Plastic AFO Flashcards
To determine the proper AP heel placement on a footboard
Place the shoe to be worn along side of the foot board and mark on the footboard where the heel will be situated in the shoe
Which of the following body landmarks should be marked when taking an AFO impression?
Both malleoli The base of the fifth The head of the fifth The head of the first Neck of fibula and Navicular
What linear measurements are required to fabricate a plastic AFO?
The ML diameter at the Apices of the malleoli and the height of the fibular neck.
In general, the desired position of the subtalar joint in a plastic AFO is?
Neutral
Stockinette is used when taking an impression for an AFO?
To protect the patient and provide a separator for pouring plaster
The goal of a proper plastic impression on the plantar aspect of the foot is?
To provide a smooth, uniform surface
To prevent inadvertent deformation of the plantar aspect of the impression, it is recommended that?
A separator be used such as the plaster bandage wrapper
A smooth, conforming impression can be obtained by?
Using a layer of elastic plaster bandage first
When using an oscillating cast saw for removal of an impression the proper technique involves
Alternating an advancing up and down motions
Cast modifications for plastic AFO includes removal of material from the heel medically and laterally in order to?
Provide a good gasp of the calcaneus
The plantar surface of the cast is flattened at the heel and forefoot to?
Ensure joint neutrality and provide a stable base of support
Unless otherwise indicated, the cast build-up for the malleoli
Is 3/16 inch (5mm) laterally and 1/4 inch (6mm) medially
Which of the following bony prominences should be built up on a cast a polypropylene AFO?
Base of the 5th
Navicular
Malleoli
And tendon calcaneus
The distal trim line on the plantar surface of a plastic AFO is?
Toe crease, distal tip of the toes, or proximal to the met heads
The minimal clearance between the proximal edge of a plastic and the neck of the fibula is
20mm
To ensure uniform vacuum forming during fabrication of the plastic AFO it Is sometimes helpful to
Carve A groove in the cast and use thin nylon stocking
The appropriate temperature for vacuum for polypropylene is?
20 gdghdnsn
To minimize expansion and contraction warping of a polypropylene AFO, it should be left on the cast and not removed for?
16 hours
Progressive posterior trimming of a plastic AFO about the malleoli will
Increase flexibility in all planes
What is the main reason scratches and sharp corners are avoided when finishing a plastic AFO
To avoid creating stress risers which could cause premature failure
Symmetrical trim lines about the ankle are important in
Preventing twisting of the AFO about the long axis in stance
The anterior closure of a plastic AFO is frequently comprised of a strap with Velcro wrapped back onto itself through a chafe in order to?
Reduce the shear force on the closure by 50%
if two rivets are used to fasten one end of a strap on an AFO, before attaching the second rivet it is necessary to?
Establish the correct angle of the strap
When a plastic AFO is on the patient along with the shoe, what portions of the patients leg and foot receive forces as the patient attempts to plantar-flex his ankle joint?
Posterior -proximal leg and dista, plantar aspect
When a plastic AFO is on the patient along with the shoe what portions of the patients leg and foot receive force as the patient attempts to dorsiflex his ankle joint?
Anterior proximal and anterior distal
What areas of the patients foot receives pressure when a patient wearing a plastic AFO tries to invert his subtalar axis?
Medial foot, medial proximal calf, and area proximal to lateral malleolus
What areas of the patients foot receives pressure when a patient wearing a plastic AFO tries to evert his subtalar axis?
Lateral foot, lateral proximal calf, and areas proximal to medial malleolus
What component can be added to a plastic AFO to increase resistance to plantarflexion?
A dorsal strap near the malleoli
The best technique for increasing the rigidity of a plastic AFO without significantly increasing weight or bulk is to?
Incorporate crescent shaped carbon composite inserts in the area of the malleoli
Why is a plastic AFOs proximal trim line adjusted so that it is 3/4” (20mm) from the neck of the fibula?
To avoid pressure on the Peroneal nerve and to obtain maximum bio mechanical leverage
What insert modification can be employed to reduce toe clawing?
A metatarsal pad
If a plastic AFO is made sufficiently flexible to allow controlled plantar flexion what is it good idea to trim the proximal edge more than normal amount?
To allow for proximal motion of the calf shell during plantar flexion adjacent to the Peroneal nerve.
What is likely consequences of placing a lower than anticipated heel height on a rigid polypropylene AFO?
Knee hyperextension
What is a likely consequence of placing a higher than anticipated heel height on a rigid polypropylene AFO?
Knee flexion
Why might it be a good idea to fabricate a plastic AFO in plantar flexion?
To reduce knee flexion thrust at loading
Why might it be a good idea to fabricate a plastic AFO in dorsiflexion?
To reduce knee extension thrust at loading
Two acceptable techniques for relieving pressure at a specific location on plastic AFO are?
Relieve the area by heating and creating a pocket or increase pressure surrounding the area
A foot board is used when taking an impression for a plastic AFO in order?
To duplicate the heel to sole height difference in the shoe to be worn
