Congenital Vertical Talus — Surgical Correction

Indication. Symptomatic, confirmed true congenital vertical talus — a rigid rocker-bottom flatfoot with a persistent dorsal talonavicular dislocation on a forced plantar flexion lateral radiograph (idiopathic or syndromic), that has not corrected with an initial trial of manipulation and casting. The flexible look-alikes (oblique talus, positional calcaneovalgus) reduce on forced plantar flexion and are managed without surgery. Absolute indications. A confirmed true CVT that is rigid with a persistent talonavicular dislocation on the forced plantar flexion view (idiopathic or syndromic); failure of the deformity to correct after an initial trial of manipulation and casting; or an older infant or toddler presenting late with an established deformity. Relative indications. A mild or partially reducible deformity, where a short course of casting may fully correct the talonavicular joint so that only a percutaneous tenotomy and pinning are needed; and syndromic or neuromuscular CVT, where the same pathway applies but with a lower threshold for a limited open reduction and explicit counselling on a higher recurrence rate. Contraindications. Absolute: a flexible oblique talus (reduces on forced plantar flexion and is NOT a CVT — observation, stretching, occasional casting); a fully correctable structural positional deformity such as a severe positional calcaneovalgus foot; or an untreatable, life-limiting underlying condition where foot surgery would not be in the child's interest (a rare, multidisciplinary decision). Relative: severe skin compromise over the dorsum of the foot (defer casting until the skin recovers), or a medically unstable neonate (delay until the child is fit for sedation or anaesthesia). The one decision that matters — exclude the flexible foot. This is the single most important judgement and the most commonly examined point. The forced plantar flexion lateral radiograph resolves it:

Screen the whole child, not just the foot. Because about half of CVT cases are syndromic or neuromuscular, examine the spine for a neural tube defect, the hips for associated dysplasia, and look for arthrogryposis, cerebral palsy, Larsen or Beals syndrome. Arrange spinal and hip imaging and involve paediatrics (and neurology or genetics where relevant) before treating the foot in isolation. Consent specifically for the need for multiple weekly casts, the percutaneous tenotomy and pinning under sedation, the six-to-eight-week cast, the subsequent prolonged bracing commitment, and the risks of recurrence, residual deformity, talar avascular necrosis, stiffness, wound problems and pin-tract infection. Setup. The serial casting is performed without anaesthesia on a settled infant (often after a feed), in an outpatient setting. For the theatre procedure — percutaneous tenotomy and talonavicular pinning — position the child supine with the leg free, under sedation or a light general anaesthetic with full sterile precautions. Mini C-arm fluoroscopy is mandatory to confirm reduction of the talonavicular joint and correct K-wire placement.

The goal: stretch the tight dorsolateral structures and seat the navicular onto the talar head by serial casting, then in theatre confirm and pin the talonavicular reduction under fluoroscopy, correct the residual hindfoot equinus with a percutaneous tendo-Achilles tenotomy, and hold the correction in a long-leg cast — preserving the tenuous talar blood supply throughout. The exposure that matters is the fluoroscopically guided reduction of the talonavicular joint, completed percutaneously when possible and through a small limited dorsolateral incision over the joint when closed reduction is incomplete.

