Rod Hammett Consultant Orthopaedic Surgeon Musgrove Park Hospital

What patients does the surgeon want to see?

What patients does the neurologist want the surgeon to see??

What does the surgeon need to know???

What does the patient want????

“CMT commonly presents to orthopaedic surgeons with lower and upper limb symptoms including ankle sprains, cavus feet, and weakness of intrinsic hand muscles. More rarely, they present with spinal and hip manifestations. It is not usually a life threatening or painful condition and therefore lends itself to the FRCS (Tr & Orth) exam.”

Ankle and hindfoot

Instability, recurrent sprains

Peroneal tendon pain

Insertional Achilles problems/plantar fasciopathy

Secondary degenerative joint disease

Tibial stress syndrome

Knee pain/genu varum/ITB syn

Mid and Forefoot 5th metatarsal

▪ Fracture(s)

▪ Non union

▪ Basal overload

Metatarsalgia

Midfoot OA

Claw toes

Neuropathic ulceration

Shoe breakdown

Diffuse/ multiple complaints

Any combination of the above

Beware pain fibre neuropathy

Neuromuscular until otherwise proven

Neuromuscular

Peripheral neuropathy CMT (HMSN)

Spinal Cord Disease Poliomyelitis/ neoplasia /syringomyelia

CNS disease Freidrich’s ataxia, cerebral palsy

Myopathy Muscular dystrophy Congenital

Arthrogryposis

Residual Club Foot deformity Trauma

Post compartment syndrome

Peroneal nerve palsy Idiopathic

70% have neurological diagnosis

CMT (HMSN) 50% of patients

30% Idiopathic

Importance of full neurological assessment Especially ▪ FH, bilateral, gait impairment / muscle atrophy

▪ Sensory / motor disturbance

Described 1886

Spectrum of genetic disorders that affects peripheral nerves

Slows action potential transmission or amplitude

Usually present with

Lower limb

▪ Cavus feet / ankle sprains

Upper limb

▪ Intrinsic weakness

Strong genetic component FH (spontaneous genetic mutation) Lots of subtypes of CMT

Inheritance pattern

What part of nerve cell is affected

Genes affect nerve proteins Progressive disease Management

Maintain mobility and independence

Lower limb pain 90% Rubbing toes 60% Metatarsalgia 50% Ankle instability 30% Lateral border pain 10% Ankle/hindfoot pain 10% Ulceration 1%

Pes cavus

Latin “hole / pit”

“hollow foot”

“A foot with a high arch that fails to flatten with

weight bearing”

Prevalence 10%

Cavovarus (HSMN)

Forefoot plantarflexed

Hindfoot varus

(1st ray > others – pronated)

Calcaneocavus (POLIO)

Dorsiflexion of calcaneus

Fixed equinus of forefoot

No pronation of forefoot – therefore no varus deformity

Plantaris

Plantarflexion of forefoot

Calcaneus

Dorsiflexion of hindfoot

Cavovarus

Varus deformity of hindfoot

Cavus

Equino –Cavo-Varus

Calcaneo-Cavo -Varus

A – Meary’s Angle N = 0 – 5 Degrees B – Calcaneal Pitch Angle N = 30 degrees C – Hibbs Angle N = <45 degrees D – Weight Bearing Tibioplantar Angle N = 90 degrees

Peroneus longus (1st MT and adj cuneiform)

Plantarflexion first ray / evertor

Tibialis anterior (1st MT and adj cuneiform)

Dorsiflexion

Peroneus Brevis (5th MT)

Evertor

Tibialis posterior (Navicular tuberosity)

Invertor / Flexor

Intrinsics

Flex the MTP / extend IP

Posterior muscles normal

Anterior weak (variable)

Weak Tib Ant – Relatively strong Peroneus Longus Forefoot equinus

Peronus Brevis weak / Tib Post normal Hindfoot varus

Hypothesis

Normal anatomy and function

Intrinsic and extrinsic muscle balance

▪ Acting on normal soft tissues and bones / joints

Muscular imbalance

Deformity and impaired function

Disorder differentially affects extrinsic muscles

CONTROVERSIAL

Tib post >peroneus brevis

▪ Adduction of forefoot and inversion of hindfoot

Peroneus longus > Tib ant

▪ Plantar flexion of first metatarsal

Tib ant weak – EHL and EDL aid dorsiflexion

▪ MTP dorsiflexion Tib ant> gastrocnemius / soleus (Polio)

Disorder affects foot Intrinsic muscles

CONTROVERSIAL

(Deformity can pre-date extrinsic weakness + MRI findings)

Long extensors - Dorsiflexion of MTP

Long flexors – IP joint flexion

Intrinsic shortening + windlass - Plantar aponeurosis tensioned - shortening of medial longitudinal arch

Cavus can progress without clawing!

