KnotesFree Orthopaedic & FRCS notes, viva stations and higher order SBAs

Pes Cavus

Must KnowFoot & AnklethinKbox SBA

Causes

  • Idiopathic

    • Clubfoot seqüela
  • Trauma

  • NM

    • CNS
      • CP
    • Spinal cord
      • Spin bifida
    • PNS
      • HSMN
    • Muscular
      • Dystrophy
  • B/L: CMT (most common)

  • T ant, Per brevis and intrinsic weakness

  • Unilateral: Spinal cord tumor until proven otherwise

CMT

  • AD, Cr 17
  • PMP 22 protein is affected
  • Recessive forms appear earlier and more severe

HSMN

Column 1 Column 2 Column 3 Column 4
CMT 1 CMT 2 Dejerine stotta
Inheritance AD AD AR
Age 10-20 20-30 Infant
Pathology Demylination Wallerian degn
Reflex Absent Present
NC/EMG Inc Latency; dec velocity EMG normal
Severity Less Less severe

Deformity: Mobile hind foot

  • Cavus
    • Plantar flexed 1st ray: Per Longus overpowers T ant
  • Varus
    • Plantar flexed 1st ray pronates the foot
    • This is compensated by varus due to tripod effect
  • Equinus
    • Weak Tant overpowered by GS
  • Claw toes
    • Intrinsic minus
    • recruitment of EHL and EDL due to weak T ant

History

  • Stiffness
  • Deformity
  • Recc sprains
  • Painful callosities due to clawing

Examination

  • Stand and look
    • Deformity
    • stock legs
    • Hand wasting
    • Coleman block test: to know the mobility of ST joint
  • Walk and look gait: broad based ataxic
  • Sit and look
    • Callosities
    • Clawing

Feel

  • Sensation
  • Pulse
  • Tenderness

Move

  • Is clawing flexible

Spl tests

  • Silverskeiold test
  • Muscle power:T Post, T Ant, P Long, P Brevis
  • Spine
  • Reflex

Investigation

  • X Ray wt bearing
    • increased pitch angle and meary angle
  • MRI
  • EMG
  • NCS

Management

  • Less symptomatic foot can be managed non surgically by accommodating foot wear, physiotherapy and stretching, but does not alter the course
  • Treatment for more symptomatic foot is surgical and the aim is plantigrade painless stable and mobile foot
  • Surgery has to be tailored to the underlying cause, deformity, patients symptoms and risk of progression due to muscle imbalance. Correction of deformity with out addressing the imbalance will not be successful

Surgery

  • Plantar flex 1st ray:
    • Dorsal closing wedge osteotomy
    • P long to braves transfer
  • Cavus
    • Plantar fascia release
  • Varus
    • Lateral closing wedge osteotomy calcaneus
  • Equinous
    • TA lengthen

Hind foot fixed

  • Triple arthrodesis

Clawing

  • Girdlestone FDL to EDL transfer
  • Weil osteotomy
  • PIP fusion and weil
  • MTPJ release and PIPJ excision
  • Big toe
    • Johns procedure: MTPJ arthrodesis and EHL to 1st MT

Written/reviewed by Kishore Puthezhath

Professor of Orthopaedics and Consultant Paediatric Orthopaedic Surgeon

FRCS (Tr & Orth) revision resource

Reviewed: September 2026