Clavicle Subluxation: Types, Symptoms, Diagnosis, and Treatment

What is Subluxation of the Clavicle?

Subluxation of the clavicle refers to a partial dislocation of the collarbone from one of its articulating joints, most commonly the acromioclavicular (AC) joint or, less frequently, the sternoclavicular (SC) joint, where the joint surfaces maintain some contact despite ligamentous injury.

Understanding the Clavicle and its Joints

The clavicle, commonly known as the collarbone, is a long, slender bone that connects the upper limb to the axial skeleton. It plays a crucial role in supporting the shoulder, allowing for a wide range of arm movements, and protecting underlying neurovascular structures. The clavicle forms two primary joints:

• Sternoclavicular (SC) Joint: Located at the medial (inner) end of the clavicle, this joint connects the clavicle to the sternum (breastbone). It is a saddle-type synovial joint, highly stable due to strong ligamentous support and its unique anatomy, but it allows for significant movement to accommodate shoulder motion.
• Acromioclavicular (AC) Joint: Situated at the lateral (outer) end of the clavicle, this joint connects the clavicle to the acromion, a projection of the scapula (shoulder blade). It is a planar synovial joint, primarily stabilized by the AC ligaments and, more importantly, the powerful coracoclavicular ligaments (conoid and trapezoid ligaments) that connect the clavicle to the coracoid process of the scapula.

Defining Subluxation of the Clavicle

Subluxation is a medical term for a partial dislocation, meaning that the bones forming a joint are no longer perfectly aligned, but their articulating surfaces still maintain some degree of contact. This distinguishes it from a full dislocation, where there is a complete separation of the joint surfaces.

When referring to the clavicle, subluxation typically implies:

• Ligamentous Integrity Compromise: The ligaments supporting the affected joint (either AC or SC) are stretched or partially torn, compromising the joint's stability.
• Joint Instability: The joint may feel unstable, shift, or click during movement, but the clavicle has not completely separated from its joint partner.

Types of Clavicle Subluxation

Subluxation of the clavicle can occur at either the AC or SC joint, with the AC joint being far more commonly affected.

• Acromioclavicular (AC) Joint Subluxation:
  • This is the most frequent type of clavicle subluxation, often referred to as an "AC separation" or "shoulder separation."
  • It typically results from a direct blow to the top or side of the shoulder, or a fall onto an outstretched arm.
  • AC joint injuries are graded based on the severity of ligamentous damage and the degree of clavicle displacement. Subluxations typically correspond to Type I (sprain of AC ligaments, no significant displacement) and Type II (tear of AC ligaments, sprain of coracoclavicular ligaments, mild superior displacement of the clavicle) injuries. Higher grades (Type III and above) involve complete dislocations.
• Sternoclavicular (SC) Joint Subluxation:
  • This is a much rarer injury due to the strong ligamentous support and unique anatomy of the SC joint.
  • It usually results from a direct impact to the front of the chest or shoulder, or an indirect force transmitted through the arm.
  • SC joint subluxations can be classified as anterior (clavicle displaces forward) or posterior (clavicle displaces backward). While anterior subluxations are more common, posterior subluxations are considered more serious due to the proximity of vital structures (trachea, esophagus, major blood vessels) behind the joint, potentially leading to life-threatening complications.

Causes and Risk Factors

The primary cause of clavicle subluxation is trauma that forces the clavicle out of its normal anatomical position.

• Direct Impact: A fall directly onto the top or side of the shoulder (common in AC joint injuries).
• Fall onto an Outstretched Arm: The force is transmitted up the arm to the shoulder girdle.
• Contact Sports: Injuries sustained during sports like football, rugby, hockey, wrestling, or martial arts.
• High-Impact Activities: Cycling accidents, skiing falls, motor vehicle collisions.
• Repetitive Stress: While less common for acute subluxation, chronic overuse or repetitive overhead activities can sometimes contribute to joint instability over time.

Signs and Symptoms

The symptoms of a clavicle subluxation depend on the affected joint and the severity of the injury. Common signs include:

• Pain: Localized pain directly over the AC or SC joint, often worsened by movement of the arm or shoulder.
• Swelling and Bruising: Visible swelling and discoloration around the injured joint.
• Deformity or Bump: A noticeable prominence or "step-off" at the joint line, particularly common in AC joint subluxations (Type II).
• Restricted Range of Motion: Difficulty or pain when lifting the arm overhead, reaching across the body, or performing pushing/pulling movements.
• Tenderness to Touch: Palpable pain upon touching the affected joint.
• Instability or Clicking Sensation: A feeling that the joint is unstable, "giving way," or producing a clicking or grinding sound with certain movements.
• Referred Pain: Pain that may radiate down the arm or into the neck in some cases.
• Specific to Posterior SC Subluxation: Difficulty breathing, swallowing, or voice changes due to pressure on underlying structures.

