This article is more than 5 years old. Information may no longer be current.
Open technique offers safe, effective repair of HAGL lesions
Click Here to Manage Email Alerts
While not as common as avulsion of the anterior capsulolabral complex, humeral avulsion of the glenohumeral ligament has been prospectively identified in as many as 9% of shoulder instability patients. Other reports suggest the incidence may be as high as 21%.
The humeral avulsion of the glenohumeral ligament (HAGL) lesion represents a spectrum of pathologies, but involves disruption of the inferior glenohumeral ligament (IGHL) off its humeral insertion. Sixty-two percent of patients with an HAGL lesion present with other pathologies including Bankart lesions (anterior capsulolabral avulsion), Hill-Sachs lesions (cortical depression in the posterior superior humeral head) or rotator cuff tears. Instability in the absence of a Bankart lesion should raise suspicion for a possible HAGL injury. Failure to recognize the presence of a HAGL lesion in shoulder instability may lead to unsuccessful treatment outcomes due to failed glenohumeral stabilization. Furthermore, there is increasing recognition that overhead throwing may be associated with HAGL lesions from excessive external rotation or “hyperrotation” during the late cocking and early acceleration phase of throwing.
The inferior glenohumeral ligament is comprised of the anterior and posterior bands, as well as the interposed capsular tissue of the axillary pouch. This forms a hammock-like structure spanning from the anterior and posterior aspects of the inferior glenoid to the inferior humeral neck. The humeral insertion of the IGHL forms a “V” shape, which accommodates the humeral head in abduction. This structure provides most of the anterior stability with the arm in 90° of abduction. It attaches just below the articular surface of the humerus. HAGL lesions are typically thought to occur from acute trauma to the shoulder with the humerus in a position of hyperabduction and external rotation. This stresses the anterior-inferior capsuloligamentous structures and can lead to acute subluxation, luxation or dislocation. Therefore, anterior band lesions are much more commonly encountered (93% incidence) compared to the posterior band lesions (7%). In addition, overhead throwers may present with significant anterior shoulder pain without a history of instability from pathologic stretching and actual tearing of the anterior-inferior glenohumeral ligament either from the humeral attachment or within the substance of the capsule and ligament.
Diagnosis
Most patients are young with a history of a traumatic instability event. Some patients, however, may present without a history of acute trauma. Recent series demonstrated a high incidence in patients subjected to repetitive overhead activities. Such patients may have non-specific complaints such as pain or weakness without apprehension. Therefore, the possibility of a HAGL must be considered even in patients without a history of frank dislocation, especially if the position of abduction and external rotation is associated with persistent recurrence of the symptoms
The presence of a Bankart lesion does not exclude a HAGL lesion, so thorough radiologic and arthroscopic evaluation of the IGHL should be pursued, even if capsulolabral pathology has been identified. This is of utmost importance in the setting of revision cases for previous failed shoulder instability surgery.
Figure 1. This MRI was taken of the humeral avulsion of the glenohumeral ligament in a 27-year-old male patient.
Images: Romeo AR
Careful inspection of AP radiographs may reveal a bony avulsion or scalloping at the medial cortex of the humeral anatomic neck. While diagnosis may be suggested on plain radiographs, most (83%) lesions are soft-tissue injuries identified by MRI. On MRI, joint fluid or contrast can be seen extravasating from the axillary pouch. The normal U-shape of the axillary pouch will be distorted and is often visualized as a J-shape representing disruption of the IGHL/capsule complex (Figure 1).
A lack of correlation of MRI and arthroscopic findings has led to questions regarding the accuracy of MRI in identifying classic HAGL lesions. Melvin and colleagues reported four patients with MRI diagnosis of HAGL lesions that, upon arthroscopic evaluation, demonstrated defects in the capsule without avulsion of the anterior-inferior ligament, which may clinically represent a “HAGL-equivalent” but not truly a disruption from the humeral attachment. This capsular defect simulated the MRI appearance of a HAGL. Other authors have suggested that HAGL lesions may heal. These authors demonstrated that 67% of patients with HAGL lesions identified on an MRI performed an average of 7 days after injury resolved on MRI arthrogram performed at an average of 30 days after injury. This may represent healing with scar tissue and not a true restoration of the capsule and ligament.
