Background

Definition

 

Congenital Talipes Equinovarus

 

Congenital abnormality of the foot characterised by 

- hindfoot equinus & varus 

- forefoot Adduction

- midfoot Supination

 

Latin: talus - ankle / pes - foot / equinus - horse like

 

Clinical

 

Foot

- pipe stem calf

- short wide foot

- small heel

- curved lateral border

- short first ray ray

 

Short T Achilles

 

LLD

 

ER torsion tibia

 

Epidemiology

 

1:1000 live births

- 1/1000 Caucasian

- 5/1000 Polynesians

- 0.5/1000 Asian

 

Boys 2:1

 

Bilateral 30-50%

 

Genetics

 

Twin studies

- 33% risk in monozygotic twins

- 3% dizygotic twins

- i.e. is not just the placental environment

 

Sibling or parent

- 3% chance

- 30x increased risk

 

Sibling and parent

- 10 - 20% risk

 

Deletion on chromosome 2

 

Associations

 

Spina bifida & arthrogryposis (teratogenic)

 

Plus

- cerebral palsy

- muscular dystrophies

- spinal muscular atrophy

 

Theories of pathogenesis

 

1.  Fetal development arrest in fibular phase

- during first and second months leg and foot coplanar

- by beginning of third month foot is in 90o of equinus, has supinated & adducted with plane at right angles to leg

- by the middle of the 3rd month the equinus has corrected

- by the end of the third month the supination and adduction has corrected to the adult position

- Bohm postulated arrest in the first phase in week 5

 

2.  Retracting fibrosis (Ippolito and Ponseti)

- decrease in size & number of muscle fibres in posteromedial muscles

- ? fibrous tissue in muscles, tendon sheaths & surrounding fascia

- marked shortening and thickening of the tibionavicular and plantar calcaneonavicular ligaments   

 

3.  Neurogenic theory

- minor innervation changes in posterior muscles

- subsequent fibrosis and shortening

 

4.  Myogenic theory

- myofibroblasts in medial fascia

 

5.  Vascular theory

- anterior tibial artery / dorsalis pedis frequently missing

 

Pathology

 

All tissues in foot abnormal

- bony / muscle / ST / vascular

 

Bony deformities

 

Talus 

- primary deformity

- equinus

- medial deviation of head and neck of talus

- external rotation of body of talus in mortise

- narrow neck & hypoplastic head due to lack of development of articular cartilage on lateral surface of head

 

Os Calcis 

- equinus

- medial rotation 

- long axes of talus & os calcis are parallel in sagittal & transverse planes

 

Navicular 

- subluxed medially against medial malleolus

 

Cuboid 

- medial column subluxed medially and adducted

- lateral & medial columns conjoined therefore cuboid subluxed medially also

 

Metatarsals 

- adductus but minor compared to talonavicular deformity

 

Soft Tissues 

 

Plantar fascia & intrinsics contracted

- long & short plantar ligaments

- contracture plantar fascia

- creates cavus

 

Tendons short

- T Achilles, T Posterior, FHL and FDL short

 

Ligaments short

- deltoid

- spring 

- calcaneofibular ligament

- posterior talofibular ligament

- bifurcate

 

Joint capsules contracted

- posterior ankle joint

- posterior subtalar joint

- talonavicular joint

- calcaneocuboid joint

 

Muscles atrophied

 

Classification

 

A.  Postural 

- passive correction possible

- usually corrects spontaneously within days / weeks

- well defined heel, no calf atrophy

- relatively normal foot size

- no transverse medial skin crease

 

Mild - nearly fully correctable

Moderate - partially correctable 

Severe - slightly correctable

 

B.  Rigid 

- uncorrectable

- small bean shaped foot, transverse crease, tight skin, atrophic calf

- heel difficult to palpate due to overlying fibrofatty tissue

 

C.  Teratogenic talipes 

- associated with spina bifida & arthrogryposis

- prognosis is much worse than idiopathic

 

Pirani Score

 

Pirani scoring system (0, 1/2, 1) (total out of 6)

 

Look (3)

- posterior crease / medial crease / lateral curvature

 

Feel (2)

- head of talus (anterior to lateral malleolus)

- empty heel

 

Move (1)

- DF range

 

Can be used to predict likelihood of needing TA tenotomy

 

Clinical Features

 

Look

 

Deformity / CAVES

Cavus - relative pronation of forefoot c.f. hindfoot

Adduction - forefoot

Varus - heel

Equinus - heel

Supination - midfoot

 

Posterior / medial crease

Curved lateral border of foot

Calf atrophy

 

Walk older child

 

Dynamic supination - require T anterior transfer

Metatarsus adductus

Foot progression angle - tibial torsion

 

ROM

 

DF

Eversion

 

Feel

 

Empty heel

Palpable talus - devils thumbprint anterior to lateral malleolus

Navicular fixed to medial malleolus

Os calcis fixed to the lateral malleolus

 

Exclude 

- spinal dysraphism - look at spine

- arthrogryposis

- neuromuscular disorders

 

Rotational Profile

 

X-ray

 

Usually not indicated

 

Ossification

- calcaneal & talus ossification centres are present at birth 

- cuboid appearing by 6 months

- navicular will not appear until 2-4 years 

 

Angles

 

AP talocalcaneal angle / Kite's angle

- ankle DF 15° & tube at 30° from vertical

- long axis talus parallel long axis of calcaneum

- normal 20-40°

- <20° hind foot in varus / clubfoot axes approach parallel

 

Lateral talocalcaneal angle

- long axis of talus parallel to long axis of calcaneum

- normal 25-50°

- < 25° indicates hindfoot in equinus

- clubfoot axes are parallel or negative

 

Talo-1st metatarsal angle / AP

- long axis of talus to long axis of 1st metatarsal

- normal 5-15° abduction

- clubfoot 0° to negative