Exam 4: Orthotics Part 2, Foot Deformities, AFOs

Question 1

What are four common problems of the forefoot that might requiqre orthoses?

Answer 1

1. Metatarsalgia (pg 172)
2. Sigmoiditis
3. Morton’s Sydrome
4. Morton’s Neuroma

Question 2

Metatarsalgia:

• What is it?
• Caused by?
• Possible exacerbating factors? (3)
• Goals for helping with an orthosis: (3)

Answer 2

• Pain in the metatarsals
• caused by compression of nerves
• Possible contributors
  
  • tight shoes
  • high heels (compress area and then loads it with all weight)
  • atrophy of foot fat (natural cushion)
• Goals for help
  
  • cushioning
  • transfer weight bearing away from that area
  • Add space (change shoe, make sure it is wide enough)

Question 3

Sigmoiditis:

• what is it?
• Caused by? (2)
• Treatment goals (for orthosis or shoe modification)

Answer 3

• an inflammation around the sesamoid bones under the first metatarsal head.
• often results from a loss soft tissue padding under the first metatarsal head and from toe deforities such as hallux valgus and hallux rigidus.
  
  • repeated stress
  • diabetes
• Put cushion in there to redstribute weight
  
  • could use metatarsal bar
  • could use rocker bottom to prevent movement of first MTP joint if moving it is painful

Question 4

Morton’s Syndrome:

• What is it?
• Treatment goals (for orthoses or shoe modification) (3)
• Problems with treatment (2)

Answer 4

Repetative irritation of the plantar digital nerve between the first and second interspace (between the first and second metatarsal heads)

• A neuroma is likely to develop

Three major objectives for treatment

• redistribute weight (unweight it)
• stablize the rearfoot by maintaing subtalar joint neutral
• accomodate forefoot varus as well as possibly dorsiflexed first metatarsal

problems

• might change mechanics
• might put too much pressure elsewhere

Question 5

Morton’s Neuroma

• what is it?
• Treatment goals (5)
• Problems with treatment (2)
• Alternative treatment

Answer 5

Overstretching of the digital nerves in extreme toe extension at the proximal phalanx can result in the develoment of a neuroma.

• Usually the third interspace

Treatment objectives (unweight it)

1. pt must obtain relief from the pain and burning, especially in the third interspace of the MTP joint
2. Compression of the digital nerve as it passes between the heads of the third and fourth metatarsals mneeds to be reduced
3. shoe should be wide
4. reduce plantar flexion of MTP joints
5. Metatarsal bar to redistribute weight metatarsal rocker to immoblize the metatarsals

If bad enough, might have to surgically remove it

Question 6

What are the three rocker phases?

Answer 6

1. heel
2. ankle
3. toe

Question 7

what is an alternate name for rocker phase?

Answer 7

rocker moment

Question 8

What are two things that can change rocker phases

Answer 8

orthotics

shoes

Question 9

Explain the Heel rocker phase

Answer 9

It occurs from initial contact to loading response

happening at our heel (calcaneus)

• the calcaneus is the fulcrum as it strikes and the ankle immediatly begins plantarflexing
  
  • So the foot is pivoting around the tip of the calcaneus

Question 10

what happens to the heel rocker (1st rocker) if we make changes to the heal?

Answer 10

• make it take longer (make heel softer)
• make it take shorter (make heel harder)
• lock it (in orthotic or tight tight shoe)
• put foot in forced plantar flexion, no heel rocker moment (since heel doesn’t hit)

Question 11

Explain the ankle rocker phase

Answer 11

The foot is flat and stationary on the floor while the tibia rotates forward around the ankle (anterior translation)

Question 12

What are two things that can change the ankle rocker (2nd rocker)?

Answer 12

1. fused ankle won’t rock
2. If it is painful, the person will move throug the rocker quickly or not at all

Question 13

Explain the toe rocker (3rd rocker)

Answer 13

This occurs during terminal stance to toe off as the foot/leg rotates around the MTP joints.

Question 14

What are the three rockers for?

Answer 14

Rocker phases help reduce ground reaction forces and make the movement smoother

Question 15

Why do we care about the rockers?

Answer 15

Orthotics, shoe modifications, and/or pathologies can change one or more of them and affect normal gait.

For example:

• metatarsal bar shortens or gets rid of toe off (toe rocker)
• a rigid AFO definitely limits ankle rocker (but preserves some heel rocker)
• rigid AFO could limit all three rockers if it has long foot plate that extends past metatarsal head.

Question 16

what are two manufacture types of orthotics?

