Shoulder Dislocation: Risks, Recurrence, and Management After a Second Injury

What happens if you dislocated your shoulder twice?

Dislocating your shoulder a second time significantly increases the risk of chronic instability, further damage to surrounding soft tissues and bone, and necessitates a more aggressive approach to management and prevention to avoid future recurrences.

Understanding Shoulder Dislocation: A Brief Review

The shoulder joint (glenohumeral joint) is the most mobile joint in the body, allowing for a wide range of motion. This mobility, however, comes at the cost of stability. It is a ball-and-socket joint where the head of the humerus (arm bone) sits in the shallow glenoid fossa of the scapula (shoulder blade). Stability is primarily provided by static restraints like the joint capsule, glenohumeral ligaments, and the labrum (a fibrocartilaginous rim that deepens the socket), and dynamic restraints like the rotator cuff muscles and scapular stabilizers.

A shoulder dislocation occurs when the head of the humerus completely separates from the glenoid fossa. The vast majority (over 95%) are anterior dislocations, where the humeral head moves forward and typically inferiorly.

The Anatomy of Instability: Why Recurrence is Common

The first shoulder dislocation often causes significant damage to the static stabilizers of the joint. When the humeral head is forced out of the glenoid, it can:

• Stretch or tear the joint capsule and glenohumeral ligaments: These structures become lax, reducing their ability to hold the humeral head in place.
• Tear the labrum: Specifically, an anterior dislocation frequently results in a Bankart lesion, a tear of the anterior-inferior aspect of the labrum, often detaching it from the glenoid rim. This significantly compromises the depth of the socket and the attachment point for the glenohumeral ligaments.
• Create bone defects: The humeral head can impact the anterior glenoid rim, causing a bony Bankart lesion (fracture of the glenoid rim). Conversely, the glenoid rim can impact the posterolateral aspect of the humeral head, creating a compression fracture known as a Hill-Sachs lesion. Both bone defects reduce the stability of the joint, making it easier for the humeral head to dislocate again.

After a single dislocation, especially in younger, active individuals, the risk of recurrence is high, ranging from 50% to 90%. A second dislocation indicates that the initial injury likely caused substantial structural damage that was not adequately healed or compensated for, leading to persistent shoulder instability.

Immediate Consequences of a Second Dislocation

When a shoulder dislocates for a second time, the immediate experience is similar to the first, but often with increased severity or recognition:

• Intense Pain: While some individuals report less pain due to increased laxity, it is typically still severe.
• Visible Deformity: The characteristic "squared-off" appearance of the shoulder may be evident.
• Loss of Function: Inability to move the arm.
• Potential for Neurovascular Compromise: Although rare, there is a risk of damage to the axillary nerve (leading to numbness in the deltoid region and weakness in shoulder abduction) or blood vessels. This risk may be slightly elevated with repeated trauma.

Long-Term Implications and Increased Risks

Dislocating your shoulder twice signals a significant level of joint instability and carries several critical long-term implications and increased risks:

• Chronic Instability: This is the primary concern. Each dislocation further stretches and damages the stabilizing structures, making the shoulder progressively more prone to future dislocations, even with minimal force or during everyday activities. This can severely impact quality of life, athletic participation, and occupational function.
• Increased Risk of Rotator Cuff Tears: While more common in older individuals with initial dislocations, repeated trauma can increase the likelihood of tearing one or more of the rotator cuff tendons (supraspinatus, infraspinatus, teres minor, subscapularis), leading to pain, weakness, and impaired shoulder mechanics.
• Nerve Damage: The axillary nerve is particularly vulnerable during anterior dislocations. While transient neuropraxia (temporary nerve stunning) is more common, repeated dislocations increase the risk of more significant or permanent nerve injury, leading to persistent weakness of the deltoid muscle and sensory deficits.
• Exacerbated Labral Tears: The initial Bankart lesion may be worsened, or other labral tears, such as a SLAP (Superior Labrum Anterior to Posterior) lesion, may develop, especially if the second dislocation involves a different mechanism or force.
• Worsening Bone Defects: Existing Hill-Sachs or bony Bankart lesions can become larger with repeated dislocations, further compromising joint congruence and stability. Larger bone defects often necessitate more complex surgical interventions.
• Osteoarthritis: Over time, recurrent dislocations and the associated chronic instability, cartilage damage, and altered joint mechanics significantly increase the risk of developing glenohumeral osteoarthritis, leading to chronic pain, stiffness, and reduced range of motion.
• Psychological Impact: The fear of re-injury (kinesiophobia) can be substantial, leading to avoidance of activities, reduced confidence, and a significant impact on mental well-being and participation in sports or hobbies.

