repeated shoulder dislocation

Recurrent shoulder dislocation is a frequent and serious condition. According to a 25-year follow-up study by Hovelius (JBJS, 2008), the recurrence rate following non-operative treatment reaches 72% in patients under 20. Every subsequent dislocation causes cumulative damage, including progressive bone loss, ligamentous laxity, and extensive labral tearing. Eventually, the shoulder may dislocate during minor daily activities or even while sleeping.

Why Does Recurrent Dislocation Occur?

The primary driver of recurrence is structural damage sustained during the initial dislocation that fails to heal spontaneously, specifically a Bankart Lesion (a tear of the glenoid labrum) and stretching of the joint capsule and ligaments. This damage compromises joint stability, leaving the humeral head vulnerable to displacement.

Factors Increasing Recurrence Risk

• Age: The most significant factor. Recurrence rates are 68–72% for those under 20, decreasing to 14–22% for those over 50.
• Bankart Lesion: A labral tear that rarely heals without surgical intervention.
• Glenoid Bone Loss: Each dislocation erodes the glenoid rim, weakening the “wall” that holds the humeral head in place.
• Hill-Sachs Defect: A compression fracture on the humeral head that acts like a “key,” facilitating dislocation during specific movements.
• Physical Activity: High-impact sports or overhead activities increase risk.
• Hyperlaxity: Individuals with naturally flexible ligaments inherently have lower joint stability.

Is Recurrent Dislocation Harmful?

Yes, recurrent dislocation causes irreversible, cumulative joint damage. Delaying surgery often leads to more complex procedures and poorer functional outcomes.

Consequences of Chronic Instability

• Progressive Bone Loss: After five dislocations, a joint may lose over 25% of the glenoid rim.
• Capsular Stretching: Loss of the natural tension required to hold the joint in place.
• Early-Onset Arthritis: Chronic instability and friction lead to premature cartilage wear.
• Neurological Injury: Approximately 3% of cases involve damage to the axillary nerve, causing numbness or deltoid weakness.
• Psychological Impact: Chronic apprehension leads to the avoidance of social and physical activities.

Diagnosis

Specialized orthopaedic evaluation includes:

1. Clinical Examination: Tests such as the Apprehension Test and Relocation Test to assess instability.
2. MRI: To evaluate labral tears and soft tissue integrity.
3. 3D CT Scan: Essential for measuring glenoid bone loss. If bone loss exceeds 20%, procedures like the Latarjet are required instead of standard Bankart repairs.

Are Shoulder Braces Effective?

Braces provide temporary support, but they do not prevent recurrence or repair structural damage. Relying on them can create a false sense of security, leading to muscle atrophy, joint stiffness, and delayed definitive treatment.

Emergency Protocols

Never attempt to reduce a dislocated shoulder at home. Unprofessional attempts can fracture the humerus or damage neurovascular structures. Immediately immobilize the arm, apply ice, and proceed to the nearest emergency department for professional reduction under sedation.

Definitive Treatment

Surgery is the definitive solution for recurrent instability.

• Arthroscopic Bankart Repair: Fixes the labral tear and tightens the capsule; suitable for patients with <20% bone loss.
• Latarjet Procedure: An open surgery that transfers a bone block to compensate for significant bone loss; it offers superior stability for complex cases.

Frequently Asked Questions (FAQ)

references

• https://www.orthobullets.com/shoulder-and-elbow/3050/traumatic-anterior-shoulder-instability-tubs
• https://isakos.com/GlobalLink/eNewsletter/2025-Volume-1/Recurrent-Anterior-Shoulder-Instability