Answer 16

1. Prefab, OTC, or Off the Shelf
2. Custom

Question 17

Describe Prefab, OTC, Off the Shelf orthotics

Answer 17

Like Dr. Scholl’s

usually have some amount of adjustabilty

Question 18

Describe Custom orthotics, how they are typically made, using AFO as an example (5 steps)

Answer 18

1. Cast the person (for a foot only orthosis this may be pushing foot into a box of foam like what you can stick flowers in)
2. cut cast off (now you have a negative form)
3. fill the cast to create a positive form
4. Create AFO around positive (have another negative)
5. Make therapeutic changes to AFO
   
   • PT usually has a role in helping orthotist decide what to modify

Question 19

what are 5 materials often used to make orthotics?

Answer 19

1. Metal
2. Plastic
3. Leather (straps)
4. Velcro (straps)
5. Foam/padding

Question 20

What are two main types of plastic that are used in orthotics?

Answer 20

1. thermoset
   
   • once it is made it cannot be remolded
   • can cut and grind
   • Stronger than thermoplastic
     
     • Better for LE because it must withstand weight bearing force
2. thermoplastic
   
   • has ability to be reheated and molded
   • not as strong as thermoset
     
     • Better for UE because it doesn’t need to support weight bearing force
   • be careful not to leave in car in the summer!
     
     • A lot of splints are made with thermoplastic

Question 21

Three things about thermoset plastic

Answer 21

thermoset

1. once it is made it cannot be remolded
2. can cut and grind
3. Stronger than thermoplastic
   
   • Better for LE because it must withstand weight bearing force

Question 22

Three things about thermoplastic plastic

Answer 22

1. has ability to be reheated and molded
2. not as strong as thermoset
   
   • Better for UE because it doesn’t need to support weight bearing force
3. be careful not to leave in car in the summer!
   
   • A lot of splints are made with thermoplastic

Question 23

Metal vs Plastic: Contact

Explain the differences and pros and cons

Answer 23

Plastic

• full contact
  
  • forces distributed
  • doesn’t allow for swelling or wound healing
  • not breathable
  • hot

Metal

• partial contact
  
  • forces may be linear and through straps more than through the shell
  • more air flow
  • allows for wound healing

Question 24

Metal vs Plastic: weight, strength, pt preference

Explain the differences

Answer 24

Plastic

• lighter than metal
• Weaker than metal
• Pts typically prefer plastic

Metal

• heavier than plastic
• Stronger than plastic
• Pts typically prefer plastic

Question 25

Metal vs Plastic: cost

Explain the differences

Answer 25

Both metal and plastic can have variable costs, so that is not a clear way to distinguish the categories

Question 26

When choosing metal vs plastic for an orthosis, what is an additional consideration for pts with sensory issues

Answer 26

Consider sensory issues and how much pts (or family) check

• for non-checkers metal may be better

Question 27

UCBL Orthosis:

• Describe how it looks/what it is
• Purpose (what it does and how)
• Who/what is it for? (4-5)
• What movements does it allow? (2)

Answer 27

1. Custom orthotic Developed by University of California Biomechanics Laboratory (hence it’s name)
2. for subtalar joint instability
   
   • Controls
     
     • flexible calcaneal deformities (rearfoot valgus or varus)
     • transverse plane deformitys of the midtarsal joints (forefoot abduction or adduction)
   • “grabs” the calcaneus and supports the midfoot with hight medial and lateral trim lines
   • realigns the calcaneus
3. vast majority made for pediactrics
   
   1. something wrong with gait
   2. hypotonia (prevent collapsing)
   3. Development delay
   4. flexible pes planus
4. Allows
   
   1. normal toe off (because of short foot plate)
   2. ankle movement (because trim line is below ankle; so not helpful in swing phase)

More from pg 231 in book (if interested):

improves the angle of pull of the achilles tendon, providing a more stable foundation ofor the articular surfaces of the talus, navicular, and cuboid boines. Also used to improve functional alignment of children and adolecscents with flexible pes planus, a longitudinal arch deformity. The gillete modification, an external post positioned either on the medial or lateral border of the heel cup, can be used to apply additional rotatory moments to the calcaneus during weight bearing. The UCBL shoe insert may improve foot performance during stance for persons with hypotonicity. Not appropriate for persons with swing phase clearance issues (because the trim line is below the ankle)

Question 28

DAFO stands for what?

Answer 28

Dynamic ankle foot orthosis

Question 29

Alterate name for DAFO

Answer 29

SMO

(supramalleolar orthosis)

Question 30

T/F: The DAFO has moving parts (hence it’s name: dynamic ankle foot orthosis).

