forefoot adduction

Metatarsus adductus

definition

· adduction of the forefoot at the tarsometatarsal joint

· intrauterine positional deformity

epidemiology

· incidence of 1 in 1000 live births

· equal sex incidence

· bilateral in 50%

· may be associated with CDH (10%)

aetiology

· unclear

· may be anomalous insertion of tibialis posterior more anteriorly

clinical features

· usually noted in 1st 3 months

· forefoot adducted and slightly supinated

· deformity usually fully correctable

· lateral border of foot convex

· prominent base of 1st metatarsal

· 1st and 2nd toes widely separated

· heel may be in slight valgus

· may be internal tibial torsion

· intoed gait

classification

Grade 1

· actively able to correct deformity

Grade 2

· deformity passively correctable

Grade 3

· unable to passively correct deformity
associated with medial plantar skin crease

radiology

· x-rays not routinely required

· if obtained, confirm forefoot adduction at tarsometatarsal joint

treatment

Natural history

· 85% resolve by age 3 yrs

Nonoperative

Under age 6 mths

· observation only

Over age 6 mths

· if deformity rigid, can use serial casting

· for 8-12 weeks

· changed every 2-3 weeks

Operative

· usually not indicated because

· deformity causes little or no disability

· complications from operative correction common

Early

· age 3 yrs with rigid deformity of at least 30^o

· explore tibialis posterior insertion

· if anomalous

· transfer of tibialis posterior tendon into navicular

· capsulotomy of naviculocuneiform joint

· if not anomalous or correction not achieved

· capsulotomies of all tarsometatarsal joints

Late

· age 6 yrs with persisting rigid deformity

· consider multiple metatarsal osteotomies

Skew foot

· uncommon foot deformity

· composed of

· tarsometatarsal adduction

· tarsonavicular lateral subluxation

· hindfoot valgus

· similar treatment to metatarsus adductus

· may need triple arthrodesis as salvage