Lecture 7: Orthotics

Question 1

Purpose of orthotics

Answer 1

Control abnormal compensatory movements of the foot by bringing the foot to the floor

Question 2

Goal of orthotic? How (what position)?

Answer 2

-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

Question 3

What happens during IC (heel strike)?

Answer 3

subtalar shock absorber

Question 4

What happens in mid stance?

Answer 4

Loading response moves into full pronation

Question 5

What happens in terminal stance?

Answer 5

Move into supination and becomes rigid

Question 6

In closed chain, what type of kinetic problems can over pronation cause?

Answer 6

-anterior pelvic tilt
-IR femur
-valgus knee
-medial rotation of fibula and tibia
-medial rotation, ADD, and PF talus
-calcaneal EV

Question 7

In closed chain, over supination can cause?

Answer 7

-posterior pelvic tilt
-femur ER
-knee varus
-lateral rotation of tibia and fibula
-ABD, DF talus
-calcaneal INV

Question 8

What biomechanical variable is associated w/ knee OA? What happens during this?

Answer 8

-Knee ADD moment (KAM)
-leg goes into varus during gait -> compressive forces to medial compartment of knee

Question 9

How much WB force passes through medial knee during KAM?

Answer 9

60-70% WB forces

Question 10

4 types of foot orthoses

Answer 10

Heel cup, heel lift, wedge, cushion

Question 11

What is the overall function of orthotics? Describe the two types (type of device and what it does)

Answer 11

Stabilization
-static: rigid device, supports body segment in fixed position
-mobile: permits body segment motion
-combo

Question 12

What are the 5 principles for orthotics

Answer 12

-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

Question 13

Describe the purposes and types of inside shoe or insert orthosis

Answer 13

-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

Question 14

Appropriately designed ____________ __________ can be very effective at reducing the _________ ______________

Answer 14

Valgus-wedged insoles/orthoses
External KAM

Reduces medial loading forces -> reduces medial knee pain in pts w/ mild to moderate medial compartment OA

Question 15

What two major pathologies do foot orthosis help treat?

Answer 15

Plantar fasciitis and posterior tibial tendon dysfunction

Question 16

What is the best use for UCBL? What else can it help w/?

Answer 16

Significant pronation; navicular dropping
Significant calcaneal eversion and mid foot support

Question 17

What is the navicular drop test?

Answer 17

Quantifies how much foot pronation someone has
10 mm is positive for over pronation

Question 18

Disadvantages of solid AFO

Answer 18

-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

Question 19

Reasons AFO are prescribed

Answer 19

-weakness
-stroke
-cerebral palsy
-head injury
-peripheral neuropathy
-alignment
-SC injury
-progressive disease

Question 20

What principles are used in orthosis? What 2 things make an orthosis most comfortable and effective?

Answer 20

-force principles
-pressure = force/area
-control direction of primary force and direction of counterforces

Question 21

Mass manufactured orthosis, off the shelf (describe, problematic)

Answer 21

-prefabricated orthoses available in wide spectrum of orthotic designs, shoe size, # of different materials
-foot deformity, sensory impairments