterally and distally. A KingFisher device is introduced through the anterior portal created in the center of the rotator interval. The avulsed capsule is mobilized proximally until normal tension is restored in the anterior band of the IGHL. We then place a temporary reduction stitch to hold the capsule in an anatomic position during suture anchor repair using a 45° Spectrum to the right through the 7-o'clock portal. The percutaneous spear for a 3-mm double-loaded BioComposite SutureTak is placed through the subscapularis tendon, and an anchor is placed at the 6-o'clock position. The anterior portal is used for suture management. The same Spectrum is used through the 7-o'clock portal, and a simple stitch is placed through the IGHL and the intact labrum. The capsular tissue should be shifted in an anterior and superior direction. This is achieved by piercing the tissue more posteriorly than the location of the anchor and is the primary advantage of using the 7-o'clock portal. The process is repeated with the TigerWire suture (Arthrex). A second anchor is placed approximately 7 mm more anteriorly on the glenoid face. The Spectrum device should still be passed through the 7-o'clock portal, and 2 simple stitches are placed. A third and final anchor is placed near the 9-o'clock position in this left shoulder. At this point, it is easier to use a 45° Spectrum to the left through the anterior portal. The 7-o'clock portal is used for suture management. This 3-anchor repair anatomically restores the anterior band of the IGHL and eliminates the capsular redundancy seen on initial diagnostic arthroscopy. For the IGHL to retract distally, there must be a transverse capsular disruption, which is seen overlying the subscapularis. This can be repaired in a side-to-side fashion with a No. 0 PDS suture placed through the anterior portal.