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Tarsal Coalition & Peroneal Spastic Flatfoot

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Topic updated on 04/14/16 7:09am
Introduction
  • Congenital anomaly that leads to fusion of tarsal bones and a rigid flatfoot 
    • results in syndrome peroneal spastic flatfoot
    • most common coalitions are 
      • calcaneonavicular 
        • most common
      • talocalcaneal
  • Epidemiology
    • demographics
      • incidence varies from 1%-6%
      • most coalitions found are incidental and asymptomatic
    • age of onset
      • calcaneonavicular
        • 8-12 years old
      • talocalcaneal
        • 12-15 years old
  • Pathophysiology
    • mesenchymal segmentation leading to coalition of tarsal bones
    • coalition may be
      • fibrous
      • cartilagenous
      • osseous
  • Pathoanatomy
    • when subtalar joint is restricted by coalition, distal joints overcompensate resulting in
      • flattening of arch
      • valgus hindfoot
      • peroneal spasticity
  • Associated conditions
    • multiple coalitions are associated with
      • fibular deficiency
      • Apert syndrome
Anatomy
  • Biomechanics
    • subtalar joint moves the foot to internal rotation and varus in late stance
Presentation
  • Symptoms
    • pain worsened by activity
      • onset of symptoms correlates with age of ossification of coalition
    • calf pain
      • secondary to peroneal spasticity
    • recurrent ankle sprains
  • Physical exam
    • inspection
      • hindfoot valgus
      • forefoot abduction
    • range of motion
      • limited subtalar motion
      • heel cord contractures
      • arch of foot does not reconstitute upon toe-standing  
Imaging
  • Radiographs
    • recommended views
      • required
        • anteroposterior view
        • standing lateral foot view
        • 45-degree oblique view
          • most useful for calcaneonavicular coalition
        • Harris view of heel
    • findings
      • calcaneonavicular coalition
        • "anteater" sign
          • elongated anterior process of calcaneus
      • talocalcaneal coalition
        • talar beaking on lateral radiograph
          • occurs as a result of limited motion of the subtalar joint
          • irregular middle facet joint on Harris axial view
        • c-sign  
          • c-shaped arc formed by the medial outline of the talar dome and posteroinferior aspect of the sustentaculum tali
  • CT scan
    • necessary to
      • rule-out additional coalitions
      • determine size and extent of coalition
  • MRI
    • may be helpful to visualize a fibrous or cartilaginous coalition
Treatment
  • Nonoperative
    • observation
      • indications
        • asymptomatic cases
    • immobilization with casting or orthotics
      • indications
        • initial treatment for symptomatic cases   
      • outcomes
        • many patients treated conservatively will avoid surgical intervention
  • Operative
    • surgical resection of coalition with interposition of fat graft or extensor digitorum brevis or subtalar arthrodesis  
      • indications
        • resistant cases when nonoperative management fails to relieve symptoms
      • outcomes
        • 80% will experience pain relief
    • subtalar arthrodesis
      • indications
        • role has not been well established
    • triple arthrodesis (subtalar, calcaneocuboid, and talonavicular)
      • indications 
        • advanced coalitions that fail resection
Surgical Techniques
  • Surgical resection of coalition with interposition of fat graft or extensor digitorum brevis
    • approach
      • calcaneonavicular
        • oblique incision just distal to subtalar joint
      • talocalcaneal
        • curved incision medial side of foot
        • develop interval between flexor digitorum longus and neurovascular bundle
    • technique
      • excise bar and leave defect ~1cm in size
      • interpose EDB (calcaneonavicular coalition) or fat graft (talocalcaneal coalition)
      • calcaneal osteotomy may be added to operation when significant valgus is present pre-operatively
    • post-operative
      • short-leg non-weight bearing cast for three weeks

 

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Qbank (10 Questions)

TAG
(OBQ10.22) A 13-year-old female complains of a year long history of anterior and lateral foot and ankle pain. Physical exam demonstrates limited subtalar motion compared to her contralateral foot. A lateral radiograph is shown in Figure A. A selected CT image of the hindfoot is shown in Figure B. What foot deformity is commonly associated with this condition? Topic Review Topic
FIGURES: A   B        

1. Hindfoot varus
2. Rigid pes planus
3. Pes Cavus
4. Equino-cavovarus
5. Rocker bottom foot

PREFERRED RESPONSE ▶
TAG
(OBQ09.203) A 13-year-old girl presents to the office for the first time with a history of occasional ankle sprains while playing soccer. A history reveals activity-related pain localized to the sinus tarsi. Clinical exam demonstrates pes planus without instability. A radiograph is shown in figure A. What is the most appropriate next step in treatment? Topic Review Topic
FIGURES: A          

1. Triple arthrodesis
2. Coalition excision
3. Subtalar arthrodesis
4. Plantar fascia repair
5. Cast immobilization

PREFERRED RESPONSE ▶
TAG
(OBQ07.124) A 10-year-old girl complains of foot pain for the past 4 weeks while playing basketball for her school team. A radiograph is shown in Figure A. What is the most appropriate treatment? Topic Review Topic
FIGURES: A          

1. coalition excision with fat interposition
2. coalition excision with extensor digitorum brevis interposition
3. subtalar arthrodesis
4. 4 weeks of immobilization in a short leg cast
5. excision of accessory navicular

PREFERRED RESPONSE ▶
TAG
(OBQ05.140) A 14 year-old girl has chronic foot pain which has failed to respond to previous surgical coalition resection and soft tissue interposition. A radiograph of her foot is shown in Figure A. A CT scan demonstrates a talocalcaneal coalition with almost complete involvement of the subtalar joint. What is the treatment of choice? Topic Review Topic
FIGURES: A          

1. revision coalition resection and extensor digitorum brevis interposition
2. revision coalition resection and fat interposition
3. tibiotalocalcaneal arthrodesis
4. talonavicular arthrodesis
5. triple arthrodesis

PREFERRED RESPONSE ▶
TAG
(OBQ05.156) A 10-year-old girl has had recurrent left ankle sprains for the past 9-months. She has tried immobilization in a cast for 5-weeks which has failed to provide relief. She is tender to palpation at the tarsal sinus. Radiographs and CT scan of the left foot show an isolated calcaneonavicular coalition and physical exam revealed a neutral hind foot. What is the next best step in management? Topic Review Topic

1. Resection of coalition at the middle facet if <20° hindfoot valgus is present
2. Coalition resection and interposition of extensor digitorum brevis
3. Complete excision of sustentaculum tali
4. Resection of coalition with concomitant calcaneal neck lengthening or medial slide
5. Triple arthrodesis

PREFERRED RESPONSE ▶
TAG
(OBQ04.81) A 14-year-old female presents with 6 months of bilateral foot pain at the tarsal sinus. Clinical images of standing examination and heel rise are shown in Figures A and B, respectively. Radiographs of the left foot are shown in Figure C and D. Which of the following findings most likely is associated with this patient's condition? Topic Review Topic
FIGURES: A   B   C   D    

1. Dynamic supination during swing phase of gait
2. Limited push-off power, limited forefoot contact, and excessive heel contact during stance phase of gait
3. Recurrent ankle sprains
4. Posterior tibial tendon insufficiency
5. Weak tibialis anterior relative to the peroneus longus resulting in first ray plantar flexion

PREFERRED RESPONSE ▶
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