Diagnosis

Accurate diagnosis of clavicle subluxation involves a combination of clinical assessment and imaging studies.

• Clinical Examination: A healthcare professional will take a detailed history of the injury and conduct a thorough physical examination. This includes:
  • Visual Inspection: Looking for deformity, swelling, or bruising.
  • Palpation: Gently feeling the joint for tenderness and assessing stability.
  • Range of Motion Assessment: Evaluating the patient's ability to move their arm and shoulder in various directions.
  • Special Tests: Performing specific orthopedic tests to assess the integrity of the AC or SC joint ligaments.
• Imaging Studies:
  • X-rays: Standard X-rays are often the first imaging modality used to assess bone alignment, identify fractures, and determine the degree of clavicle displacement. Specific views, such as Zanca views for AC joint injuries or stress views (X-rays taken while holding a weight), may be used to highlight subtle instability.
  • Magnetic Resonance Imaging (MRI): MRI provides detailed images of soft tissues, including ligaments, tendons, and cartilage. It is excellent for assessing the extent of ligamentous damage (e.g., partial vs. complete tears) and ruling out other soft tissue injuries.
  • Computed Tomography (CT) Scan: CT scans provide detailed cross-sectional images of bone and are particularly useful for complex SC joint injuries, especially posterior dislocations, to evaluate the relationship of the clavicle to vital mediastinal structures.

Treatment and Management

Treatment for clavicle subluxation primarily focuses on conservative management, with surgery reserved for specific, more severe cases or persistent instability.

• Conservative Management:
  • Rest and Activity Modification: Limiting activities that aggravate the pain and protecting the injured joint.
  • Ice Application: Applying ice packs to the affected area for 15-20 minutes several times a day to reduce pain and swelling.
  • Pain and Anti-inflammatory Medication: Over-the-counter or prescription non-steroidal anti-inflammatory drugs (NSAIDs) can help manage pain and inflammation.
  • Immobilization: A sling may be used for a short period (typically 1-3 weeks) to support the arm, reduce stress on the joint, and allow the injured ligaments to heal.
  • Physical Therapy: A cornerstone of recovery. A physical therapist will guide a progressive rehabilitation program.
• Surgical Intervention:
  • Surgery is rarely needed for low-grade AC or SC subluxations. It is typically considered for:
    • Higher-grade AC joint injuries (Type III and above) that result in persistent pain or significant functional limitations.
    • Chronic instability of either joint that fails to respond to conservative management.
    • Posterior SC joint dislocations due to the risk of vital structure impingement.
  • Surgical procedures aim to stabilize the joint, often involving reconstruction or repair of damaged ligaments, sometimes with the use of grafts or synthetic materials.

Rehabilitation and Recovery

Rehabilitation is crucial for restoring full function after a clavicle subluxation and typically follows a phased approach:

• Phase 1: Acute Pain and Swelling Management: Focus on rest, ice, pain control, and gentle passive range of motion.
• Phase 2: Restoring Range of Motion: Gradually increasing active and passive range of motion as pain allows.
• Phase 3: Strengthening: Progressive strengthening exercises for the muscles surrounding the shoulder joint, including the rotator cuff, scapular stabilizers (rhomboids, serratus anterior, trapezius), and deltoid.
• Phase 4: Functional and Sport-Specific Training: Incorporating exercises that mimic daily activities or sport-specific movements, focusing on power, endurance, and proprioception (joint awareness). Recovery time varies depending on the severity of the subluxation, but generally ranges from a few weeks for minor sprains to several months for more significant injuries requiring extensive rehabilitation.

Prevention Strategies

While not all clavicle subluxations can be prevented, certain strategies can reduce the risk:

• Proper Technique: Learning and practicing correct technique in sports and activities to minimize awkward falls or impacts.
• Strength and Conditioning: Maintaining strong shoulder girdle muscles can provide better stability and support to the clavicle joints.
• Fall Prevention: Being aware of surroundings, wearing appropriate footwear, and using handrails to prevent falls.
• Protective Gear: Using appropriate protective equipment in contact sports (e.g., shoulder pads).

When to Seek Medical Attention

It is important to seek medical attention if you suspect a clavicle subluxation or any significant shoulder injury. Consult a healthcare professional immediately if you experience:

• Sudden, severe pain in the shoulder or collarbone after an injury.
• Visible deformity, swelling, or a prominent bump over the collarbone.
• Inability to move your arm or shoulder through its full range of motion.
• Numbness, tingling, or weakness in your arm or hand.
• Any signs of a posterior sternoclavicular joint injury, such as difficulty breathing, swallowing, or a change in your voice, as these can indicate pressure on vital structures.

Early diagnosis and appropriate management are key to ensuring optimal recovery and preventing long-term complications from clavicle subluxation.