Theory 1 and 2 are correct

Probably not a single problem in all cavus feet

“Windlass effect”

Plantar plates of MTP attached to plantar fascia

MTP extension tightens plantar fascia

Increase arch - cavus

Medial band largest – medial calcaneus - varus

“Tripod effect” Heel, 1st MT head, 5th MT

head

Plantigrade / no varus or valgus

1st ray plantarflexed ▪ 3 points can only rest on

ground if heel – varus

▪ (Coleman 1977 – “block test”)

“Plunger effect” (Stainsby)

MTP extension forces MT heads plantarward

MT plantarflexion

Bony Deformity

Bone growth affected by deforming forces

Altered bone shape

Variable Toes

PIP rubbing / tips of claw toes

Metatarsal Heads

Metatarsalgia

Hindfoot varus

Ankle instability (peroneus brevis)

Lateral foot pain

Stiff hindfoot

▪ Unable to absorb forces

▪ Fatigue

▪ Ankle / hindfoot pain

General

Shoe fitting /wear

Non specific foot pain (50% of CMT – not responsive to surgical measures)

Weakness

Ulceration

Most autosomal

dominant Demyelination of

nerves Presents in second

decade Diagnosed by

decreased nerve conduction velocities

Weakness Ataxia Distal sensory loss Areflexia Equinus/Calcaneus Cavus Varus

Autosomal Dominant

Neuronal form

Later presentation

Mildly Impaired Nerve Conduction Velocities

Onset in 20s and 30s

Profound limb weakness

As Type I or Stork leg appearance

Flail foot

Calcaneo varus or Flat foot

Autosomal recessive Includes Dejerine

Scottas syndrome (hypertrophic neuropathy of infancy)

Presents in infants Demyelination with

decreased conduction

Sensory loss (Glove and stocking)

Muscle weakness and contracture

Spinal deformity common

Type IV – Refsum disease Type V - Inherited spastic paraplegia

with distal weakness Type VI - Peroneal muscular atrophy with

optic atrophy Type VII – Atrophic muscle weakness with

retinitis pigmentosa

Explanation

Reassurance

Natural history & inheritance

Neurology/Genetics

Orthoses Insoles ▪ Metatarsalgia, accomodative, FFO

▪ Total contact insole

Shoes ▪ Lateral wedge & flare

▪ Extra depth toebox

AFO, ankle brace, caliper

Put the Foot below the leg Put the Foot square to the ground BALANCE THE MUSCLE POWERS

À la carte approach

Stepwise correction starting proximally and working distally

Balance the forces to maintain bony correction (even with fusions)

Flexible deformities – tendon transfers +/- axial realignment

Fixed deformities – osteotomies and soft tissue releases

Degenerative joint disease – arthrodesis (or replacement)

Patients with Charcot Marie Tooth have neuropathic pain

Surgery may introduce or exacerbate pain

Treat structural problems, not pain

After Surgery Change the shoes!

Careful examination and weightbearing XR

Supramalleolar osteotomy?

Achilles lengthening

Avoid over lengthening

Isolated gastroc?

ATFL reconstruction

Peroneal tendons

Brevis to longus tenodesis

Corrects calcaneal pitch

Not for plantaris correction

Beware medial and lateral plantar nerves

Chevron or ‘Z’ Correction of

calcaneus deformity Minimally invasive

surgery possible

Stiff subtalar/Chopart

Symptomatic DJD

Paralytic deformity

Peroneal LMN

polio

Calcaneal osteotomy

1st MT osteotomy

Gastroc/ Achilles release

Tendon transfers

Soft tissue releases

Adjunct procedures Talectomy

Wedge resections

Frame

Severe cavus

Dorsal bump

Foot realignment

Ankle fusion

TTC/ pantalar fusion

Ankle replacement

Foot realignment

Ankle fusion

TTC/ pantalar fusion

Ankle replacement?

Foot realignment

Ankle fusion

TTC/ pantalar fusion

Ankle replacement

Three components

Cavus

Adductus

Pronation

First ray Composite midfoot (wedge) osteotomies Triple fusion – Chopart’s joints correct

pronation

Coleman block test

Correctable hindfoot driven by 1st MT plantarflexion

Plunger effect

Windlass effect

Peroneus longus> tibialis anterior

Secondary fixed contracture

Treat claw hallux Transfer EHL

MT neck > tib ant>lateral

Elevate 1st MT dorsal closing wedge

TMT fusion

Longus to brevis transfer?

Plan from Coleman

block test

Restore dynamic balance for correctable deformities

Prevent recurrence after osteotomy or arthrodesis

Tibialis posterior and triceps surae

overpower

Tibialis anterior and

peroneus brevis

Invertors and flexors

overpower

Extensors and evertors

Tibialis posterior

Peroneus longus to brevis

Tibialis anterior laterally

Jones procedure

Mallet Hammer Claw

PF Flexors & intrinsics

PF Flexors

Dorsal callus

Dorsal ulceration

Nail walking and tip callous

“Plunger” effect

metatarsalgia

Type 1 Flexible MTP and IPJ Rarely present

Type 2

Stiff IPJ flexible MTP (+/- subluxation)

Type 3 Stiff IPJ &MTP

Type 1

FETT

MTP capsulotomy

PIP arthroplasty

Type 2

PIP fusion/arthroplasty +/- MTP release

Type 3

PIP fusion/arthroplasty +/- radical MTP release

& Kwire Or Stainsby

hemiphalangectomy

Flexible

Rarely present

FHL transfer to P1

Stiff

Jones procedure

IPJ fusion

EHL transfer to MT

History

Establish patient’s problem

Treat the patient not x-ray

Simple non-operative Mx first

Forefoot balancing if forefoot driven

Osteotomy and tendon transfer for mobile hindfoot joints

Fusion for fixed deformities/OA/paralysis