· increased longitudinal arch of foot
· deformity characterised by
· plantarflexion of first ray
· supination of forefoot
· hindfoot varus
· clawing of toes
· forefoot adduction
· 2/3 due to neurological disorder
· spinal dysraphism
· spinal cord tumour
· spinocerebellar degeneration (esp. Friedrich’s ataxia)
· hereditary neuropathy (esp. Charcot-Marie-Tooth disease)
· poliomyelitis
· cerebral palsy
· hydrocephalus
· may be more than one pattern of muscle imbalance
· common pattern has
· tightness of posterior structures
· weakness of tibialis anterior
· secondary dorsiflexors (EHL and EDL) assist in dorsiflexion of foot
· results in hyperextension of MP joints
· windlass mechanism leads to dropping of metatarsals
· most marked in 1st MT
· initially involves dropping of 1st ray
· naviculo-1st cuneiform and cuneiform-1st MT joints become rigid
· other metatarsals remain mobile until late
· entire forefoot is everted (supinated)
· fascia placed in shortened position
· gradual contracture occurs
· continuing contracture increases cavus deformity
· to place lesser MT heads on floor, heel has to invert
· at first, only occurs on weight bearing
· later becomes rigid
· because of overactivity of EDL
· initially is reducible on dorsiflexion of foot
· later MTP jts sublux and deformity becomes fixed
· recurrent lateral ankle sprains
· shoe fitting and wear problems
· callosities under metatarsal heads
· callosities over dorsal PIP jts
· elevated medial longitudinal arch
· plantarflexion of 1st metatarsal
· variable amount of
· heel varus
· clawing of toes
· deformities become rigid with time
· heel varus initially correctable
· subtalar joint then becomes stiff
· flexible cavus foot
· corrects with pressure on 1st MT
· equinus of 1st MT irreducible
· hindfoot equinus flexible
· lesser MTs participate in rigid equinus
· hindfoot equinus rigid
· deformity more severe
· bony structural changes
· standing films
· talus and calcaneus nearly parallel
· sinus tarsi visible clearly
· increased Meary’s angle
· line along long axis of talus
· line along long axis of 1st MT
· measure angle between them (Meary’s angle)
· should be 0o but increased in pes cavus
· metatarsals widely convergent from bases to heads
· MTP jts hyperextended
· talus and calcaneus almost superimposed
Forefoot
· assess whether 1st MT in fixed flexion
· push on head of 1st MT
· if flexible, tarsometatarsal joint dorsiflexes to neutral
Hindfoot
· if 1st MT in fixed flexion, hindfoot thrown into varus on weight-bearing
· use Coleman block test to evaluate flexibility
· place block (1.5”) under lateral border of foot
· negates fixed flexion of 1st MT
· if heel varus corrects, hindfoot flexible
· should perform careful neurological examination
· should obtain neurological consultation
Spine
· cutaneous features to suggest spinal dysraphism
· hyperpigmented midline lesions
· dimples
· hairy patches
· lipomas
Muscles
· careful grading of muscle power around foot
· required if tendon transfer contemplated
Investigations
· plain AP spine x-ray should be performed
· look for
· interpedicular widening
· congenital vertebral anomaly
· spina bifida occulta
· diastomatomyelia
· other investigations may be warranted
· myelogram or MRI of spine
· CT or MRI of brain
· nerve conduction studies
· peripheral nerve or muscle biopsy
· nonoperative in the form of
· shoe modifications and orthoses
· manipulation and exercises
· will not affect progression
· will alleviate symptoms
Principles
· in 2 stages
· 1st stage consists of
· plantar release (Steindler stripping)
· correction of 1st MT drop if still required
· 1st MT drop may be corrected with
· osteotomy of base *
· Jones tenosuspension
· 2nd stage performed after 6 weeks
· in form of tendon transfers to prevent recurrence of deformity
Techniques
Steindler stripping
· medial approach
· release from calcaneus of
· plantar fascia
· abductor hallucis
· flexor digitorum brevis
· abductor digiti quinti
· plantar fascia
· long plantar ligament
