Orthopaedic Surgery - Vertical Talus

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Basics

Congenital vertical talus is a rigid congenital foot deformity caused primarily by:

Dorsolateral dislocation of the talonavicular joint.

The deformity produces:

Hindfoot equinus

Forefoot dorsiflexion

Midfoot abduction

and contracture of several:

Tendons and soft-tissue structures.

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Synonyms

Congenital vertical talus is also called:

Congenital convex pes planus

or

Congenital rocker-bottom foot.

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Laterality

The condition may be:

Unilateral

or

Bilateral.

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Associated Disorders

Approximately half of affected patients have an associated:

Neurologic

Genetic

or

Connective-tissue disorder.

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Natural History

The deformity usually develops:

In utero.

An exception may occur in some:

Neurologic disorders

where abnormal muscle balance can produce or worsen the deformity after birth.

Without treatment, the foot generally becomes increasingly:

Rigid

with age.

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Epidemiology

Congenital vertical talus is:

Rare

but has a strong association with other congenital and neurologic:

Conditions.

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Myelomeningocele

Approximately:

5% of children with myelomeningocele

have been reported to develop:

Vertical talus.

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Other Syndromic Associations

The deformity may occur in:

Larsen syndrome

Arthrogryposis

and selected chromosomal disorders.

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Chromosomal Associations

Reported associations include:

Trisomy 13

Trisomy 18

and other:

Chromosomal abnormalities.

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Sex

Boys and girls are affected approximately:

Equally.

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Genetics

Most idiopathic cases are:

Sporadic.

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Familial Cases

Rare familial cases have demonstrated:

Autosomal dominant inheritance

with:

Incomplete penetrance.

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Pathophysiology

The deformity is thought to result from an imbalance between:

Forefoot dorsiflexors

and

Hindfoot plantarflexors.

This imbalance disrupts alignment through the:

Talonavicular joint.

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Ligamentous Laxity

In some children, generalized:

Ligamentous laxity

may contribute to the deformity.

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Structural Changes

The talonavicular joint becomes:

Fixed in dorsal dislocation.

At the same time:

The hindfoot remains in equinus and valgus

while the:

Forefoot is dorsiflexed and abducted.

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Pathological Findings

The muscles and bones are usually structurally:

Normal on histologic examination.

The major abnormality is one of:

Alignment

and

Soft-tissue contracture.

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Associated Conditions

Important associated disorders include:

Arthrogryposis

Myelomeningocele

Larsen syndrome

and

Chromosomal abnormalities.

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Diagnosis

Diagnosis is based on:

Clinical examination

and

Specialized radiographs.

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Signs and Symptoms

Infants are usually initially:

Asymptomatic.

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Symptoms After Walking Begins

If untreated, pressure abnormalities may eventually produce:

Painful plantar calluses

and

Skin irritation.

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Push-Off Dysfunction

Because the foot becomes rounded and mechanically inefficient, patients may have reduced:

Push-off strength

during gait.

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Reversed Arch

The normal longitudinal arch becomes:

Reversed.

The plantar surface therefore appears:

Convex

rather than concave.

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Dorsal Crease

A characteristic:

Deep dorsal crease

may be visible across the:

Midfoot.

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Physical Examination

Examine the entire child rather than focusing only on the:

Foot.

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Screening for Associated Abnormalities

The examination should include:

Spine

Hips

Knees

and

Other extremities

for associated congenital or neurologic:

Abnormalities.

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Strength Examination

Assess motor strength in both:

Lower extremities.

This is particularly important when a:

Neurologic cause

is suspected.

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Standing and Gait

If the child is old enough to walk, observe:

Standing alignment

and

Gait.

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Rocker-Bottom Appearance

The sole of the foot is characteristically:

Convex.

This produces the classic:

Rocker-bottom deformity.

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Hindfoot Equinus

The heel is fixed in:

Equinus

because of shortening of the:

Achilles tendon.

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Hindfoot Valgus

The hindfoot is positioned in:

Valgus.

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Talar Head Prominence

The head of the talus becomes prominent on the:

Medial plantar aspect of the foot.

It may be readily:

Palpable.

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Forefoot Position

The forefoot is:

Abducted

and

Dorsiflexed

through the:

Midtarsal region.

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Increasing Visibility With Age

As subcutaneous fat decreases with age, the characteristic deformity becomes increasingly:

Obvious.

