Bankart Lesions: Soft vs. Bony, Diagnosis, and Treatment

What is the difference between bony Bankart and soft Bankart?

A Bankart lesion is an injury to the anterior-inferior aspect of the glenoid labrum, typically resulting from an anterior shoulder dislocation; a soft Bankart involves only the detachment of the labrum and surrounding soft tissues, while a bony Bankart includes a fracture of the glenoid bone itself, leading to bone loss and often greater instability.

Understanding Shoulder Instability and the Glenoid Labrum

The shoulder joint, or glenohumeral joint, is a highly mobile ball-and-socket joint, allowing for a wide range of motion. This mobility, however, comes at the cost of inherent stability. The "ball" is the head of the humerus (upper arm bone), and the "socket" is the shallow glenoid fossa of the scapula (shoulder blade). To enhance stability, the glenoid is encircled by the glenoid labrum, a fibrocartilaginous rim that deepens the socket and serves as an attachment point for the joint capsule and glenohumeral ligaments.

Shoulder instability occurs when the humeral head excessively translates on the glenoid, leading to subluxation (partial dislocation) or dislocation (complete separation). Anterior dislocations are the most common type, often resulting from a direct blow or fall on an outstretched arm that forces the humerus forward and downward.

What is a Bankart Lesion?

A Bankart lesion is a specific type of injury to the anterior-inferior portion of the glenoid labrum. It is the most common lesion associated with traumatic anterior shoulder dislocations and is considered a primary mechanical cause of recurrent anterior glenohumeral instability. When the humeral head dislocates anteriorly, it can peel off or tear the labrum from the front and bottom edge of the glenoid, disrupting the crucial capsuloligamentous structures that provide anterior stability.

Soft Bankart Lesion: The Classic Injury

A soft Bankart lesion, often referred to simply as a "Bankart lesion," involves the avulsion (tearing away) of the anterior-inferior glenoid labrum from the bone.

• Tissue Involved: This injury exclusively involves soft tissues, specifically the fibrocartilaginous labrum, the anterior joint capsule, and often the inferior glenohumeral ligament (IGHL) complex, which is a primary stabilizer against anterior translation.
• Mechanism: It typically occurs during a traumatic anterior shoulder dislocation where the humeral head is forced out of the socket, tearing the labrum off its bony attachment point.
• Pathology: The soft tissue structures are detached, but the underlying bone of the glenoid rim remains intact. This detachment compromises the "bumper" effect of the labrum and the integrity of the anterior capsular restraints, leading to recurrent instability.
• Clinical Significance: While it doesn't involve bone loss, the soft tissue detachment significantly compromises shoulder stability, making recurrent dislocations highly probable, especially in younger, active individuals.

Bony Bankart Lesion: A More Complex Challenge

A bony Bankart lesion is a more severe form of Bankart injury. It includes the soft tissue detachment characteristic of a soft Bankart, but critically, it also involves a fracture of the anterior-inferior glenoid rim.

• Tissue Involved: This injury involves both soft tissues (labrum, capsule, ligaments) and bone. A fragment of the glenoid bone is avulsed along with the attached labrum.
• Mechanism: Bony Bankart lesions typically result from more forceful anterior dislocations, where the humeral head not only tears the labrum but also impacts and shears off a piece of the glenoid bone.
• Pathology: The fracture leads to a loss of bone substance from the glenoid socket. This reduces the effective surface area of the glenoid, making the socket shallower and less able to contain the humeral head. The "bumper" effect is lost, and the overall stability of the joint is severely compromised.
• Clinical Significance: The presence of glenoid bone loss is a critical factor in shoulder instability. It significantly increases the risk of recurrent dislocations, even after surgical repair of the soft tissues. The bone defect can also allow for "engagement" of a Hill-Sachs lesion (an impaction fracture on the posterior-superior humeral head often occurring with anterior dislocations) during shoulder movements, further contributing to instability.

Key Differences Summarized

Diagnosis of Bankart Lesions

Diagnosis typically involves:

• Clinical History: A history of traumatic anterior shoulder dislocation is key. Patients report pain, apprehension, and recurrent instability.
• Physical Examination: Special tests (e.g., apprehension test, relocation test) can elicit symptoms of instability.
• Imaging:
  • X-rays: Primarily used to rule out fractures and can sometimes show a bony Bankart fragment, but often underestimate bone loss.
  • MRI (Magnetic Resonance Imaging): The gold standard for visualizing soft tissue injuries like labral tears. An MRI arthrogram (with contrast injected into the joint) provides even clearer delineation of labral detachment and associated capsular injuries.
  • CT Scan (Computed Tomography): Essential for accurately quantifying glenoid bone loss in suspected bony Bankart lesions. 3D reconstructions are particularly useful for surgical planning.

Treatment Approaches: Why the Distinction Matters

The distinction between soft and bony Bankart lesions is crucial for determining the most appropriate treatment strategy and predicting outcomes.

• Conservative Management:

  • For a first-time dislocation, initial conservative management (rest, sling immobilization, followed by physical therapy) may be attempted. However, for true Bankart lesions (soft or bony), surgical intervention is often recommended, especially for active individuals, due to high recurrence rates.

• Surgical Management:

  • For Soft Bankart Lesions: The standard surgical approach is an arthroscopic Bankart repair. This involves reattaching the torn labrum and capsuloligamentous complex back to the anterior glenoid rim using small anchors and sutures. The goal is to restore the normal anatomy and tension of the shoulder stabilizers.
  • For Bony Bankart Lesions: Treatment is more complex due to the presence of bone loss.
    • Small Bony Fragments: If the bone fragment is small and can be reduced and fixed, an arthroscopic repair may still be possible, often requiring more robust fixation.
    • Significant Bone Loss: When there is substantial bone loss (generally >20-25% of the inferior glenoid width), simply reattaching the labrum is often insufficient to restore stability, as the socket itself is compromised. In these cases, bony augmentation procedures are often necessary. The most common procedure is the Latarjet procedure (or a variation), which involves transferring a piece of bone (the coracoid process) with its attached muscles and ligaments to the anterior glenoid rim. This effectively reconstructs the glenoid bone defect and provides an additional "sling" effect from the transferred muscles, significantly enhancing stability and reducing recurrence rates. Other options include iliac crest bone graft transfers.

Rehabilitation and Prognosis

Regardless of the type of Bankart lesion or surgical approach, a structured and progressive rehabilitation program is critical for optimal recovery. This typically involves:

• Initial Immobilization: To protect the repair.
• Gradual Range of Motion: Restoring mobility without stressing the repair.
• Strengthening: Progressive strengthening of the rotator cuff and periscapular muscles to improve dynamic stability.
• Proprioception and Neuromuscular Control: Retraining the joint's awareness and coordinated movement.
• Return to Activity: A phased return to sports or demanding activities, guided by functional assessment.

The prognosis varies. While soft Bankart repairs generally have good outcomes, the risk of recurrence is higher in younger, highly active individuals. Bony Bankart lesions, especially those with significant bone loss, carry a higher risk of recurrent instability if not adequately addressed with bony augmentation. Surgical techniques for both types of lesions have advanced significantly, offering improved stability and functional outcomes for patients committed to their rehabilitation.