Congenital vertical talus

definition

· syn. rockerbottom foot

· congenital rigid flatfoot due to talonavicular dislocation

epidemiology

· uncommon

· high association with congenital anomalies and CNS disorders

· myelodysplasia (10% of spina bifida patients have CVT)

· CDH

· arthrogryposis

· trisomy 18

· craniocarpotarsal dystrophy

pathogenesis

· thought to be due to contracture of

· tendo Achilles posteriorly pulling calcaneus into equinus

· extensor digitorum longus anteriorly pulling navicular dorsally

pathology

· talus hypoplastic and in plantarflexion

· fixed dorsal dislocation of navicular on talar neck

· sustentaculum tali blunted

· calcaneus in equinus and valgus

· forefoot abducted

· no extensor retinaculum

· tibialis anterior tendon like bowstring

· all dorsal tendons tethered medial to midline of ankle

clinical features

· plantar aspect of foot convex

· rocker-bottom appearance

· heel in fixed equinus

· tight tendo Achilles

· head of talus prominent

· palpable medially in sole

· forefoot abducted and dorsiflexed at midtarsal joint

radiology

· talus approaches vertical

· may be parallel with tibia

· talonavicular dislocation

· forefoot dorsally displaced on talus

· head of talus medial and plantar

· diagnosis confirmed with extreme plantarflexion view

· relationship of talus to navicular fixed and rigid

differential diagnosis

· severe calcaneovalgus foot

· severe idiopathic flat foot

· valgus everted foot of cerebral palsy

· spurious overcorrection of club foot

treatment

Nonoperative

· rarely successful

· manipulation and casting used to stretch soft tissues

· to prepare skin and soft tissues for surgery

· from birth to age 3-4 mths

Surgery

Early

· performed at same age as clubfoot surgery

· soft-tissue releases to

· correct hindfoot equinus

· correct forefoot calcaneus

· reduce dislocated talonavicular joint

· usually two stages

1. midfoot

· lengthening of EDL, EHL and tib ant

· TN and CC capsulotomies

· TN joint fixed with K wire with foot in plantarflexion

· cast in plantarflexion

2. hindfoot

· tendo Achilles lengthening

· posterior capsulotomy of ankle joint

· cast in neutral

Late

· age 2-6

· subtalar fusion

· adolescent

· triple arthrodesis