Orthodics Flashcards
biomechanical balance kinetic chain
subtalar neutral position
- allows the foot to be mobile in pronation and stiff in supination
- 0 degrees in ankle, subtalar neutral, balanced forefoot
what is the rear foot and its joints
calcaneus
1) talocrural joint
2) subtalar joint
what is the forefoot and its joints
the center of pressure through the first ray
1) 1st metatarsal phalangeal joint
the mid foot at its joints
1) Tarsometarsal joint
2) calcaneocuboid joint
3) Talonavicular joint
subtalars job at inital contact
shock absorber (pronation)
subtalars job at midstance
still shock absorption. LR moves the foot into full pronation
subtalars job at terminal stance
moves into full supination for rigidity
kinetic problems with closed chain over pronation
- anterior pelvic tilt
- internal rotation of the femur
- valgus knee
- internal rotation of the tibia and fibula
pronation in the subtalar joint
- medial rotation of the talus
- adduction and PF talus
- calcaneal eversion
kinetic problems with closed chain supination
- posterior pelvic tilt
- femur external rotation
- knee varus
- external rotation of the tibia and fibula
supintation of the subtalar joint
-abduction and DF talus
- calcaneal inversion
KAM (knee adduction moment)
- moment of compressive forces across the medial knee
- most force at LR and terminal stance
- accepts 60-70 % of weight bearing forces throughout this compartment
the relationship between knee varus and KAM
knee varus increases KAM. It is a direct relationship
static stabilization
rigid device, permits body segment in fixed position (stability)
dynamic stabilization
mobile device, permits the body segment motion
principles of designing orthotic function
- patient related (easy to don on and off)
- soft tissue: not break down skin
- at risk diagnosis (diabetics, neuropathy)
- tolerant to compression and shear forces
- functional level of the pt
Insoles purpose
- modify heel, midfoot or forefoot
- padding for pain (metatarsalgia, planterfasciitis)
- heel lift for leg length
- wedges for supination/pronation
Instability orthotics purpose
- have heel cup for calcaneous
- longitudinal arch support
- UCBL
what orthodic can be used to help reduce KAM
- valgus wedged insoles on the medial side of the foot
UCBL purpose
- used for pronated foot
- holds the calcaneus in a neutral position
- used for significant issues such as arthritis, hypotonia
- helps prevent midfoot collapse into pronation
the higher the trim lines the
better control of the calcaneus
what can a leaf spring AFO be used for
people who are having foot drop during swing phase
what would you prescribe for ankle instability in stance phase
solid or hinged AFO
what would you prescribe for ankle planter flexion
solid AFO with strap
what would you prescribe for knee hyperextension in stance phase
AFO setting ankle joint to neutral or a bit of DF
AFO adaptations to trimlines
allow for more or less control of the ankle
what are the different trimlines
- metatarsal trimline
- foot trimline
- ankle trimline
- standard trimline
- anterior trimline
- proximal trimline
what pathologies are AFOs typically prescribed for
- weakness
- CP
- head injury
- peripheral neuropathy
- alignment
- SCI
- progressive disease
what do orthotics use to accomplish the goals of its design
force principles
an orthotic is most comfortable and effective when
1) pressure = force/area
2) control direction of primary force and direction of counter forces
off the shelf orthotics
- mass manufactured
- the degree to which they can be modifies or adjusted to fit an individual varies (this can be problematic for people with foot deformity, wide or narrow feet, large calf muscles, sensory impairments or variable limb volume
examples of off the shelf orthotics
- standard AFO
- Leaf Spring AFO
Leaf spring AFO design
- shallow trim lines for less support and more mobility
- no other straps to control or brace the foot
- foot plate
purpose of leaf spring AFO
- support the weight of the foot during swing phase as means of enhancing swing limb clearance
- assist with controlled lowering of the foot during loading response in stance as part of the first heel rocker
what type of pt would you prescribe leaf spring too
peripheral nerve, multiple sclerosis, CVA, myositis pt with foot drop in swing
what type of patient is leaf spring NOT good for
CP pts
other AFOs for foot drop
- posterior shell
- DF assist brace: stiffness with energy storage within shell enhances PF power
Solid AFOs design
- larger trim lines allow for more control of the tibia
- support for the calcaneus
- wider control of the footplate: prevents excessive eversion and inversion
purpose of solid AFO
- to resist PF during swing phase
- fulcrum force applied to the anterior ankle by velcro strap
- made form thick thermoplastic
- hold the ankle in a biomechanically neutral position
- might have medial and lateral corrugations incorporated within
what type of pt are solid AFOs prescribed for
pt with spatisity
- tone-inhibition bar if hypertincity is severe (metatarsal bar)
- people who are not responding to therapy and have no LR
static AFO (Solid AFO)
- aims to hold the foot in place. more stability less mobility
what are the disadvantages of solid AFOs
- does not support the heel rocking phases
- proximal anterior strap prevents tibia advancement and lack of eccentric control in LR
how do pts with solid AFO with anterior staps compensate for losing tibial advancement
by flexing their knee in midstance