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Distinguishing From Flexible Deformities

True vertical talus is rigid and must be differentiated from:

Calcaneovalgus foot

and

Flexible flatfoot.

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Imaging

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Plain Radiographs

Radiography is essential for confirming the:

Rigid talonavicular dislocation.

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Lateral Radiograph

On the lateral view, the talus is:

Plantarflexed

and often appears nearly:

Vertical.

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AP Radiograph

On the AP view, the talus is typically directed:

Medially.

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Navicular Position

The navicular is displaced:

Dorsally

and lies over the:

Neck of the talus.

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Ossification Limitation

The navicular usually does not ossify until approximately:

3–4 years of age.

Therefore, its position cannot be directly visualized in:

Young infants.

Instead, alignment is inferred from the:

First metatarsal axis.

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Forefoot Alignment

The forefoot is displaced:

Dorsally

and

Laterally or abducted

relative to the hindfoot.

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Calcaneus

The calcaneus remains in:

Equinus.

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Severe Deformity

In marked cases, the talus may become almost:

Parallel to the tibia.

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Stress Plantarflexion View

The most important confirmatory radiograph is the:

Forced plantarflexion lateral view.

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Technique

The examiner maximally plantarflexes the:

Forefoot

while obtaining a:

Lateral radiograph.

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True Vertical Talus

In true congenital vertical talus, the:

Talonavicular joint does not reduce

with plantarflexion.

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Talus–First Metatarsal Relationship

Even with maximal plantarflexion, the axis of the:

First metatarsal

remains dorsal to the:

Talus.

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Normal Relationship

In a flexible foot, the first metatarsal axis becomes approximately:

Collinear with the talar axis

during forced:

Plantarflexion.

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Position of the Navicular

Because the navicular is not ossified in an infant, its location is inferred from its relationship to the:

First ray.

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MRI

MRI is generally:

Not required to evaluate the foot deformity itself.

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Neurologic Evaluation

MRI may be appropriate when there is concern for a:

Spinal abnormality

or another:

Neurogenic cause.

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Pathological Anatomy

The:

Calcaneus

is in equinus and displaced relatively:

Laterally.

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Talus

The talus may be:

Hypoplastic

Medially angulated

and

Plantarflexed.

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Navicular

The navicular remains:

Fixed dorsally

on the talar:

Neck.

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Tendon Contractures

Typical contractures include the:

Achilles tendon

and the:

Dorsiflexor tendons.

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Differential Diagnosis

Important alternatives include:

Calcaneovalgus foot

Flexible flatfoot

and

Oblique talus.

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Calcaneovalgus Foot

Calcaneovalgus is usually a:

Flexible positional deformity

that can often be corrected passively.

Unlike vertical talus, there is no fixed:

Talonavicular dislocation.

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Flexible Flatfoot

Flexible flatfoot becomes more normally aligned when:

Non-weight-bearing

or during:

Toe standing.

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Oblique Talus

Oblique talus may resemble vertical talus on routine standing radiographs.

However, the deformity:

Reduces on forced plantarflexion views.

It is therefore generally considered a form of:

Flexible flatfoot rather than true vertical talus.

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Treatment

The major goals are to:

Reduce the talonavicular joint

Correct hindfoot equinus

and establish a:

Plantigrade, functional foot.

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Serial Casting

Initial treatment commonly consists of:

Serial manipulation and casting.

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Direction of Manipulation

The foot is gradually manipulated into:

Plantarflexion

and

Inversion.

This is essentially the opposite direction used during correction of:

Clubfoot.

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Purpose of Casting

Serial casting attempts to:

Reduce the talonavicular joint

and

Stretch the contracted dorsal soft tissues.

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Incomplete Reduction

Even if casting does not fully reduce the joint, it remains useful because it:

Improves flexibility

and can simplify later:

Surgery.

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Timing

Treatment is most successful when started:

Early in infancy.

Definitive correction is ideally achieved before approximately:

1 year of age.

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Surgical Principle

The central goal of operative treatment is:

Reduction and stabilization of the talonavicular joint.

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Talonavicular Pinning

After reduction, the joint is usually maintained with:

Percutaneous pin fixation.

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Modern Minimally Invasive Approach

Whereas extensive open release was historically common, many children can now be treated with:

Serial casting

followed by:

Closed or limited reduction

Percutaneous talonavicular pinning

and

Achilles tenotomy.