Management and Treatment Strategies

A second shoulder dislocation typically warrants a more aggressive and proactive approach to management than the first.

• Acute Management:

  • Reduction: The humeral head must be promptly and safely relocated back into the glenoid fossa by a trained medical professional.
  • Immobilization: A brief period of immobilization (typically 1-3 weeks) in a sling may be used, though prolonged immobilization can lead to stiffness. The position of immobilization (internal vs. external rotation) is debated, but external rotation may offer some benefits for labral healing.
  • Imaging: X-rays are crucial to confirm reduction and rule out associated fractures. An MRI is often recommended after a second dislocation to thoroughly assess soft tissue (labrum, capsule, ligaments, rotator cuff) and bone damage (Hill-Sachs, bony Bankart).

• Rehabilitation:

  • A structured and supervised physical therapy program is essential. The focus shifts from initial pain management and range of motion to restoring dynamic stability.
  • Strengthening: Emphasis is placed on the rotator cuff muscles (to centrally compress the humeral head into the glenoid) and the scapular stabilizer muscles (to provide a stable base for the shoulder joint).
  • Proprioception and Neuromuscular Control: Exercises to improve the joint's awareness of its position in space and enhance rapid muscle responses are critical for preventing future dislocations.
  • Gradual Return to Activity: A progressive return to sport or high-risk activities is guided by the physical therapist, ensuring adequate strength, stability, and confidence.

• Surgical Intervention:

  • After a second dislocation, especially in young, active individuals, surgery is often strongly considered, as conservative management alone has a high failure rate.
  • Indications: Recurrent dislocations, significant labral tears (Bankart lesion), large bony defects (Hill-Sachs, bony Bankart), or failure of comprehensive non-operative rehabilitation.
  • Common Procedures:
    • Arthroscopic Bankart Repair: The most common procedure, involving reattaching the torn labrum and tightening the stretched capsule and ligaments using anchors.
    • Latarjet Procedure: For cases with significant glenoid bone loss (bony Bankart lesion) or failed Bankart repairs. This involves transferring a piece of bone (coracoid process) with its attached muscles to the front of the glenoid, providing both a bone block and a sling effect from the transferred muscles.

Preventing Further Recurrence

Preventing a third or subsequent dislocation requires a comprehensive strategy:

• Adherence to Rehabilitation: Completing the full course of physical therapy, even after surgery, is paramount.
• Strength and Conditioning: Maintaining strong rotator cuff and scapular stabilizer muscles is crucial for dynamic stability.
• Activity Modification: Avoiding positions or movements known to cause dislocation (e.g., arm abducted and externally rotated in sports like throwing or swimming) may be necessary, especially initially.
• Bracing: While the evidence is mixed, some individuals, particularly athletes, may use shoulder braces during high-risk activities post-rehabilitation or surgery.
• Surgical Consultation: For persistent instability after two dislocations, surgical stabilization is often the most effective way to reduce the risk of further episodes.

When to Seek Professional Help

If you have dislocated your shoulder twice, it is imperative to:

• Seek immediate medical attention for any suspected dislocation to ensure proper reduction and assessment.
• Consult with an orthopedic surgeon or sports medicine specialist to discuss the extent of the damage and the most appropriate long-term management strategy, including the potential need for surgical stabilization.
• Engage in a structured rehabilitation program with a qualified physical therapist to optimize recovery and minimize the risk of future recurrences.