Sternoclavicular Joint Injuries: Most Common Types, Symptoms, and Treatment

What is the most common injury to the sternoclavicular joint?

The most common injury to the sternoclavicular (SC) joint is a sprain, specifically a Grade I or II sprain, which involves overstretching or partial tearing of the joint's supporting ligaments.

Understanding the Sternoclavicular (SC) Joint

The sternoclavicular (SC) joint is a critical articulation that connects the upper limb to the axial skeleton. It is formed by the medial end of the clavicle (collarbone) and the manubrium (the uppermost part of the sternum or breastbone). Despite its relatively small size, the SC joint is incredibly robust, primarily due to a strong capsule, a tough intra-articular disc, and powerful surrounding ligaments, including the anterior and posterior sternoclavicular ligaments, the interclavicular ligament, and the costoclavicular ligament.

Key Anatomical Features:

• Clavicle: Medial end articulates with the sternum.
• Manubrium: Superior aspect provides the sternal facet.
• Articular Disc: A fibrocartilaginous disc enhances congruence and absorbs shock.
• Ligaments: Provide significant stability, preventing excessive motion.

Functional Significance: The SC joint is the only true bony articulation between the upper limb and the trunk. It acts as a pivot point for shoulder girdle movements, allowing for elevation, depression, protraction, retraction, and rotation of the clavicle, which are essential for full range of motion of the arm.

Sternoclavicular Joint Sprains: The Most Common Injury

Given the SC joint's robust ligamentous support, significant force is typically required to injure it. While severe injuries like dislocations (Grade III sprains) can occur, the most frequently encountered injury is a sternoclavicular joint sprain. These are classified based on the degree of ligamentous damage:

• Grade I Sprain: Involves overstretching of the SC ligaments without macroscopic tearing. The joint remains stable.
• Grade II Sprain: Characterized by a partial tear of the SC ligaments, leading to some instability and subluxation (partial dislocation) of the joint. The clavicle may be slightly displaced but often reduces spontaneously.
• Grade III Sprain: A complete rupture of the SC ligaments, resulting in a full dislocation of the joint. This is a more severe injury and less common than Grade I or II sprains. Dislocations can be anterior (more common) or posterior (less common but more dangerous due to proximity to vital structures).

The high prevalence of Grade I and II sprains is due to the threshold of force required. While the joint is strong, it can be pushed beyond its physiological limits, leading to ligamentous strain before a full tear or dislocation occurs.

Mechanisms of Injury

SC joint injuries typically result from direct or indirect trauma to the shoulder or chest.

Common Mechanisms Include:

• Direct Blow: A direct impact to the front or side of the clavicle or shoulder, often seen in contact sports (e.g., football, rugby, hockey) or motor vehicle accidents (e.g., shoulder striking a dashboard).
• Indirect Force:
  • Fall on an Outstretched Hand (FOOSH): The force transmits up the arm to the shoulder girdle and then to the SC joint.
  • Fall onto the Shoulder: Landing directly on the shoulder, driving the clavicle medially.
  • Sports Collisions: Especially those involving forceful impacts to the chest or shoulder.

Direction of Dislocation:

• Anterior Dislocation: The medial end of the clavicle displaces forward (anteriorly) and superiorly. This is the more common type of dislocation and generally less complicated.
• Posterior Dislocation: The medial end of the clavicle displaces backward (posteriorly) and inferiorly. While less common, this type is considered a medical emergency due to the close proximity of the clavicle to vital structures such as the trachea, esophagus, subclavian artery and vein, and brachial plexus. Compression or laceration of these structures can lead to life-threatening complications.

Recognizing SC Joint Injuries: Symptoms

The symptoms of an SC joint injury vary depending on the severity but generally include:

• Pain: Localized pain over the SC joint, which often worsens with shoulder and arm movements (e.g., reaching across the body, lifting the arm overhead).
• Swelling and Bruising: Visible around the joint area.
• Deformity: In cases of dislocation (Grade III), a noticeable bump or depression may be present at the joint. For anterior dislocations, the clavicle end may be visibly protruding. For posterior dislocations, a depression may be seen, or the shoulder on the affected side may appear shortened or protracted.
• Limited Range of Motion: Difficulty or pain with moving the arm, especially in abduction (lifting away from the body) or flexion (lifting forward).
• Clicking or Popping Sensation: May be felt or heard during movement, particularly if the joint is unstable.
• Respiratory or Vascular Symptoms (Posterior Dislocation): Difficulty breathing, hoarseness, difficulty swallowing, or signs of vascular compression (e.g., numbness, tingling, coolness, or diminished pulse in the arm) are red flags indicating a posterior dislocation and warrant immediate medical attention.

Diagnosis

A thorough diagnosis involves a combination of clinical assessment and imaging studies.

