19_20- Orthotics

Question 1

Describe the windlass mechanism

Answer 1

Mechanism by which the plantar fascia acts like a tether between the hindfoot and forefoot. Dorsiflexion of the 1st MTP (like in toe-off) causes tensioning of the plantarfascia, allowing for a springing mechanism.

Question 2

Dorsiflexion of the great toe (supinates/pronates) the foot

Answer 2

Supinates

Question 3

What kind of pathological mechanism in the foot would you expect to see in an individual with genu varum?

Answer 3

Over-pronation - in order to get 1st met on ground

Question 4

External rotation of the femur and tibia are associated with:
A. Foot pronation
B. Foot supination

Answer 4

B

Question 5

Flexion (posterior tilt) of the pelvis is associated with:
A. Foot pronation
B. Foot supination

Answer 5

B

Question 6

What does it mean for someone to have a steep axis of rotation in the subtalar joint?

Answer 6

Most of the motion is in abduction/adduction plane, causing excessive internal and external rotation; because the tibia is’clamped’ around the talus (it has no other option than to follow it)

Associated with increased risk of injury with over-pronation

Question 7

Having a steep angle of inclination of the subtalar joint axis predisposes one to:
A. Knee pain
B. Foot pain
C. Hip pain
D. Toe pain

Answer 7

A

Question 8

How can you check for excessive tibial rotation in clinic?

Answer 8

One-legged squat test

Question 9

True or false: If the knee stays over top of the foot during a squat, the patient does not have a steepangle of inclination of the subtalar joint axis.

Answer 9

True

Question 10

What is the primary purpose of a flexible orthotic?

Answer 10

Intrinsic foot pain (usually for elderly patients)

Question 11

What can be added to an orthotic for individuals with Morton’s neuroma, dropped met head, or bunions?

Answer 11

Metatarsal pads

Question 12

What are vector cuts? What are they used for?

Answer 12

Cut medial portion of orthotic away so first met head sits on shoe

Useful for supinators and functional hallux limitus

Question 13

Which of the following additions to orthotics should be included in all cases if there is sufficient room in the patient’s shoes?
A. Arch fill
B. Heel spur pad
C. Extrinsic heel posts

Answer 13

C - helps avoid pronation and adds stability

Question 14

Which of the following is thought to be the primary way that orthotics exert their clinical effect?

A. Altering joint kinematics and therefore aligning the skeleton
B. Providing improved impact cushioning
C. Improving sensory feedback (proprioception)
D. Reduction of soft tissue vibration (altering muscle activation)
E. Altering the transfer of rotations up the kinetic chain

Answer 14

C and D

Question 15

It has been found that the frequency of heel strike forces is around the same range as the natural frequency of soft tissues (meaning that it should be massively amplified, causing widerspread vibration). How does the body avoid this? What effect does orthotics have on this?

Answer 15

Muscle contraction causes dampening of the vibration

Orthotics increase ST damping - reduces ST vibration

Question 16

Orthotics generally require a break in period. The first day the patient has the orthotics they should wear them for only one hour. Each day that time is doubled unless the patient had pain. If the patient wore them on the second day for two hours but had pain during the last portion of that time, the third day would also involve 2 hours of orthotic wear time.

True or false: Once they can make it through two hours with no symptoms, they can move on to 4 hours per day.

Answer 16

True - For most people, wear the orthotic for one hour the first day, and double the time eachday until they are wearing them all day

Question 17

How can you find “subtalar neutral” when casting someone for orthotics?

Answer 17

Make sure talus is of equal prominence on medial and lateral sides

Question 18

True or false: a patient should be standing when a foam cast is taken to make sure the cast is done in a weight-baring position

Answer 18

False - should be sitting with hips, knees, and ankle at 90deg. Practitioner then pushes heel into foam, and then uses thenar to push forefoot into foam ensuring equal depth of heel and forefoot