Introduction to Orthotics Flashcards
What is an orthotist?
A person who specializes in the design, fabrication, fitting, and alignment adjustment of orthoses
What is an orthosis?
any device added to the body to stabilize or immobilize a body part, prevent deformity, protect against injury, or assist with function
What are the 4 basic goals of orthoses?
- Maintain or correct body segment alignment
- Assist or resist joint motion
- Provide axial loading via the orthosis, therefore providing relief of distal weight bearing forces
- Protect against physical insult
In regards to function what are the ideal characteristics of an ideal orthosis?
- Meets the individuals mobility needs and goals
- Maximizes stance phase stability
- Minimizes abnormal alignment
- Minimally compromises swing clearance
- Effectively pre-positions the limb for initial contact
- Is energy efficient with the individual’s preferred assistive device
In regards to comfort what are the ideal characteristics of an ideal orthosis?
- Can be worn for long periods without damaging skin or causing pain
- Can be easily donned and doffed
In regards to cosmesis what is the ideal characteristic of an ideal orthosis?
Meets the individual’s need to fit in with peers
What are the 6 types of LE orthoses?
- foot orthosis (FO)
- ankle foot orthosis (AFO)
- knee orthosis (KO)
- knee ankle foot orthosis (KAFO)
- hip knee ankle foot orthosis (HKAFO)
- hip orthosis (HO)
What are 2 categories of FOs?
- accommodative
- corrective
When and how is an accommodative foot orthosis used?
When the foot cannot attain neutral a FO may shim the gap to fix the positioning
How does a corrective foot orthosis work?
It helps the foot attain a neutral position by either unloading compromised tissue or providing total contact
What are 5 types of foot orthoses?
- heel wedges/posting
- SACH heel with rocker sole
- metatarsal bars
- University of California Biomechanics Laboratory (UCBL)
- Supra Maleolar Orthosis (SMO)/Dynamic Ankle Foot Orthosis (DAFO)
What are the most common prescribed external shoe modification?
The rocker sole and solid-ankle cushion-heel (SACH) heels
How do rocker soles assist with gait?
- mimic action of the forefoot joint
- aid in roll off
- simulate forefoot dorsiflexion
When can a SACH heel with a rocker sole be used?
whenever there is minimal or no motion at the forefoot joint or hindfoot joint, due to fusion, fracture, cast immobilization, orthosis design, pain, or arthritis
What is the purpose of the metatarsal bars?
The flat surface placed behind the metatarsal heads can help relieve pressure on the heads themselves
When should met bars be sued?
In patients with metatarsalgia who would benefit from a rapid transfer of weight from the shafts of the metatarsal heads to the distal end of the toes, with limited extension of the digits
Met bars are typically __ inch in vertical height
1/4
What is the major difference between metatarsal bars and rocker soles?
Met bars have a much flatter plantar surface, providing a broader area of contact with the ground
What does UCBL stand for?
University of California Biomechanics Laboratory orthosis
The UCBL is an orthotic intervention for what joint instability?
subtalar
The UCBL controls what 2 types of deformities?
- flexible calcaneal deformities (rearfoot valgus or varus)
- deformities of the midtarsal joints (forefoot abduction or adduction)
How does the UCBL control calcaneal and midtarsal deformities?
By grabbing the calcaneus and supporting the midfoot with high medial and lateral trim lines, which improves the angle of pull of the Achilles tendon, providing a more stable foundation for the articular surfaces of the talus, navicular, and cuboid bones.
The UCBL is also used to improve the functional alignment of children and adolescents with what deformity?
flexible pes planus (a longitudinal arch deformity)
Supra Maleolar Orthosis (SMO) are also known as what?
DAFO=Dynamic ankle foot orthosis
SMOs/DAFOs possess a low profile design that crosses the ankle, however they have ___ invasive trim lines than a standard AFO
less
What are the 2 functions of the DAFO?
- provides sagittal plane control of the ankle and foot during stance
- facilitates foot clearance during swing
Where do the DAFOs proximal trim lines fall? Distal?
just superior to the ankle joint
they encase more of the forefoot
The DAFO is extremely helpful in what patient population? Explain why and how…
In children with mild to moderate diplegic cerebral palsy, because it is designed to redistribute plantar pressures by reducing overall stimulation of reflexes that otherwise reinforce extensor hypertonicity
By providing a stable base during stance phase what 4 gait parameters does the DAFO improve in children with spastic diplegia?
- swing limb clearance
- stride length
- cadence
- self-selected walking speed
What is the biggest complain of DAFO use?
