Biomechanics pes cavus

pod2ndyear's version from 2015-07-18 20:46

pes cavus intro/ Xray differentiaion

Question Answer
What plane are pes cavus deformities insagittal plane but are rarely isolated sagittal plane
pes cavus may functionpronated or supinated
common mistake with pes cavusequating it to a supinated foot
A FF varus with cavus will compensate withpronation (therefore this may be a high arched, pronated foot type)
Xray SUPINATED foot lateral viewincreased calcaneal inclination angle
decreased talar declination angle
posterior displaced cyma line
plantar deviation of meary's line
increased stair step effect on met
bullet hoe sinus taris
Xray SUPINATED DP viewFF adducted on rearfoot
decreased talocalcaneal angle
increased forefoot/met overlap
Xray HIGH ARCHED foot w/out supination lateral viewincreased calcaneal inclination angle
decreased talar declination angle
normal meary's line
normal cyma line
normal met relationship
Xray HIGH ARCHED foot w/out supination DP viewno FF or met adduction
normal talocaneal angle
normal met relationship

pes cavus types/classification-location of deformity

Question Answer
name the types of pes cavus based on locationanterior cavus (met, lesser tarsus, FF), posterior cavus, combined/global cavus
describe metatarsus cavusLizfrancs joint it apex
dorsal prom at 1st MTC jt
talus navicular and cuniforms are colinear
symptoms of metatarsus cavushigh instep
1st MTC exostois
difficult shoe fit
normal cuboid anglulation
pseudoequinus may lead to pronation
claw toe
describe lesser tarsus cavusPF lesser tarsal bones
dorsal prom in lesser tarsal area
(variant: plantarflexed 1st ray)
describe FF cavusFF is PF at choparts jt
RF appears to be DFed,
dorsal prom talar head immediately anterior to MM
navicular, cuboid, 4th and 5th met are PFed compared to RF
symptoms of FF cavuscalcaneal apopysitis in children
claw toe
FF cavus variantsPFed cuboid, 4th and 5th met (anteriorly displaced cyma line)
combined anterior cavus (FF is PFed in 2+ areas-tarsalmetatarsal, lesser tarsal, choparts)
describe posterior cavusrare due to untreated Achilles rupture
increased calcaneal pitch
combined/global cavusrarest, both anterior and posterior cavus present
pes cavus structural deformitiesnot associated with MTJ sup comp
pes cavus aquired and congenitalare not structural, not limited to sagittal plane deformity, associated with MTJ sup

Pes cavus based on etiology

Question Answer
Congenital etioneurogenic
(spinal cord, nerve degenerative disease, dejerine-sottas, CP, muscluar dystrophy, congenital syphilis, tailpes equinovarus (clubfoot),
Infectious etiopoliomyelitis
neoplastic etiobenign and malignant tumors pressing on lumbar-sacral n. roots
neurogenic etiononcongenital neurological disease
traumatic etiohead or isolated n injuries
biomechanical etioPFed 1st ray
uncompensated RF varus
Rigid FF valgus
Iatrogenic etioprolonged bed rest
overcorected flatfoot surgery
Endocrine etioDiabetes mellitus-intrinsic m weakness
Muscle imbalance etiodue to neurological deficit
spasticity and true weakness
Spasticity typestonic, clonic
tonic spasticityincreased tone in m belly due to guarding (may exibit a cogwheel release)
clonic spasticiyassociated with upper motor neuron deficit
resistance may gradually relax with manual pressure
posterior weaknesstriceps-decreased pull on calc leads to increased calc angle, substitution by deep post group may lead to STJ sup and digital deform.
tricepts spaticity-lead to toe walking.
tibialis posterior spasticty-may lead to constant and increased sup at the STJ
anterior wekanessglobal anterior weakness-overpowering deep flexors, leads to both ankle and FF equinus isolated muscle weakness
lateral PL spastictyincreased PFory pull on first ray
Intrinsic weakness or spastictydigits become dorsally contacted
mets become PFed resulting in cavus

compensation for pes cavus

Question Answer
4 changes will occurdorsal contraction of digits (clawfoot), met PFion, relative DFion of FF on the RF due to GRF , pseudoequinus
Coleman block testto tell if the RF is fixed or flexible (a result of a FF deformity)
pt stand on a block with FF haning off edge.
reduced RF=flexible (a result of FF deformity) .
nonreduced RF=fixed
coleman block test is more commonly used to determinewhether or not an inverted RF is as a result of PFed first ray
treatmentcan give one specifit treatment
shoe mod
surgical procedures
surgical proceduresfusions
m/ten surgiers to transfer/realign pull
tendon transfer1/2 to 1 full m grade will be lost, tendon may or may no be transfered "in phase"
orthotic modwith claw toe FF extensions to pad the met heads
what instabillity is associated with pes cavuslateral ankle (use a lateral flange, heel or flare)
cavus foot tripod weightheel, 1st 4th/5th metheads, orthoses can help distribute the weight.

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