· forefoot deformity forcefully corrected and held in plaster
· may require capsulotomies of midtarsal and tarsometatarsal joints
First metatarsal osteotomy
· dorsal closing wedge just distal to physis
· internally fixed with pin or screw
Jones tenosuspension
· EHL divided 2 cm from IP jt
· distal stump sutured to proximal phalanx
· through vertical drillhole
· proximal stump sutured to distal metatarsal
· through transverse drillhole
· MT held in forced dorsiflexion
Tendon transfers
· tendon transfers must be tailored to deformity
· loss of tibialis anterior function most common
· esp. Charcot-Marie-Tooth disease
· treated with transfer of tibialis posterior through interosseous membrane
Principles
· plantar release performed
· forefoot equinus fixed with Hibb’s procedure
· transfer of long extensors to metatarsals
· removes deforming force which hyperextends MTP jts
· uses force to supplement dorsiflexion
· hindfoot varus fixed 6 weeks later with sliding calcaneal osteotomy
Techniques
Extensor transfer
· Jones transfer performed
· extensor tendons of lesser toes exposed
· tendons of 2nd and 3rd toes sutured to 3rd MT
· through transverse drillhole in proximal shaft
· tendons of 4th and 5th toes sutured to 5th MT
Calcaneal osteotomy
· osteotomy in body of talus in transverse plane
· shifted laterally
Principles
· as above but forefoot equinus corrected with osteotomy
Techniques
Japas tarsal osteotomy
· V-shaped osteotomy
· apex in navicular
· limbs extending distally
· laterally through cuboid
· medially through 1st cuneiform
Cole tarsal osteotomy
· vertically orientated wedge excision osteotomy
· proximal osteotomy through navicular and cuboid
· distal osteotomy through cuneiforms and cuboid
· deformity characterised by
· dorsiflexion of calcaneus
· plantarflexion of forefoot
· weakness of triceps surae
· due to
· polio (most common worldwide)
· cerebral palsy
· myelodysplasia
· spinocerebellar degeneration
· post-traumatic fibrosis of deep posterior compartment
· because of weakness of triceps surae, calcaneus assumes dorsiflexed position
· insertion of tendo Achilles moves anteriorly
· further weakens lever arm of calcaneus
· result is elevated longitudinal arch
· forefoot becomes flexed because of
· gravity
· action of muscles during gait
· difficulty walking
· evaluation of obvious deformity
· shoe fitting and wear problems
· painful callosities
· elevated longitudinal arch
· prominent heel with abundant callus on plantar aspect
· called pistol grip deformity
· usually claw toes
· heel usually in neutral
· lateral x-ray of foot
· dorsiflexion of calcaneus
· if heel valgus present, x-ray of ankle joint
· to look for valgus of tibial plafond
· of neurological cause as above
· modification of shoe wear and orthoses required
· cannot control deformity alone
Age < 5 yrs
· no surgery
· no significant deformity
· muscle testing difficult
· disability unlikely
· exception is spina bifida
· transfer of tendon of triceps surae to fibula
· to prevent valgus deformity of tibial plafond
· stimulates fibular growth
Age 5-12 yrs
1st stage
1. stabilisation of subtalar joint
· extraarticular arthodesis
2. transfer of tendo Achilles to fibula
· if associated valgus deformity of tibial plafond
2nd stage
1. release of plantar structures
· through medial incision
2. calcaneal osteotomy
· if calcaneus severely deformed
· cresentic osteoteotomy in coronal plane
· posterior and superior displacement of posterior fragment
3. tendon transfers
· to improve plantarflexion
· muscles in phase preferable (ie. tibialis posterior and peroneals)
· fix tendons to apophysis of calcaneus to stimulate growth
Age > 12 yrs
· fixed bony deformity
1st stage
1. chevron osteotomy of tibia
· if valgus deformity of ankle exists
2nd stage
1. release of plantar structures
2. triple arthrodesis
3. tendon transfers
Flail foot
· tendon transfer not possible
· orthoses until age 12
· then
· soft tissue release
· panatalar arthrodesis
· third type of clubfoot
· similar to cavovarus foot