Lecture 7: Orthotics Flashcards
Purpose of orthotics
Control abnormal compensatory movements of the foot by bringing the foot to the floor
Goal of orthotic? How (what position)?
-Create a biomechanical balanced kinetic chain
-Controls/reduces pathological motion in the foot and leg by maintaining foot in or close to subtalar neutral position
What happens during IC (heel strike)?
subtalar shock absorber
What happens in mid stance?
Loading response moves into full pronation
What happens in terminal stance?
Move into supination and becomes rigid
In closed chain, what type of kinetic problems can over pronation cause?
-anterior pelvic tilt
-IR femur
-valgus knee
-medial rotation of fibula and tibia
-medial rotation, ADD, and PF talus
-calcaneal EV
In closed chain, over supination can cause?
-posterior pelvic tilt
-femur ER
-knee varus
-lateral rotation of tibia and fibula
-ABD, DF talus
-calcaneal INV
What biomechanical variable is associated w/ knee OA? What happens during this?
-Knee ADD moment (KAM)
-leg goes into varus during gait -> compressive forces to medial compartment of knee
How much WB force passes through medial knee during KAM?
60-70% WB forces
4 types of foot orthoses
Heel cup, heel lift, wedge, cushion
What is the overall function of orthotics? Describe the two types (type of device and what it does)
Stabilization
-static: rigid device, supports body segment in fixed position
-mobile: permits body segment motion
-combo
What are the 5 principles for orthotics
-pt related (easy to don on and off)
-soft tissue (doesn’t break down skin)
-at risk dx (diabetics, neuropathy)
-tolerant to compression and shear forces
-functional level of pt
Describe the purposes and types of inside shoe or insert orthosis
-modify heel, mid foot or forefoot
-padding for pain (plantar fasciitis, metatarsalgia)
-heel lift for leg length
-wedges for sup/pro
-heel cup for calcaneus to help instability
-longitudinal arch support
-UCBL
Appropriately designed ____________ __________ can be very effective at reducing the _________ ______________
Valgus-wedged insoles/orthoses
External KAM
Reduces medial loading forces -> reduces medial knee pain in pts w/ mild to moderate medial compartment OA
What two major pathologies do foot orthosis help treat?
Plantar fasciitis and posterior tibial tendon dysfunction
What is the best use for UCBL? What else can it help w/?
Significant pronation; navicular dropping
Significant calcaneal eversion and mid foot support
What is the navicular drop test?
Quantifies how much foot pronation someone has
10 mm is positive for over pronation
Disadvantages of solid AFO
-3 rocker phases (especially if set in a few degrees of DF to minimize knee hypertext)
-tibial advancement may be limited b/c it advances on a stable planted foot
Reasons AFO are prescribed
-weakness
-stroke
-cerebral palsy
-head injury
-peripheral neuropathy
-alignment
-SC injury
-progressive disease
What principles are used in orthosis? What 2 things make an orthosis most comfortable and effective?
-force principles
-pressure = force/area
-control direction of primary force and direction of counterforces
Mass manufactured orthosis, off the shelf (describe, problematic)
-prefabricated orthoses available in wide spectrum of orthotic designs, shoe size, # of different materials
-foot deformity, sensory impairments
