Exam 4: Orthotics Part 2, Foot Deformities, AFOs Flashcards Preview

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Flashcards in Exam 4: Orthotics Part 2, Foot Deformities, AFOs Deck (47):

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


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



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

  • 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)



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

  • 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


Morton's Syndrome:

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

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


  • might change mechanics
  • might put too much pressure elsewhere


Morton's Neuroma

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

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


What are the three rocker phases?

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  1. heel
  2. ankle
  3. toe

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what is an alternate name for rocker phase?

rocker moment

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What are two things that can change rocker phases




Explain the Heel rocker phase

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

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

  • 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)

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Explain the ankle rocker phase


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

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

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


Explain the toe rocker (3rd rocker)

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


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What are the three rockers for?

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


Why do we care about the rockers?

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.


what are two manufacture types of orthotics?

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


Describe Prefab, OTC, Off the Shelf orthotics

Like Dr. Scholl's

usually have some amount of adjustabilty



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

  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


what are 5 materials often used to make orthotics?

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


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

  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


Three things about thermoset plastic


  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


Three things about thermoplastic plastic

  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


Metal vs Plastic: Contact

Explain the differences and pros and cons


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


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


Metal vs Plastic: weight, strength, pt preference

Explain the differences


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


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


Metal vs Plastic: cost

Explain the differences

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


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

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

  • for non-checkers metal may be better


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)



  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)

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DAFO stands for what?

Dynamic ankle foot orthosis


Alterate name for DAFO


(supramalleolar orthosis)


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


No moving parts

Name is strange


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)


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)

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How often will we need to make new pediactric AFOs?

will be making them all the time because kids grow fast


What is a solid ankle foot orthosis

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)

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Which rockers will a solid AFO affect and how?

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


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

Solid Ankle Foot Orthosis


What is a trim line?

The edge of the plastic on a plastic orthosis


What are the four main trim lines?




foot plate


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

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)


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

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


Considerations for the foot plate in an AFO

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


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

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

**Dr. brinman has examples of all of these


When could we use a solid AFO set in neutral?


  • 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)


When could we use a solid AFO set in DF?


example of a diagnosis that might require this?


  • 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


When could we use a solid AFO set in PF?




  • 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*)


What two knee problems can we address with an AFO?

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

  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).


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

  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.


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

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

(this often relates to Articulating/dynamic AFOs)