Multidetector CT (MDCT), a higher resolution form of conventional CT, has recently been shown to have a 100% sensitivity and specificity for preoperatively identifying a HAGL when correlated with arthroscopic findings. Further study is required to determine if these findings remain valid in other patient populations.
Figure 2a. The presence of the subscapularis muscle fibers marks the presence of an HAGL lesion, as the capsule has been pulled off its humeral attachment.
Figure 2b. The HAGL as viewed from the posterior arthroscopic portal, in a lateral position.
The gold standard for diagnosing a HAGL lesion is arthroscopy. Careful arthroscopic evaluation will reveal either anterior or posterior muscle exposure through the capsule, suggesting a capsular defect (Figures 2a and 2b). Most commonly, striations of the subscapularis can be visualized through a disrupted or attenuated capsule with the arthroscope in the posterior portal. A few capsular fibers may remain attached to the inferomedial aspect of the humeral head.
Surgical technique: Open
The following descriptions detail repairs on the more commonly encountered anterior HAGL lesion.
Figure 3a. The subscapularis is identified through the deltopectoral approach to the proximal humerus.
Figure 3b. An vertical incision through the inferior portion of the subscapularis just medial to the biceps tendon is made until it is just proximal to the anterior circumflex humeral artery. The horizontal portion of the incision starts at the superior portion of the vertical incision and is carried medially.
Figure 3c. The subscapularis is reflected off the capsule, and a tagging suture is passed to provide retraction.
Figure 3d. The interval between the subscapularis and the capsule is identified and carefully separated.
Relative indications for open repair include inability to repair arthroscopically, prior failed arthroscopic HAGL repair, revision stabilization procedures, HAGL with associated bone loss and/or bony avulsion, and concomitant proximal humerus fracture.
Figure 3e. Once the HAGL lesion has been identified, the humerus is externally rotated to bring the site of capsular avulsion into the operative field to allow anatomic anchor placement at the articular margin.
HAGL lesions can treated though an open, trans-subscapularis technique. The presence of the HAGL can be confirmed through arthroscopic evaluation prior to initiation of an open approach. In the beach chair position, a deltopectoral approach is used extending from the axillary fold towards the coracoid (Figure 3a). Scarring of the inferior portion of the subscapularis suggests an anterior HAGL lesion. An L-shaped incision through the subscapularis is used. The vertical incision is made first, starting 1.5 cm medial the lesser tuberosity extending from the midpoint of the subscapularis to a point just proximal to the anterior circumflex vessel. The incision is extended medially by approximately 2 cm to complete the “L” (Figure 3b). The subscapularis is gently separated from the capsule, revealing the anterior-inferior HAGL lesion. A tagging suture is placed through the reflected subscapularis to provide retraction and visualization (Figure 3c). The axillary nerve should be protected while the interval between the subscapularis and capsule is identified and separated. The inferior glenohumeral ligament is identified beneath the subscapularis (Figure 3d). The humerus may be externally rotated to provide optimal access to the site of capsular avulsion (Figure 3e). The proximal humeral insertion site is prepared with a burr or rasp. Suture anchors are used to secure the capsule back to the proximal humerus. Anatomic repair of the subscapularis can then be performed.
Bhatia and colleagues described a subscapularis-sparing approach through a 1-inch axillary deltopectoral approach for anterior HAGL lesions. After diagnostic arthroscopy confirms the HAGL lesion, the exposure exploits the interval just inferior to the lateral aspect of the subscapularis tendon and the pectoralis major tendon. Wide undermining of the skin around the incision is performed to allow this window to be shifted superiorly and laterally. After the pectoralis major tendon is retracted inferiorly, the subscapularis is bluntly dissected off the capsule and retracted superiorly exposing the lesion. The axillary nerve should be palpated medially, and all dissection should be performed lateral to this structure. The humeral avulsion site is then exposed and can be prepared and repaired with suture anchors.
For more information:
Disclosures: Bruce, Gupta and McCormick have no relevant financial disclosures. Bach receives financial or material support from Arthrex Inc., Linvatec, Smith & Nephew, CONMED Linvatec and Ossur; and receives royalties, financial or material support from SLACK Incorporated. Romeo receives royalties from is on the speakers bureau/does paid presentations for, is a paid consultant for and receives other financial or material support from Arthrex Inc.; receives research support as a PI from Arthrex Inc., DJO Surgical, Smith & Nephew, Ossur and Athletico.