AFO orthotics main Flashcards
(16 cards)
Characteristics of solid AFO
- Thick thermoplastic, low flexibility
- Anterior trim line may extend over both malleoli to maximize stabilizing forces
- Strong straps help control motions
What motions are affected with the use of a SAFO during gait?
- Foot is unable to go into PF
- Causes early knee flexion
- Cushioned heeled shoes help get the forefoot to the ground by compressing the heel
What happens at the knee with a SAFO during gait?
- In 5º DF, knee is prevented from gaining neutral knee extension, or knee is flexed at midstance
- In 5º PF, knee is prevented from flexion, or knee is hyperextended at midstance
What would an SAFO with long foot plate limit?
- Hallux extension
- Keeps GRF anterior to the knee, prolongs knee extension
- Helps increase stability of knee and limb during single knee stance time
- Rocker bottom shoes help mimic toe rocker
Characteristics of posterior leaf spring AFO
- Shallow heel cup provides less foot stability
- short foot plate does not give effective role in knee stability
- Anterior trim behind malleoli
- Material only has to be strong enough to hold foot in static DF against gravity during swing phase
What is the advantage of a posterior leaf spring AFO?
- Allows some PF to occur during loading response
- Allows DF during mid/terminal stance, which allows forward translation of the tibia over the ankle
What is the purpose of the ground reaction AFO?
- Uses GRF to help maintain knee stability during stance
- Limits DF, GRF remains ant. to knee, which increases stability
Why is the ground reaction AFO set into a few degrees of PF?
- To restrict ant. translation of tibia during ankle during the rocker force
- Increases stability of the knee
How does the carbon fiber DF-assist work?
- Flex in the material allows foot to go into PF at IC and LR
- Allows tibia to translate forward during ankle rocker phase
- Provides some energy stored during DF to assist with PF during preswing, will hold foot in DF
What is a BiCAAL ankle joint?
- Bichannel adjustable ankle lock
- Has springs to allow and assist motion and pegs to stop motion
Where would the peg be in a BiCAAL to limit DF?
Anterior channel
What is the purpose of a BiCAAL with DF stop?
- Weak Plantarflexors- controls amount of DF during the ankle rocker to limit the forward translation of the tibia.
- Weak Knee Extensors – helps to keep GRF anterior to the knee longer during terminal stance which promotes knee extension.
Where would the peg be in a BiCAAL to assist DF?
- Posterior channel
- Spring is compressed during preswing during PF, unloaded at initial swing
- Spring recoil assists with DF
Where would the peg be in a BiCAAL to limit PF?
Posterior channel
What is the purpose of a BiCAAL with PF stop?
- Foot drop
- Plantar spasticity - doesn’t allow increase activation of PF to cause PF motion
What is the purpose of a T strap?
- Control valgus and varus at the ankle
- Used on conventional metal upright braces
