Orthotics - Afos - General

Front 1

What are the 3 foot rockers? What portion of the GC does each correspond to?

Back 1

Heel - from IC to foot flat, including eccentric lowering/weight acceptance

Ankle - T/o MSt as tibia advances over fixed foot

Toe - TSt to PSw

Front 2

• What is the goal of all AFOs?
  
• What are the 5 fundamental gait prerequisites?
  

Back 2

• Assist in safe, energy-efficient gait
  

1. Stability in stance
2. Swing phase prepositioning
3. Clearance in swing
4. Adequate step length
5. Energy conservation

Front 3

• For whom may an AFO offer additional stability in stance phase?
  
• In which planes is control primarily enhanced? Which motions are controlled?

Back 3

• PW- pes equinas or calcaneal varus, specifically those s/p CVA
  
• Frontal (eversion/inversion), sagittal (PF/DF)

Front 4

• How does an AFO aid clearance in swing phase? For what types of deficits does this matter?
  
• How does an AFO aid swing phase positioning?
  

Back 4

• Aids DF, which is needed in PW-drop-foot, extensor synergy/, or poor timing
  
• Maintains ankle in neutral to prepare for weight acceptance

Front 5

• What are 2 ways AFOs facilitate adequate step length?
  

Back 5

1. Provides talocrural (DF/PF) stability in TSt/PSw, allowing a normal length step contralaterally
   
2. Preventing pathologically elongated limb length allows for normal ipsilateral step length

Front 6

• How do AFOs facilitate energy conservation in gait?
  
• For whom is this especially important? Why?

Back 6

• Guiding/controlling the ankle and knee diminishes the need for inefficient compensatory mechanisms
• PW-neuro pathology b/c it promotes independent community ambulation
  

Front 7

• How can the angle of an AFO be adjusted to compensate for quad weakness? Why does this work?
  

Back 7

• Setting AFO in PF biases knee extension

Front 8

• Where is skin breakdown most likely to occur for PW-MAFOs? Why?
  
• What are other benefits that MAFOs provide over standard AFOs?

Back 8

• Over straps b/c the molded plastic portion evenly distributes forces over the surface of the skin
  
• Lighter, easier fit within shoes, and easily modified for relief areas

Front 9

• What are general benefits to a static-type AFO?
  
• What, specifically, might make one a good fit for a patient?

Back 9

• To maintain stability at talorcrural, subtalar and forefoot joints
  
• To assist swing clearance, preposition foot for IC, and provide stability to knee/ankle throughout stance phase

Front 10

What 2 shoe modifications may compensate for loss of rockers

Back 10

• Increased heel cushioning can help compensate for heel rocker
  
• Rocker bottom sole can aid ankle/toe rockers
  

Front 11

• What are drawbacks to solid ankle AFOs?
  
• What are 3 features available for a solid ankle AFO? What are their benefits?

Back 11

• Rockers compromised, possibly requiring shoe modification to compensate

1. Trimlines anterior to malleoli (stiffer, greater resistance to PF/DF)
2. Tone inhibiting bar
3. Footplate length (longer prevents tone from allowing toes to curl around bottom; longer promotes knee extension by limiting toe rocker)

Front 12

• What is a floor reaction AFO? Who would use it?
• For whom is it non-indicated?

Back 12

• An AFO designed to promote knee extension in PW-quad weakness
  

• PW-genu recurvatum, PW-knee ligament instability, PW-knee flexion contractures >10º

Front 13

What 3 variables determines a floor reaction AFO's effectiveness? Howso?

Back 13

1. The degree of PF it is set in (prevents advancement of tibia over fixed foot, pushing GRF anterior earlier in stance)
2. Rigidity
3. Toe plate length (longer plate prevents toe rocker, maintaining anterior GRF)
   

Front 14

• For whom might a patella tendon bearing AFO be recommended?
  
• How does it work?

Back 14

• Anybody requiring reduced WB through the foot/ankle, such as PW-Charcot feet, PW-plantar ulcers, PW-foot fx
  
• AFO set to force 10º of knee flexion to load the AFO anteriorly, forcing the AFO to accept some of the bodyweight

Front 15

• In what plane does a supramalleolar orthotic (SMO) provide support? What motions does it control?
  
• What is it similar to?

Back 15

• It controls eversion/inversion in the frontal plane
  
• High top sneaker

Front 16

• What is the defining characteristic of the posterior leaf spring AFO? What does this result in?
  
• How does it affect each rocker?

Back 16

• Trim lines are posterior to the malleoli, resulting in a less stiff AFO the allows for a degree of rocker motion
  

1. Allows controlled lowering into PF at heel rocker
   
2. Allows limited DF as tibia advances over foot
3. Stiff enough to maintain 90º at PSw→IC

Front 17

How does weight acceptance guide a spiral AFO's function?

Back 17

• Weight is accepted at LR, released by MSt, possibly (?) decelerating heel rocker and aiding early ankle rocker
• Weight is accepted at TSt-PSw, allowing completion of ankle rocker and toe rocker, then recoils to 90º during swing
  
• Allows for rotation in transverse plane

Front 18

What determines the amount of control provided by spiral/hemispiral AFOs?

Back 18

• Thicker material provides increased support
• Hemispiral (180º turn) provides greater support than spiral (360º turn)
• Trimline height

Front 19

• What is the hallmark component of a conventional AFO?
• What is most common? Why?
• What else could be used to promote clearance in swing? How does this work?

Back 19

• Ankle articulation with control with stops and assists.
  
• A PF stop at neutral to aid swing phase clearance
• DF assist that coils up like a spring during TSt/PSw, then recoils to neutral for swing phase

Front 20

• For what type of person would a DF assist AFO or posterior leaf spring AFO be better than a solid AFO?
  
• When would these be worse?
  
• What are drawbacks to DF assist AFOs?

Back 20

• Anybody with fluctuating edema, as these are better able to accomodate; Also people with PNS disease or peroneal nerve disfunction.
• People with hypertonicity, or neuromotor equinovarus (each requires greater support)
• Heavier, no frontal plane support, ↓ surface contact

Front 21

• What are benefits of a hinged thermoplastic AFO?
  
• What requirement is necessary for this AFO to be useful?
• What feature is useful in the hinged model?

Back 21

• Allows for heel and ankle rockers and limits potential for knee hyperextension in stance
  
• 5º of active DF
• PF/DF stops

Front 22

• For whom is a hybrid metal/plastic AFO most useful?
• Why?
  
• How does AFO presence affect shoe size?

Back 22

• For people expecting rapid changes in function
• B/C it can provide great degrees of control, ranging from a solid molding with stops → spring-assisted → standard hinge
  
• Shoes used must be ¹/₂ to 1 size larger