summary Congenital Vertical Talus is a rare congenital condition caused by neuromuscular or chromosomal abnormalities in neonates that typically presents with a rigid flatfoot deformity. Diagnosis is made with forced plantar flexion lateral radiographs that show persistent dorsal dislocation of the talonavicular joint. Treatment is usually serial manipulation and casting followed by surgical release and talonavicular reduction and pinning at age 6-12 months. Epidemiology: Incidence rare, 1:150,000 births Demographics M:F ratio of 2:1 Anatomic location 50% bilateral Etiology Pathoanatomy rigid foot deformity irreducible dorsolateral navicular dislocation vertically oriented talus calcaneal eversion with attenuated spring ligament soft tissue contractures displacement of peroneal longus and posterior tibilais tendon so they function as dorsiflexors rather than plantar flexors contracture of the Achilles tendon Genetics a positive family history is present in up to 20% of patients HOXD10 gene mutation (transcription factor) Associated conditions 50% associated with neuromuscular disease or chromosomal aberrations Myelomeningocele Arthrogryposis Diastematomyelia congenital dislocation of the hip cerebral palsy spinal muscular atrophy Presentation Physical exam rigid rockerbottom deformity fixed hindfoot equinovalgus due to contracture of the Achilles and peroneal tendons rigid midfoot dorsiflexion secondary to the dislocated navicular forefoot abducted and dorsiflexed due to contractures of the EDL, EHL and tibialis anterior tendons prominent talar head can be palpated in medial plantar arch on exam produces a convex plantar surface gait abnormality patient may demonstrate a "peg-leg" or a calcaneal gait due to poor push-off power limited forefoot contact, excessive heel contact neurologic deficits a careful neurologic exam needs to be performed due to frequent association with neuromuscular disorders Imaging Radiographs recommended views AP, oblique and lateral foot findings lateral vertically positioned talus & dorsal dislocation of navicular line along long axis of talus passes below the first metatarsal-cuneiform axis before ossification of navicular at age 3, the first metatarsal is used as a proxy for the navicular on radiographic evaluation AP talocalcaneal angle > 40° (20-40° is normal) alternative views forced plantar flexion lateral radiograph is diagnostic shows persistent dorsal dislocation of the talonavicular joint oblique talus reduces on this view Meary's angle > 20° (between line of longitudinal axis of talus and longitudinal axis of 1st metatarsal) forced dorsiflexion lateral reveals fixed equinus MRI neuraxial imaging should be performed to rule out neurologic disorder Differential Oblique talus anatomic variant talonavicular subluxation that reduces with forced plantarflexion of the foot treatment is generally observation, shoe inserts vs casting some require surgical pinning of the talonavicular joint and achilles lengthening for persistent subluxation Calcaneovalgus foot deformity Posteromedial tibial bowing Tarsal coalition Paralytic pes valgus Pes planovalgus Treatment Nonoperative serial manipulation and casting indications indicated preoperatively to stretch the dorsolateral soft-tissue structures foot is manipulated into inversion and plantarflexion typically still requires closed vs open pinning of the talonavicular joint with percutaneous achilles tenotomy Operative surgical release and talonavicular reduction and pinning indications indicated in most cases performed at 6-12 months of age technique involves pantalar release with concomitant lengthening of peroneals, Achilles, and toe extensors talonavicular joint is reduced and pinned while reconstruction of the plantar calcaneonavicular (spring) ligament is performed concomitant tibialis anterior transfer to talar neck minimally invasive correction indications new technique performed in some centers to avoid complications associated with extensive surgical releases technique principles for casting are similar to the Ponseti technique used clubfoot serial casting utilized to stretch contracted dorsal and lateral soft tissue structures and gradually reduced talonavicular joint once reduction is achieved with cast, closed or open reduction is performed and secured with pin fixation percutaneous achilles tenotomy is required to correct the equinus deformity talectomy indicated in resistant case triple arthrodesis as salvage procedure Complications Missed vertical talus reconstructive options are less predictable after age 3, and patients may require triple arthrodesis as salvage procedure Prognosis Poor in untreated cases and associated with significant disability