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paediatric

Tarsal Coalition

advanced
6 min
28 marks
6 questions
Clinical Scenario
A 13-year-old boy presents with a 6-month history of right foot and ankle pain, worse with activity and sports. He has noticed his foot appears flat. He denies trauma. On examination, he has a rigid flatfoot with limited subtalar motion. There is tenderness over the sinus tarsi. Heel valgus does not correct with toe raise. The peroneal muscles appear tight. He has similar but less symptomatic findings on the left.
Lateral weight-bearing radiograph of an adolescent foot demonstrating features of talocalcaneal coalition. There is a positive C-sign (continuous arc from dome of talus to sustentaculum tali). Talar beaking is visible (dorsal spurring of talar head). The subtalar joint appears indistinct. The hindfoot is in valgus. CT is recommended to characterize the coalition (fibrous, cartilaginous, or osseous) and determine resectability.
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Lateral weight-bearing radiograph of an adolescent foot demonstrating features of talocalcaneal coalition. There is a positive C-sign (continuous arc from dome of talus to sustentaculum tali). Talar beaking is visible (dorsal spurring of talar head). The subtalar joint appears indistinct. The hindfoot is in valgus. CT is recommended to characterize the coalition (fibrous, cartilaginous, or osseous) and determine resectability.

Source: Talocalcaneal Coalition Lateral Radiograph • PMC4799062 • CC-BY

Questions

Question 1 (4 marks)

Describe the types of tarsal coalition and their radiographic features.

Question 2 (5 marks)

What are the clinical features and natural history?

Question 3 (6 marks)

Describe the imaging algorithm and specific findings.

Question 4 (5 marks)

What is the treatment algorithm?

Question 5 (4 marks)

Describe coalition resection technique and outcomes.

Question 6 (4 marks)

What are the differential diagnoses for rigid flatfoot?

Exam Day Cheat Sheet

Must Mention

  • •CN (53%) vs TC (37%) coalition
  • •C-sign, talar beaking for TC
  • •Anteater nose, 45° oblique for CN
  • •CT to characterize and measure %
  • •<50% = resection, >50% = fusion
  • •Interposition (fat, EDB) essential

Common Pitfalls

  • •Wrong view for type
  • •Missing C-sign
  • •Wrong resection criteria
  • •No CT mention
  • •Missing interposition
  • •Wrong differential