congenital talipes equinovarus

definition

· deformity with

· forefoot adduction

· midfoot supination

· hindfoot equinus and varus

· present at birth

epidemiology

· incidence is 1 per 1000 live births

· significant geographic variation

· bilateral in 30%

· more common in boys (2:1)

· strong family history

· if one child has it, 5% chance of next child having it

· if parent also has it, 25% chance

Aetiology

Idiopathic

· multifactorial

· polygenic

· environmental

· environmental factors include

· uterine constriction (oligohydramnios or constriction ring)

· drugs and chemicals (aminopterin, tubocurarine)

Secondary

Genetic

· part of syndromes with mendellian inheritance

· craniocarpotarsal dysplasia (whistling-face syn)

· diastrophic dwarfism

· Larsen’s syndrome

· Pierre-Robin syndrome

Neuromuscular

· associated with

· spina bifida

· cerebral palsy

· arthrogryposis

· muscular dystrophies

· spinal muscular atrophy

pathogenesis

· postulated to be due to

· primary germ plasm defect

· defective cartilage anlage

· abnormal myofibroblasts

· abnormal neuromuscular junction

· anomalous tendon insertions

· retracting fibrosis

pathoanatomy

Bones

· femur, tibia and esp. fibula often all shorter

· no internal tibial torsion

· all tarsal bones abnormal

Talus

· head and neck deviated in plantar and medial direction

· body rotated externally in ankle mortise

· body extruded anteriorly

Calcaneus

· in equinus

· rotated medially

· means that long axis of talus and os calcis are parallel

Navicular

· subluxed medially towards medial malleolus

Cuboid

· subluxed medially

Forefoot

· adducted and supinated

· may be cavus deformity

Lateral malleolus

· located posteriorly near calcaneus

Muscles

· atrophy and contracture of

· triceps surae

· tibialis posterior

· flexor hallucis longus

· flexor digitorum longus

· tendon sheaths thickened around

· tibialis posterior

· peroneals

Ligaments and fascia

· shortening of

· calcaneofibular ligament

· posterior talofibular ligament

· deltoid ligament

· long and short plantar ligaments

· spring ligament

· bifurcate ligament

· plantar fascia

Joint capsules

· contracture of capsules of

· posterior ankle joint

· posterior subtalar joint

· talonavicular joint

· calcaneocuboid joint

clinical features

Of clubfoot

Deformity

· heel equinus

· heel varus

· midfoot supination

· forefoot adduction

· may be cavus

Features

· curved lateral border of foot

· devil’s thumbprint over lateral malleolus

· medial and posterior skin creases

· navicular fixed to medial malleolus

· os calcis fixed to lateral malleolus

General

· calf atrophy

· calf shortening

Of other conditions

· look for

· spinal dysraphism

· arthrogryposis

· other neuromuscular disorders

classification

· depending on degree of correction of forefoot adduction and hindfoot equinus able to be achieved on first assessment

Mild

· correction beyond neutral

· postural form of clubfoot

· 10% will require surgery

Moderate

· correction within 20^o of neutral

· structural form of clubfoot

· 50% will require surgery

Severe

· correction to less than 20^o of neutral

· severe structural deformities

· 90% will require surgery

radiology

Procedure

· perform AP and lateral film in 30^o plantarflexion

· draw

· long axis of talus (parallel to medial border), of calcaneus (parallel to lateral border) and 1st metatarsal on AP

· long axis of talus and calcaneus (parallel to lower borders) on lateral

· measure

· angles between long axis of calcaneus and talus in AP and lateral

· angle between long axis of talus and first ray in AP

· calculate

· talocalcaneal index

· addition of talocalcaneal angles on AP and lateral

Interpretation

Normal foot

· talocalcaneal angle 20-40^o on AP

· ie. long axes diverge

· talocalcaneal angle 20-40^o on lateral

· ie. long axes converge

· means talcalcaneal index > 40^o

· talometatarsal angle negative on AP

· ie. lateral deviation of metatarsal

Club foot

· talocalcaneal angle < 20^o in both views

· ie. long axes parallel

· means talocalcaneal index < 40^o

· talometatarsal angle positive

· ie. medial deviation of metatarsal