Ankle fractures in Children

Courtesy: Kaye Wilkins, Lynn Staheli , www.global-help.org

 Pediatric Ankle Fractures (Distal Tibia & Fibula)

Key Concept

• In children  physis is weaker than ligaments
• So  injuries occur through growth plate (physeal fractures) rather than ligament tears
• Hence: better called
  “Fractures around the ankle in the skeletally immature”

 Classification

 Not very useful:

• Salter-Harris classification (limited value for ankle decision-making)

 Most useful:

Mechanism-based classification (Pediatric counterpart of Lauge-Hansen)

Goals of Classification

1. Predict fracture pattern
2. Guide treatment
3. Predict complications

 Main Injury Patterns

 Supination–Inversion Injury (Most common)

 Stage 1

• Injury: distal fibular physis
• Often undisplaced
• Mimics ankle sprain

 Clinical:

• Tenderness over fibular physis (NOT ligaments)

 Treatment:

• Functional:
  • Air cast / brace
  • Early mobilization

Complication:

• Chronic pain due to muscle weakness (immobilization)

 Stage 2

• Medial side: compression injury
• Often Salter III/IV medial malleolus

 Important:

• Crushing injury  high risk of growth arrest

Treatment:

• Anatomical reduction
• Fixation with screw (compression)
• Check joint congruity (arthrogram)

 Complications:

• Physeal arrest  varus deformity
• Fibular overgrowth
• Ankle incongruity  arthritis

2 Pronation–External Rotation Injury

 Features:

• Medial: avulsion fracture (tension)
• Lateral: fibular fracture (diaphyseal/metaphyseal)

 Deformity:

• Valgus

Treatment:

• Usually closed reduction + cast
• If unstable  smooth K-wire (central placement)

 Complication:

• Rare growth arrest (usually symmetrical)

 Special Issue:

• Periosteal interposition  failed reduction

If gap persists  OPEN REDUCTION

3 Supination–External Rotation Injury

Sequence:

1. Tibia fails first
2. Then fibula

Deformity:

• External rotation

 Treatment:

• Closed reduction (internal rotation)
• Fix if unstable

 Complication:

• Residual external rotation deformity

4 Supination–Plantar Flexion Injury

 Features:

• Posterior tibial fracture (avulsion)
• Fibular greenstick

 Treatment:

• Reduction with:
  • Knee flexion
  • Ankle plantarflexion
• Fix if unstable

 Special Adolescent Injuries

 5 Juvenile Tillaux Fracture

• Avulsion of anterolateral distal tibia
• Caused by:
  pull of anterior inferior tibiofibular ligament

 Occurs because:

• Medial physis closed
• Lateral still open

 Treatment:

• Screw fixation (mandatory if displaced)

 Complication:

• Articular incongruity ? arthritis

 6 Triplane Fracture

 Involves 3 planes:

1. Sagittal (epiphysis)
2. Coronal (metaphysis)
3. Transverse (physis)

 Diagnosis:

• X-ray + CT scan (essential)

 Treatment:

• Closed/open reduction
• Screw fixation in correct planes

 Complication:

• Rare growth arrest (growth nearly complete)

 Important Clinical Pearls

 Always check:

• Mortise view (mandatory)
• Joint congruity

 Fibula fracture rule:

If fibula fractured  suspect tibial injury

 Reduction principles:

• Reverse mechanism of injury
• Achieve:
  • Anatomical reduction
  • Stable fixation

 Follow-up:

• Look for Harris growth arrest lines
• Asymmetry  growth arrest

 Most Important Complication

 Physeal Arrest

Leads to:

• Angular deformity (varus/valgus)
• Limb length discrepancy (less common)
• Ankle arthritis

 Management of Growth Arrest

• Fibular epiphysiodesis
• Tibial osteotomy (e.g., opening wedge)
• Bar resection (if early)

 Exam Summary Line

Best classification in pediatric ankle fractures = Mechanism-based (supination/pronation patterns), not Salter-Harris