Skewfoot (Pediatric)

Synonyms
Skew foot, serpentine foot, z-foot

INTRODUCTION

Definition

A deformity that consists of an adducted forefoot and hindfoot valgus with plantar flexion of the talus.

Epidemiology

Rare condition.

Patoanatomy

Forefoot: The first metatarsal bone is adducted and plantar flexed on the medial cuneiform, which leads to marked adductus deformity of the forefoot.
Midfoot
  • The midfoot lies in abduction with lateral displacement of the navicular on the head of the talus.
  • The navicular may also lie dorsally subluxed in relation to the talus.
Hindfoot
  • Hindfoot lies in valgus with pronation and inward rotation of the talus, w/ lateral subluxation of the navicular on the talar head.
  • The achilles tendon is contracted.

Classification

Berg classification
Divides the condition into four subtypes:
  • Simple MTA: MTA.
  • Complex MTA: MTA, lateral shift of midfoot.
  • Skew foot: MTA, valgus hindfoot.
  • Complex skew foot (serpentine foot): MTA, lateral shift, valgus hindfoot.

Napiontek classification
Napiontek proposed a classification scheme to distinguish four clinical types of the deformity:
  • Congenital idiopathic skewfoot.
  • Congenital skewfoot associated with syndromes or systemic disorders.
  • Neurogenic skewfoot.
  • Iatrogenic skewfoot.

Differential Diagnosis

Metatarsus adductus: It is not always be possible to different these disorders in infants. Assessment of hindfoot valgus may be difficult due to the fat pad in children under 1 year of age.

CLINICAL FEATURES

Symptoms

No specific symptoms.

Signs

Patients may become symptomatic at the talar head or the base of the fifth metatarsal.

DIAGNOSIS

Conventional Radiography

Projections: Weight-bearing frontal (AP) and lateral radiographs of the foot.
Findings
  • AP view: A combination of abduction at mid tarsal joints and adduction of metatarsals gives foot z configuration. The  mid-talar axis will generally be medial to base of first metatarsal.
  • Lateral view: Shows a reduction in calcaneal pitch and plantar flexion of talus.

TREATMENT

Overview

Generally observed and in severe cases treated with surgery.

Nonoperative Treatment

  • Nonoperative treatment is generally ineffective in changing the shape of the foot.
  • Consider varus hindfoot molding (to avoid valgus stress on the hindfoot) if casts are applied to correct the forefoot adductus component.

Operative Treatment

Indication: Persistent pain.
  • Surgery should generally be avoided if possible, since there is deformity in the forefoot, midfoot, and hindfoot which essentially means that the
    entire foot has to be reconstructed inorder to re-establish a functional relationaships;
  • Surgery should be delayed until after age of 6 years.
Method: Combined opening wedge medial cuneiform osteotomy and calcaneal osteotomy (for hindfoot valgus).
  • Opening wedge osteotomy of the calcaneus is done to correct mid-tarsal abduction deformity and to position the sustentaculum to elevate neck of the talus.
  • Opening wedge osteotomy of the medial cuneiform is done to correct the forefoot adductus.00

Operation Methods

Opening wedge and closing wedge osteotomies:
  • Indications: Symptomatic deformity that significantly limits function. Operative treatment is difficult and the deformity is often accepted and observed.
  • Method
    • Calcaneal osteotomy for hindfoot valgus.
    • Possible midfoot osteotomies to correct midfoot and forefoot deformities.
    • Multiple metatarsal osteotomies with forefoot pinning and tarsometatarsal capsular release (Hamen procedure).
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References