CLAVICLE FRACTURE

Clavicle Anatomy

The clavicle, commonly known as the collarbone, is an S-shaped bone that connects the sternum (breastbone) medially to the scapula (shoulder blade) laterally. It serves as a structural support, holding the shoulder in position and facilitating a wide range of movements. The clavicle is divided into three main sections:

1. Medial third (Sternal end): Articulates with the manubrium of the sternum.
2. Middle third: The most frequently fractured part of the clavicle.
3. Lateral third (Acromial end): Articulates with the acromion process of the scapula.

Clavicle Fracture Epidemiology

• Clavicle fractures represent 2.6-5% of all fractures in adults.
• These fractures are the most common in children, comprising 10-15% of pediatric fractures.
• Approximately 80% of clavicle fractures occur in the middle third of the bone.
• Males, especially younger males, are more commonly affected, largely due to sports-related injuries.

Mode of Injury

Clavicle fractures generally occur due to:

1. Direct trauma: Such as falling onto the shoulder, often seen in sports injuries, motor vehicle accidents, or falls.
2. Indirect trauma: Like a fall onto an outstretched hand (FOOSH).
3. Birth trauma: In neonates, clavicle fractures can occur during vaginal delivery, particularly in cases of shoulder dystocia.

Allman’s Classification of Clavicle Fractures

1. Group I: Fractures of the middle third (most common).
2. Group II: Fractures of the lateral third.
3. Group III: Fractures of the medial third (least common)

Allman’s Classification of Clavicle Fractures:

Group	Location of Fracture	Description
Group I	Middle third of the clavicle	The most common type, accounting for approximately 80% of clavicle fractures. The middle third is structurally the weakest point.
Group II	Lateral third of the clavicle	These fractures occur near the acromion process and can involve the coracoclavicular ligaments. They are further classified by Neer’s system.
Group III	Medial third of the clavicle	The least common type of clavicle fracture. Located near the sternum and often associated with other injuries such as those involving the chest.

Neer’s Classification of Lateral Clavicle Fractures

Neer’s classification divides lateral third fractures based on the involvement of the coracoclavicular (CC) ligaments:

• Type I: Fractures lateral to the CC ligaments without ligament disruption; stable.
• Type II: Fractures medial to the CC ligaments with ligament disruption; unstable.
  • Type IIA: Conoid and trapezoid ligaments remain attached to the distal fragment.
  • Type IIB: Both ligaments are disrupted.
• Type III: Fractures that extend into the acromioclavicular (AC) joint.
• Type IV: Fractures with periosteal disruption and involvement of soft tissues.
• Type V: Comminuted fractures of the lateral clavicle.

Neer’s Classification of Lateral Clavicle Fractures:

Type	Description	Stability
Type I	Fractures lateral to the coracoclavicular (CC) ligaments, without ligament disruption.	Stable
Type II	Fractures medial to the CC ligaments, with ligament disruption.	Unstable
Type IIA	Conoid and trapezoid ligaments remain attached to the distal fragment.	Unstable
Type IIB	Both conoid and trapezoid ligaments are disrupted.	Unstable
Type III	Fractures extending into the acromioclavicular (AC) joint.	Stable
Type IV	Fractures with periosteal disruption and soft tissue involvement.	Unstable
Type V	Comminuted fractures of the lateral clavicle.	Unstable

Biomechanics of Clavicle Fractures

• The clavicle functions as a strut between the scapula and sternum, helping to maintain the shoulder’s position.
• It absorbs forces transmitted from the upper limb through the acromioclavicular and sternoclavicular joints.
• A direct blow or fall onto the shoulder can cause the clavicle to fail under stress, resulting in a fracture.

Investigations

1. Physical Examination: Findings may include visible deformity, swelling, tenderness over the clavicle, and restricted shoulder movement.
2. Radiographic Imaging:
   • X-rays: The primary imaging modality, typically taken in AP and cephalic tilt views.
   • CT Scan: Used for complex or displaced fractures, especially of the medial third or for preoperative planning.
   • MRI: Rarely needed but helpful for assessing associated soft tissue injuries.

Treatment

The treatment approach depends on the fracture type, degree of displacement, and patient factors such as age and activity level.

Non-surgical (Conservative) Treatment:

• Indications: Non-displaced or minimally displaced fractures, especially in the middle third (Allman Group I).
• Management:
• Sling or figure-of-eight brace: Provides immobilization to support healing.
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• Physical therapy: Introduced after initial healing to restore range of motion and strength.
• Duration: Immobilization for 4-6 weeks, followed by rehabilitation.

Surgical Treatment:

• Indications:
  • Significantly displaced fractures (especially >2 cm of displacement).
  • Open fractures.
  • Neurovascular injury.
  • Risk of non-union or malunion.
  • Comminuted fractures or those involving the lateral third (Neer Type II fractures).
• Surgical Options:
  • Plate fixation: The most common surgical approach, using a contoured plate for internal fixation.
  • Intramedullary fixation: A less invasive option used in some midshaft fractures.
  • External fixation: Rarely used but considered when severe soft tissue injury is present or internal fixation is not feasible.

Complications

• Non-union or malunion: Failure to heal properly, potentially resulting in significant deformity.
• Neurovascular injury: Possible damage to the brachial plexus or subclavian vessels.
• Post-operative issues: These may include hardware irritation, infection, or refracture after hardware removal.
• Shoulder dysfunction: Can arise from altered biomechanics or muscle atrophy during recovery.

Prognosis

Early diagnosis and appropriate management of clavicle fractures are crucial for achieving good functional recovery and minimizing long-term disability.