Orthotics Flashcards
What is the purpose of orthotics?
- control abn. compensatory movements (by bringing the foot to the floor)
- to create a biomechanical balanced kinetic chain by controlling/reducing pathologic motion in the LE by keeping the foot in a subtalar neutral position
Why does the subtalar joint become rigid during toe off?
to propel an individual forward during gait
What is a foot orthotic and its purpose?
- they are wedges for supination/pronation
- to maintain biomechanical alignment
- used to correct knee varus/valgus
- prevents/helps with pain, pressure distribution, and skin protection
Describe what the center of pressure of the foot should look like for good biomechanics?
The center of pressure should start at the calcaneus during loading response, moving laterally towards the midfoot in midstance, and end medially towards the big toe during push off.
Which is most frequently encountered as an issue overpronation or excessive supination?
Overpronation; it leads to knee valgus and increased medial force through the patella
Why is subtalar joint flexibility and stability important during gait?
The subtalar joint requires flexibility for uneven surfaces, gait, and balance.
What occurs in the subtalar joint during initial contact?
- the subtalar joint is in neutral
- assists in shock absorption
- pronation of the subtalar; rotation of the tibia to absorb
- flexible
What occurs in the subtalar joint during midstance?
- the foot moves into full pronation during loading response
What occurs in the subtalar joint during terminal stance?
- the foot moves into supination and becomes rigid
How should the LE ideally look like when performing a standing assessment of alignment?
- the ASIS, patella, and midpoint between the malleoli should be in alignment
What are the repercussion of overpronation in a closed chain position?
- anterior pelvic tilt
- internal rotation (femur, fibula, tibia)
- valgus knee
In which directions does the talus and calcaneus shift when overpronation occurs?
- the talus shift medially (add. and plantarflexion) while the calcaneus shifts laterally (everts)
What movement occurs at the pelvis during over pronation?
- the pelvis experiences an anterior tilt
What are the repercussions of supination in a closed chain?
- posterior pelvic tilt
- external rotation (femur, tibia, and fibula)
- knee varus
What occurs to the talus and calcaneus during supination?
- the talus shift laterally (abd. and dorsiflex) while the calcaneus shift medially (inverts)
How would you measure for knee varum?
- you would measure between the knees
How would you measure for knee valgus?
- measure between the ankles/malleoli
What is KAM and its significance?
- KAM: knee adduction movement
- KAM increases GRF
- during walking KAM places the knee into varus and causes an increase in medial compressive forces (60-70% of force passes in medially)
What is the purpose of foot orthotics?
- supportive apparel that provides soft tissue protection, bone/joint stability (static & dynamic) , and controls the body segment
What do inside shoe orthotics (inserts) provide?
- modify heel, midfoot, or forefoot
- padding for pain
- heel lift for pain
- wedges for excessive sup/pron
What are UCBL’s and their purpose?
- UBL’s: University of California Berkely lab
- characteristics: high trim lines
- orthotics for arthritis, hypotonia
- hold the calcaneus in neutral
- mainly used for over pronation
How do you perform a navicular drop test?
- record subtalar neutral on a piece of paper (neutral found when navicular and cuboid bone are in parallel)
- record subtalar position during weightbearing
- positive test found at 10 mm difference
What gait deviations do you look for in the swing phase?
- drop foot
- consider AFO or leaf spring
What gait deviations do you look for in stance phase?
- ankle instability (solid AFO or hinged AFO)
- ankle plantarflexion (solid AFO w/support strap)
- knee hyperextension (inserts that keep the joint at neutral)
AFO’s are widely prescribed for..?
- weakness, stroke, cerebral palsy, head injury, peripheral neuropathy, alignment, SCI, progressive disease
When is an orthosis most comfortable and effective?
- Pressure= F/A
- Able to control direction of primary force and direction of counterforces
When is a leaf spring AFO most useful?
- when a pt is experiencing foot drop
- most effective in swing phase (enhances swing limb clearance and assists with controlled heel contact)
What are some reasons why a patient might be experiencing a foot drop?
- peripheral neuropathy (fracture, diabetes, bed rest, etc)
- MS
- Stroke or CVA
- myositis
What are the characteristics of a step smart AFO and what is it used for?
- Has a posterior shell
- Used for foot drop
What are the characteristics of a F3 carbon fiber AFO and what is it used for?
- it is light weight; durable, w/ anterior shell
- dorsiflexion assistance, enhances plantarflexion power
What are the characteristics of a solid AFO (SAFO) and what is it used for?
- to resist PF during swing
- has 2 straps (one at the calf and one at the ankle)
- has larger trim lines for more tibia control
- wider control of foot plat to prevent excessive inversion and eversion
What are the disadvantages of a SAFO?
- interferes with all 3 ankle rockers
- lose tibial advancement, 1st rocker
- no knee flexion or toe off leading to decrease stride length
What is a static AFO and its characteristics?
- rigid
- positioned for 0 degrees of dorsiflexion w/ a balanced forefoot