• Clinical Examination: The healthcare provider will assess the mechanism of injury, palpate the SC joint for tenderness, swelling, and deformity, and evaluate the range of motion and stability of the shoulder. Comparison to the uninjured side is crucial.
• Imaging Studies:
  • X-rays: Standard X-rays can be challenging to interpret for SC joint injuries due to overlapping bony structures. Specialized views (e.g., Serendipity view, oblique views) may be used to better visualize the joint.
  • CT Scan (Computed Tomography): This is often the preferred imaging modality for SC joint injuries. It provides detailed cross-sectional images, clearly demonstrating the relationship between the clavicle and sternum, identifying the direction of dislocation, and assessing for associated fractures or soft tissue damage. It is particularly valuable for diagnosing posterior dislocations.
  • MRI (Magnetic Resonance Imaging): While not typically the first choice for acute dislocations, MRI can be useful for assessing soft tissue injuries, such as ligamentous tears, articular disc damage, or chronic instability.

Treatment Approaches

Treatment for SC joint injuries depends on the severity and type of injury.

Conservative Management

Most SC joint sprains (Grade I and II) and stable anterior dislocations are managed conservatively.

• Rest and Immobilization: A sling or figure-of-eight bandage may be used for a short period (1-3 weeks) to immobilize the joint and allow healing.
• Ice and Pain Management: Applying ice to the affected area helps reduce swelling and pain. Over-the-counter or prescription pain relievers and anti-inflammatory medications can be used.
• Physical Therapy: Once pain subsides, a structured rehabilitation program is initiated. This focuses on:
  • Restoring Range of Motion: Gentle exercises to regain full shoulder and arm movement.
  • Strengthening: Exercises to strengthen the muscles surrounding the shoulder girdle (e.g., deltoids, rotator cuff, scapular stabilizers) to improve joint stability.
  • Proprioception and Neuromuscular Control: Exercises to improve joint awareness and coordination.

Surgical Intervention

Surgery is less common but may be necessary for specific cases.

• Posterior Dislocation: These are often considered emergencies and require urgent reduction (repositioning of the joint). This may be a closed reduction (manual manipulation under anesthesia) or an open reduction if closed methods fail or if there is neurovascular compromise.
• Irreducible Anterior Dislocation: If an anterior dislocation cannot be manually reduced or if it is chronically unstable and symptomatic.
• Chronic Instability: For patients experiencing persistent pain and instability despite conservative management, surgical reconstruction of the ligaments may be considered.
• Associated Fractures: If there are significant fractures of the clavicle or sternum accompanying the SC joint injury.

Rehabilitation and Prevention

Rehabilitation is crucial for optimal recovery and preventing long-term complications.

Rehabilitation Phases:

1. Acute Phase (Pain and Inflammation Control): Focus on rest, ice, compression, and elevation (RICE), pain medication, and gentle passive range of motion.
2. Recovery Phase (Restoring Motion and Strength): Gradually introduce active range of motion exercises, followed by progressive strengthening of the shoulder girdle muscles.
3. Functional Phase (Return to Activity): Sport-specific or activity-specific drills, proprioceptive training, and gradual return to full activity under supervision.

Prevention Strategies:

• Proper Technique: In sports and activities, learning and maintaining correct biomechanics can reduce the risk of injury.
• Protective Equipment: Wearing appropriate padding or protective gear in contact sports.
• Strength and Conditioning: Developing strong muscles around the shoulder girdle can enhance joint stability and resilience.
• Awareness: Being mindful of surroundings and avoiding high-risk situations that could lead to falls or impacts.

Prognosis and Recovery

The prognosis for SC joint injuries is generally good, especially for sprains and well-managed anterior dislocations. Most individuals recover full function. However, recovery time varies:

• Grade I Sprains: May resolve within a few weeks.
• Grade II Sprains: Can take 4-6 weeks or longer.
• Dislocations (Grade III): Recovery can take several months, with full return to high-impact activities potentially taking 3-6 months or more, depending on the need for surgery.

Potential Long-Term Complications:

• Chronic Pain: Persistent discomfort around the joint.
• Instability: A feeling of the joint "giving way" or dislocating repeatedly.
• Osteoarthritis: Post-traumatic arthritis may develop in the joint over time, especially after severe injuries.
• Cosmetic Deformity: A persistent bump from an unreduced anterior dislocation.

Conclusion

While the sternoclavicular joint is remarkably strong and resilient, the most frequent injury it sustains is a sprain, typically of Grade I or II severity. These injuries, though less dramatic than full dislocations, underscore the importance of this vital articulation in upper limb function. Understanding the mechanisms, recognizing the symptoms, and adhering to appropriate treatment and rehabilitation protocols are essential for optimal recovery and maintaining the long-term health of this critical joint.