View larger

Casting and bracing protocol | Phase | Timing | Immobilisation | Milestones | |-------|--------|----------------|------------| | Theatre cast | 0 to 6 to 8 weeks | Long-leg cast, knee flexed, K-wire incorporated and bent | Parents counselled on cast care and red-flag signs | | Wire removal | 6 to 8 weeks | K-wire removed in clinic; short further cast if needed | Confirm maintained talonavicular reduction | | Bracing | Months to years | Foot abduction orthosis / moulded AFO — full-time, then night-time | Compliance is the key modifiable factor preventing recurrence | | Surveillance | Through growth | None; review for recurrence, equinus, footwear fit | Forced plantar flexion lateral view if recurrence suspected | Surveillance and follow-up. Review regularly through growth for recurrence (return of forefoot abduction and rocker-bottom), equinus and footwear fit, with radiographic surveillance — again the forced plantar flexion lateral view — when recurrence is suspected. Lifelong follow-up is appropriate, as recurrence, avascular necrosis and stiffness can declare themselves years later. Special case — neuromuscular and syndromic CVT. The reverse-Ponseti pathway still applies, but the threshold for a limited open reduction is lower and the recurrence rate is higher. Treat the foot in the context of the whole child: seating and mobility goals, the natural history of the underlying condition (for example, muscle imbalance in cerebral palsy or arthrogryposis), and the likely need for later soft-tissue balancing or bony surgery. Counsel families honestly — the goal in a syndromic or neuromuscular foot is a plantigrade, braceable, painless foot, and a perfect radiographic reduction may not be achievable or necessary. Special case — late presentation. A child presenting after walking age, or with a long-standing rigid deformity, may not fully correct with casting alone. These feet more often require an open reduction through a limited dorsolateral and medial approach, with soft-tissue balancing, and may need later bony correction. The principles are unchanged: reduce the talonavicular joint, correct the equinus, preserve the talar blood supply, and brace. Complications

Epidemiology. Congenital vertical talus is rare, with an incidence commonly cited at roughly 1 in 10,000 live births. It is bilateral in about half of cases and roughly equally distributed between the sexes. About half of all cases are syndromic or neuromuscular rather than idiopathic, which is why screening the whole child is mandatory. Pathoanatomy — the deformity in three dimensions. Understanding the pathoanatomy is what makes the reduction make sense. The deformity is a fixed dorsal and lateral dislocation of the navicular on the talus, with the talus itself tipped into vertical alignment and the hindfoot locked in equinus.

• The talus: its long axis is nearly vertical, lying close to the long axis of the tibia rather than running forward to the toes; the talar head and neck point plantarward and medially into the plantar arch, producing the firm medial sole prominence and the rocker-bottom.
• The talonavicular joint: the navicular is dislocated dorsally and laterally onto the talar neck, not sitting in front of the talar head where it belongs; the capsule is tight and contracted dorsolaterally and attenuated on the plantar side.
• The hindfoot: the calcaneus is fixed in equinus — the tendo-Achilles and the posterior ankle capsule are tight and will not allow the heel down.
• The forefoot: abducted and dorsiflexed relative to the hindfoot, held there by the tight long toe extensors (extensor hallucis longus, extensor digitorum longus) and the peronei — the very structures the serial casting stretches. The vascular hazard. The talus is the structure most at risk in any CVT surgery. Its blood supply is largely through vessels entering the neck and the tarsal sinus, with limited collateral flow to the body. The historical extensive release stripped and incised widely around the talar head and neck; the consequence was a recognisable rate of avascular necrosis of the talar body. The entire rationale for moving to the minimally invasive Dobbs method was to obtain reduction while leaving the peritalar soft tissues and the talar blood supply as undisturbed as possible. Why the shift away from extensive release. Historically, CVT was treated by an extensive single-stage open soft-tissue release — lengthening of the long toe extensors and peronei, release of the talonavicular and calcaneocuboid capsules, a posterior release for equinus, and reduction held with multiple K-wires. While it could correct alignment, it carried real risks: talar avascular necrosis from extensive peritalar dissection, marked stiffness, wound problems over tight dorsal skin, and a not-trivial recurrence rate. The minimally invasive Dobbs method was developed specifically to obtain comparable correction with far less dissection. Important caveats in the evidence. The best-reported results are in idiopathic CVT; outcomes in syndromic and neuromuscular feet are less consistent, with higher recurrence and residual deformity. Recurrence is closely tied to orthosis compliance — families who do not maintain full-time then night-time bracing recur more often. Long-term follow-up studies are still maturing; mid-term correction is excellent, but lifelong surveillance for recurrence, avascular necrosis and stiffness is appropriate.