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Achilles Tenotomy

Because hindfoot equinus is nearly always present, the:

Achilles tendon

frequently requires:

Tenotomy or lengthening.

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Dorsiflexor Lengthening

If significant dorsal contracture remains, the:

Anterior tibialis

or other dorsiflexor structures may require:

Lengthening.

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Open Reduction

If the talonavicular joint cannot be reduced closed, a limited:

Open reduction

may be required.

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Medial Capsular Stabilization

Selected cases may require repair or stabilization of the:

Medial joint capsule

to maintain:

Alignment.

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Older Children

Children presenting late may require more extensive procedures because the deformity becomes increasingly:

Rigid.

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Talonavicular Fusion

In selected older children, particularly beyond approximately:

3 years of age

with severe deformity, fusion of the:

Talonavicular joint

may occasionally be considered.

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Triple Arthrodesis

Older children or adolescents with rigid, severe deformity may require:

Triple arthrodesis.

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Late Salvage

In adolescents and adults with neglected deformity, salvage procedures may involve:

Triple arthrodesis

and sometimes substantial:

Talar resection.

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Recurrent Deformity

Recurrence may require:

Soft-tissue reconstruction

and, in more severe cases,

Subtalar fusion.

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Postoperative Care

Percutaneous talonavicular pins are often removed at approximately:

6 weeks.

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Bracing

After cast and pin removal, postoperative:

Bracing

may be used for several:

Months.

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Follow-Up

Patients should be followed throughout:

Childhood

and into:

Adolescence.

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Monitoring Goals

Follow-up should assess:

Foot growth

Alignment

Range of motion

Skin condition

and

Gait function.

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Prognosis

If untreated, congenital vertical talus generally causes progressive:

Functional impairment.

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Untreated Deformity

Abnormal plantar pressure may lead to:

Painful calluses

Skin breakdown

and reduced:

Push-off.

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Treated Deformity

After treatment, functional outcome depends largely on:

Quality of reduction

and preservation of:

Hindfoot and midfoot motion.

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Early Treatment

Early reduction generally provides the best chance of achieving a:

Plantigrade

Painless

and

Functional foot.

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Complications of No Treatment

Potential consequences include:

Painful plantar calluses

Skin ulceration

Abnormal pressure distribution

and

Poor push-off strength.

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Treatment Complications

Potential complications include:

Foot stiffness

Residual valgus

Residual varus

Recurrent deformity

and need for:

Additional surgery.

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Patient Monitoring

Even after successful correction, periodic examination is necessary to ensure:

Normal growth

and maintenance of:

Foot alignment.

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Clinical Summary

Definition: Congenital vertical talus is a rigid rocker-bottom foot deformity caused by fixed dorsolateral dislocation of the talonavicular joint.

Typical alignment: Hindfoot equinus and valgus, with a dorsiflexed and abducted forefoot.

Important association: About half of patients have an underlying neurologic, genetic, or connective-tissue disorder.

Key examination: Convex plantar surface, medial plantar prominence of the talar head, fixed equinus, dorsal midfoot crease, and rigid forefoot dorsiflexion.

Diagnostic radiograph: The forced plantarflexion lateral view; in true vertical talus, the talonavicular relationship does not reduce.

Differential: Calcaneovalgus foot, flexible flatfoot, and oblique talus, which corrects on plantarflexion stress imaging.

Initial treatment: Early serial casting into plantarflexion and inversion.

Definitive treatment: Usually talonavicular reduction and pinning with Achilles tenotomy or lengthening.

Prognosis: Best with early correction; untreated deformity leads to abnormal plantar pressure, painful calluses, poor push-off, and progressive disability.

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Key Principle

Congenital vertical talus is a rigid congenital talonavicular dislocation producing a rocker-bottom foot.

The characteristic deformity combines:

Hindfoot equinus and valgus

with

Forefoot dorsiflexion and abduction.

The diagnosis is confirmed using a:

Forced plantarflexion lateral radiograph, which demonstrates failure of the talonavicular joint to reduce.

Treatment should begin early with:

Serial manipulation and casting, followed by:

Talonavicular reduction and pin fixation with correction of Achilles and other tendon contractures.

Early treatment offers the best chance of achieving a:

Plantigrade, painless, functional foot, whereas delayed or untreated disease may require:

Fusion or other salvage procedures.