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Congenital Vertical Talus

- Discussion:
    - irreducible dorsal dislocation of the navicular on the talus w/ fixed talo-navicular complex;
    - CVT is a common cause of rigid flat foot, which can be isolated, or can occur with chromosomal abnormalities,
           myeloarthropathies (myelomeningocele), & neurologic disorders;
    - pathoanatomy:
            - deformity is usually severe and rigid, with the hind part of the foot locked in equinus angulation under the tibia and the fore
                   part of foot pulled dorsally by unopposed extensor and peroneal muscles;
            - this deformity includes irreducible dorsal dislocation of the navicular on talus as well as calcaneocuboid joint dislocation,
                    contractures of anterolateral muscles, and a tight heel cord and posterior capsule;
            - functioning peroneus longus and brevis muscles combined with a paralytic tibialis posterior pronate and evert the foot;
            - dorsiflexors and extensors of the toes may be intact and may bowstring across ankle joint, whereas the plantar flexors are
                     weak or absent;
            - these imbalances must be considered in the treatment of pt who has congenital vertical talus;
    - associated anomalies:
            - pts w/ congenital vertical talus most commonly may have neural tube defects or neuromuscular disorders;
            - myelomeningocele
                   - CVT occurs more frequently in assoc w/ myelomeningocele than as an isolated congenital deformity;
            - arthrogryposis;
            - tethered cord;
    - diff dx:
            - oblique talus:
                    - milder form of CVT and may respond to non operative treatment;
                    - diagnosis is confirmed on forced plantar flexion lateral in which the talus will align w/ 1st metatarsal (unlike CVT);

- Clinical Presentation:
    - clinically talar head is prominent medially, sole is convex, forefoot is abducted and dorsiflexed, and the hindfoot is in
           - head of talus is prominent at medial sole of foot;
    - flat foot deformity is rigid;
    - sole of foot has a rocker-bottom (convex) deformity;    
    - pts demonstrate peg-leg gait (akward gait w/ limited forefoot pushoff);

- Radiographs:
    - normal foot:
           - w/ normal feet, a line projected thru longitudinal axis of talus falls to dorsal side of navicular on maximum plantar
                  flexion lateral view;
           - since navicular does not ossify until age 3 yrs, it may be better to say that the line should fall to dorsal side of cuboid;
    - CVT foot:
           - key feature of fixed dorsal dislocation of naviclar on neck of talus, equinus position of talus and calcaneus, dorsiflexion of
                   forefoot, and abduction contracture of the foot;
           - in CVT line through talus is plantar to navicular (cuboid) in both resting lateral and plantar flexed views;
           - plantar flexion view:
                  - diagnosis is confirmed by lateral x-ray in maximum plantarflexion, which demonstrates the irreducible
                         talonavicular joint, and in maximum dorsiflexion, which demonstrates fixed equinus;
                         - navicular cannot be reduced on the talus;
                         - plantar flexion fails to realign talus & first metatarsal, confirming diagnosis of a fixed talonavicular
                                 dislocation ("vertical talus");
                         - line drawn thru axis of talus passes plantar to metatarsal axis;

- Non-Operative:
    - conservative treatment has a controversial role in true congenital vertical talus.
    - treatment may be instituted to stretch the skin, soft tissues, and tendons over the dorsum of foot and to facilitate the operation that
          is almost inevitably needed;
          - casting facilitates wound closure;
    - recommended initial treatment is long leg cast with the foot in maximum plantar flexion and inversion; 
    - ref: Congenital talipes equinovarus. A review of current management.

Operative Treatment:
    - surgery is usually delayed until child is about 12 to 18 mo old;
    - initial procedure usually includes:
          - tendo achilles lengthening
          - lengthening of all foot extensors;
          - shortening of the tibialis posterior;
          - extensive posteromedial & posterolateral releases to relocate talonavicular and subtalar joints;
          - peroneus longus or brevis, or both, may be transferred to the insertion of the tibialis posterior or near the navicular or talus, & tibialis 
                  anterior may be transferred to the neck of the talus;
          - posterior ankle/subtalar capsulotomy;
          - peroneal tendon lengthening;
          - calcaneocuboid capsulotomy;
          - reconstruction of spring ligament;
          - talonavicular joint is pinned, & postoperative casting is for 12 weeks;

- Salvage Procedures: (for recurrent deformity)
    - subtalar (Grice-Green procedure) arthrodesis may be needed for recurrence in older child;
    - triple arthrodesis is salvage procedure reserved for symptomatic adolescent foot;
    - talectomy:
          - enucleation of the talus or navicular may be necessary in patient who has a severe, recalcitrant deformity

Treatment of the Congenital Vertical Talus: A Retrospective Review of 36 Feet with Long-Term Follow up.  

Congenital Vertical Talus

Surgical correction of congenital vertical talus under the age of 2 years.  

Congenital convex pes valgus.  

Early Results of a New Method of Treatment for Idiopathic Congenital Vertical Talus.