HAGL Lesions

IGHL Complex

• Anterior Band: The primary restraint to anterior translation in abduction and external rotation (ABER). Requires restoration.
• Posterior Band: Restraint to posterior translation in flexion/internal rotation.
• Axillary Pouch: The hammock between the bands.

The IGHL inserts onto the humeral neck, just below the articular surface.

This insertion is the "weak link" in HAGL lesions.

Humeral Insertion Anatomy

• Location: Anatomical neck, approximately 1-2 cm from articular margin.
• Width: The IGHL insertion spans 2-3 cm along the humeral neck.
• Blood Supply: Branches of anterior circumflex humeral artery.
• Surgical Relevance: Anchors must be placed at the anatomical footprint for restoration.

Understanding this anatomy is critical for proper anchor placement during repair.

Mechanism of Injury

• Hyper-abduction and External Rotation.
• Similar mechanism to Bankart, but the failure point is humeral.
• Studies suggest HAGL may occur when the rotator cuff is intact (stiff humerus) or with concurrent subscapularis strain.
• Biomechanical Consequence: Removes the anterior check-rein. The head translates anteriorly without resistance.

The axillary pouch loses its tension, failing to cradle the head in abduction.

Biomechanical Consequences

• Hammock Failure: The IGHL functions as a hammock supporting the humeral head in ABER. HAGL removes this support.
• Stability Ratio: The force required to cause dislocation is reduced by up to 50%.
• Associated Injuries: Often occurs with subscapularis strain due to shared anterior structures.
• Healing Potential: Unlike Bankart, HAGL lesions have limited spontaneous healing due to retraction and synovial environment.

Spectrum of Capsular Failure

Understanding the continuum is essential for diagnosis:

• Bankart: Glenoid-side labral avulsion.
• ALPSA: Medialized glenoid-side failure with intact periosteum.
• HAGL: Humeral-side avulsion of the ligament proper.
• Floating IGHL: Bipolar failure - both ends detached (most severe).

Proper identification of the specific failure pattern directs appropriate surgical management.

West Point Classification (Bui-Mansfield)

• Type A: Anterior HAGL (93%) - Avulsion of anterior band from humeral neck.
• Type B: Posterior HAGL (7%) - Avulsion of posterior band (rare).
• Type C: Floating AIGHL (Bipolar - Glenoid and Humeral) - Both ends detached.
• Bony HAGL (BHAGL): Any of the above with a bone fragment from the humerus (20%).

BHAGL is often easier to heal (bone-to-bone) if fixed.

The floating type represents a devastating loss of all inferior restraints.

HAGL Variants

• Anterior HAGL: Most common (93%). Affects anterior band of IGHL.
• Posterior HAGL (PHAGL): Rare (7%). Associated with posterior instability.
• Bony HAGL (BHAGL): Avulsion fracture from humeral neck. Visible on X-ray.
• Floating IGHL: Complete detachment from both glenoid and humerus.
• Combined HAGL-Bankart: Dual pathology - both sides affected.

Prognostic Implications

MRI Signs

• J Sign: Retraction of the IGHL.
• Double Axillary Pouch: Can mimic a double pouch if fluid extravasates.
• Extravasation: Contrast (Arthrogram) leaking laterally down the humerus (not typical, usually medial leak for Bankart - wait, HAGL leaks medially too? No, HAGL leaks from humeral side, so extravasation extends laterally/inferiorly along the shaft).
• Edema: Bone edema at the humeral neck (acute).

Always evaluate the integrity of the capsule on the humeral side.

The "Fake" HAGL

• The IGHL is lax in adduction.
• Folds can look like tears.
• Look for fluid extending below the teres minor or frank detachment.
• MR Arthrography (MRA) significantly increases sensitivity.

A high index of suspicion is required to differentiate artifact from pathology.

Decision Making

• Non-Operative: Low demand, elderly. (Immobilization in internal rotation? No, ER brace logic applies to Bankart, unlikely to help HAGL retraction).
• Operative: Young, Athletes, Recurrent Instability.
• Choice of Approach:
  • Open: Gold Standard. Associated Subscap tear. Easier to find and fix.
  • Arthroscopic: Technically difficult. Needs 70-degree scope and accessory portals (5 o'clock).

The choice depends largely on surgeon experience and presence of subscapularis pathology.

Timing

• Acute repair (less than 3 weeks) allows mobilization of tissue.
• Chronic HAGL may be scarred and retracted, making arthroscopic repair impossible.

Chronic cases often require open release of the capsule to mobilize it.

Open Repair (L-shaped Incision)

• Approach: Deltopectoral.
• Subscapularis: L-shaped tenotomy or Takedown (lower half) to access the deep capsule.
• Identification: Humerus is externally rotated to reveal the avulsed ligament.
• Fixation: Suture anchors (double loaded) placed in the humeral neck.
• Closure: Repair Subscapularis robustly.
• Pros: Visualization, protect Axillary nerve.
• Cons: Subscapularis morbidity.

The L-shaped tenotomy provides excellent exposure of the inferior pouch.

Arthroscopic Repair

• Portals: Standard post/ant. Accessory low anterior (5 o'clock) or trans-subscapularis portal.
• Technique:
  1. View from Anterior portal (or high anterolateral).
  2. Prepare bone bed on humerus (difficult angle).
  3. Pass sutures through ligament first (outside-in or penetrator).
  4. Fix to humerus.
• Risks: Axillary nerve (at 6 o'clock) is dangerously close to the 5 o'clock portal.

Visualization is key; switch portals frequently.