What are the radiographic findings for pes cavus with apophysitis of the distal tibia growth plate?

Radiographic Findings for Pes Cavus with Apophysitis of Distal Tibia Growth Plate

MRI is the preferred imaging modality for diagnosing apophysitis of the distal tibia growth plate in patients with pes cavus, as it provides superior visualization of bone marrow edema, soft tissue inflammation, and early changes in the growth plate that may not be apparent on plain radiographs. 1

Initial Radiographic Assessment

Plain Radiographs (X-rays)

• Weight-bearing lateral and anteroposterior views of the foot and ankle

  • Pes cavus findings:
    • Increased height of the medial longitudinal arch
    • Plantarflexion of the first ray
    • Calcaneal verticality (increased calcaneal pitch angle >30°)
    • Claw toe deformities may be visible

• Distal tibia growth plate findings:

  • Early apophysitis may show minimal or no changes on plain radiographs 1
  • Possible findings include:
    • Widening of the growth plate
    • Irregular sclerosis of the growth plate
    • Periosteal reaction along the metaphysis
    • Soft tissue swelling around the ankle 1, 2

Plain radiographs have limited sensitivity for early apophysitis, as bone destruction may take up to 3 weeks to become visible after symptom onset 1.

Advanced Imaging

MRI (Recommended)

• Most sensitive modality for apophysitis detection 1, 2

• Key findings:

  • Bone marrow edema in the distal tibial epiphysis and metaphysis
  • Increased T2 signal intensity within the growth plate
  • Periosteal edema and inflammation
  • Possible soft tissue edema adjacent to the growth plate
  • Widening of the physis with fluid signal 1

• Optimal MRI sequences:

  • T1-weighted images: evaluate bone marrow and anatomical structures
  • Fluid-sensitive sequences (T2-weighted fat-suppressed or STIR): detect edema and inflammation
  • Post-contrast T1-weighted fat-suppressed images: enhance visualization of inflammatory changes 2

CT Scan

• Consider when MRI is contraindicated or unavailable
• Better than plain radiographs for detecting:
  • Subtle bone erosions
  • Early growth plate irregularities
  • Fragmentation of the apophysis 3
• CT shows significantly more fragments than plain radiographs in growth plate injuries 3
• Limited in evaluation of bone marrow edema and soft tissue inflammation 1

Radiographic Findings Based on Stage of Disease

Early Stage

• MRI: Bone marrow edema and increased T2 signal intensity in the growth plate
• Plain radiographs: May appear normal or show minimal soft tissue swelling

Progressive Stage

• MRI: Increased bone marrow edema, periosteal reaction, possible widening of growth plate
• Plain radiographs: Widening of growth plate, irregular sclerosis, periosteal reaction

Late Stage

• MRI: Persistent bone marrow edema, possible growth plate irregularity
• Plain radiographs: Sclerosis, possible growth arrest lines

Clinical Correlation

The radiographic findings should be interpreted in conjunction with clinical presentation:

• Heel pain
• Pain with activity
• Tenderness over the distal tibial growth plate
• Associated high-arched foot (pes cavus)

Common Pitfalls

1. Relying solely on plain radiographs may lead to missed diagnosis, as early apophysitis often shows normal findings on X-ray 2, 4

2. Confusing normal developmental variations with pathology - the secondary ossification centers can have variable appearances during normal development 5

3. Overlooking associated conditions - pes cavus may be associated with underlying neurological disorders that should be evaluated with appropriate imaging

4. Misclassifying growth plate injuries - CT reveals significantly more fragments and better characterizes fracture patterns in growth plate injuries compared to plain radiographs 3

For comprehensive evaluation of a patient with pes cavus and suspected apophysitis of the distal tibia growth plate, MRI provides the most detailed assessment of both the bony and soft tissue components of the condition.