Answer 30

False

No moving parts

Name is strange

Question 31

DAFO Orthosis: (4)

Describe how it looks/what it is

Purpose (what it does and how) (2-3)

Who/what is it for? (4-5)

Answer 31

DAFO (dynamic Ankle foot orthosis), figure 9-10

1. Evolved from UCBL
2. Goes up around the malleoli (superior trim line just superior to ankle joint)
3. adds stability in mediolateral plane
   
   • locks the malleoli, but still has some ankle rocker (reduced though)
   • Limits MTP joints more with more anterior foot plate
4. Typically made for pediatric pts
   
   • Diplegic CP
   • helps with extensor hypertonicity
   • helps with foot clearance in swing phase

**often pts will not wear DAFO inside shoe (so grippy things are put on the outside of the orthosis so pt can walk on it without slipping)

Question 32

How often will we need to make new pediactric AFOs?

Answer 32

will be making them all the time because kids grow fast

Question 33

What is a solid ankle foot orthosis

Answer 33

if an AFO is a solid AFO it won’t have moving parts (with one exception)

**I think the exception is the Posterior Spring-Leaf AFO because it doesn’t have joints or true moving parts, but it is considered dynamic instead of fixed because it has a spring effect. (not sure though)

Question 34

Which rockers will a solid AFO affect and how?

Answer 34

Will affect most of the rockers

• definitely heel and ankle
  
  • Heel rocker doesn’t allow plantar flexion (disrupts loading response)
    
    • will go forward as we go flat
  • ankle rocker
    
    • doesn’t allow tibial translation
• toe rocker may be affected if foot plate goes far enough forward

Question 35

What AFO provides maximum ankle stability (apart from fusing the ankle)

Answer 35

Solid Ankle Foot Orthosis

Question 36

What is a trim line?

Answer 36

The edge of the plastic on a plastic orthosis

Question 37

What are the four main trim lines?

Answer 37

Superior

medial

lateral

foot plate

Question 38

Considerations for the proximal trim line in an AFO (2-4)

Answer 38

the proximal trim line is the top

• flared to prevent pinching
• must be correct distance from popliteal fossa
  
  • too short, it digs into gasroc
  • too long, digs into popliteal fossa ( won’t be enough room to sit)

Question 39

Considerations for the medial and lateral trim lines in an AFO (2)

Answer 39

medial and lateral trimlines

1. the further forward they come, the more mediolateral stability we get
2. don’t want them to come in too far or will pinch the tibialis anterior

Question 40

Considerations for the foot plate in an AFO

Answer 40

If the foot plate extendes beyond the metatarsal heads, it will prevent or impede MTP flexion and change the toe rocker

• this may or may not be desirable depending on our pt’s needs

Question 41

What are three angles that a solid AFO are commonly placed in?

Answer 41

1. Slight DF ( 5* or less)
2. Neutral
3. Slight PF (5* or less)

**Dr. brinman has examples of all of these

Question 42

When could we use a solid AFO set in neutral?

Why?

Answer 42

• basic foot drop (no spasticity, not knee issues, don’t read into it on test if he says they have foot drop)
  
  • Majority of trouble in swing phase (but also some in Initial contact to loading response)
  • Want to assist dorsiflexion during swing, so we put them in a neutral AFO (because there is no spasticity/knee weakness).
  • Hopefully we have not caused other problems (so neutral is best choice)

Question 43

When could we use a solid AFO set in DF?

Why?

example of a diagnosis that might require this?

Answer 43

Recurvatum

• We want to move ground reaction force slightly posterior to create a small flexion moment
  
  • What could we do to the ankle to cause this?
    
    • put in dorsiflexion so
    • we want slight dorsiflexion AFO to correct this slightly
    • at most 5* (Do not want to much DF or we may cause/exacerbate buckling)
• We want to prevent more recurvatum and damage to posterior capsule, etc.
• Typical of pt with stroke pt

Question 44

When could we use a solid AFO set in PF?

Why?

Answer 44

Buckling

• we are getting too much knee flexion
• landing in plantarflexion creates more of an extension moment
• Put them in slight plantarflexion AFO
  
  • they cannot get knee to move any more forward
• Makes knee stable, but disrupts gait cycle
• GRF stays anterior to knee
• Too much PF can cause/exacerbate recurvatum (so at most 5*)

Question 45

What two knee problems can we address with an AFO?

What is important to keep in mind with both of them?

Answer 45

1. Recurvatum
2. Buckling

For both of these, we are making just enough adjustment to move knee to neutral position (not past neutral into the position opposite of what we are trying to correct).

Question 46

Why make changes at ankle to fix knee? (3)

Answer 46

1. Whenever we can control a joint more distally, it is better to not go up higher because you will have less stuff on the leg.
2. Usually people with these knee problems also have foot involvement
3. If you had someone with isolated knee problem (uncommon), you might be able to apply something just to the knee (probably a KO, not a KAFO) but then you would be stuck in knee extension, etc.

Question 47

What is an alternative (and confusing) way of saying a brace is made in 5* of PF?

Answer 47

“AFO is made with a DF stop at 5* of PF”

(this often relates to Articulating/dynamic AFOs)