Sweaty feet due to the confinement of the foot within the plastic DAFO shell and shoe
What are the 5 categories of ankle foot orthoses?
- Metal bars
- Total Contact
- Floor reaction
- Unweighting
- Immobilizing
What is the SAFO aka?
Rigid AFO
What is the solid AFO typically made of and why?
A relatively thick thermoplastic to hold the ankle in foot in a biomechanical neutral position
The proximal border of the solid AFO is typically trimmed to fall 1.5 inches below what bony landmark?
head of the fibula
The footplate can be lengthened beyond the metatarsal heads distally into a toe plate if what is a concern?
hypertonicity
What is a disadvantage of having a longer footplate on the solid AFO?
it is more difficult to don shoes
How many control systems are incorporated into the SAFO design?
4
Describe the first control system in the SAFO for the control of plantarflexion during swing phase
There is a fulcrum force applied at the anterior ankle (Velcro, strapping, shoe laces) that is opposed by a distal counterforce upward under the metatarsal heads and a proximal counterforce at the posterior proximal surface of the AFO
Describe the second control system in the SAFO for the control of dorsiflexion during stance phase
There is an upward and inward compressive force at the posterior heel, opposed by a distal downward counterforce delivered by the shoe, and a proximal force applied by the anterior closure straps just below the knee
Because the ankle is locked in a SAFO there is a(n) ______ moment at the knee during stance
extensor
Because of its ability to create an extensor moment during stance a SAFO is useful in what types of patients?
Those with stroke, cerebral palsy, or other neuromotor dysfunction
Describe the third control system in the SAFO for the control of varus and inversion of the foot
A medially directed force is applied just above and below the lateral malleolus with laterally directed counterforces at the proximal medial tibia and the medial foot
Describe the fourth control system in the SAFO for the control of valgus and eversion of the foot
A laterally directed force is applied just above and below the medial malleolus with medially directed counterforces at the proximal medial tibia and the medial foot
When are bilateral metal uprights/bars used?
Only in specific situations such as a polio patient has been using them their entire life
Solid AFOs can take on different styles, what are a few of them?
- carbon fiber
- spiral
- posterior leaf spring (provides flexibility at the ankle)
- dynamic
What are a few advantages to using a total contact AFO?
- They provide a sleek, intimate fit with total contact to provide better control
- They are lightweight and easy to conceal
How should a total contact AFO be adjusted if there is midtarsal joint deformity with forefoot abduction or adduction?
trim lines are adjusted to capture the shafts of the first and fifth metatarsals
How should a total contact AFO be adjusted if there is too much subtalar valgus?
the height of the medial wall is increased, and a flange might be placed proximal to the medial malleolus
The overall goal of total contact AFOs is to limit what?
knee hyperextension
Floor reaction AFOs (FRO) use floor reaction forces through the tow aspect of the foot plat to prevent what?
forward tibial progression and subsequent knee collapse
In what type of patients is a floor reaction AFO typical used in?
Those with quadriceps weakness and decreased motor control of the knee, such as CP children with crouched gait and those post polio
Floor reaction forces do help to limit forward tibial progression and knee collapse it can be assumed these patients will still require the use of what type of AD?
Lofstrand crutches or roller walker
What type of patients are FROs not appropriate for?
- genu recurvatum
- ACL deficient knees
What transtibial socket type does the unweighting AFO utilize?
patellar tendon bearing
When are immobilizing AFOs commonly used?
Following a LE injury when ankle immobilization is desired such as distal tib-fib fracture, foot bone fractures, tendocalcaneous rupture, and possible in a diabetic foot that has developed Charcot’s foot
What are 2 specific immobilizing AFOs?
- Crow AFO
- CAM Walker
In what patient type is a Crow AFO used in?
Charcot ankle and foot and patients with chronic plantar ulcerations
True or False
AFOs can be articulated or nonarticulated
True
If motion assistance is the desired effect how can the double action ankle joint accomplish this?
a coil spring is placed in the channel and a screw is used to adjust compression until the desired level of assistance is achieved
If motion resistance is the desired effect how can the double action ankle joint accomplish this?
A solid steel pin is inserted instead of the spring to stop motion beyond a particular point in the ROM
How does functional neuromuscular electrical stimulation work?
A cuff containing small electrodes positioned laterally over the peroneal nerve allow for dorsiflexion activity
What are a couple of examples of wearable FES units?
- The Hanger WalkAide System
- Odstock Dropped Foot Stimulator
What are 3 reasons a knee orthosis may be used?
- genu varum
- genu valgum
- genu recurvatum
What are 3 types of KOs?
- Athletic KO
- Non-articulated KO
- Custom or off the shelf KO
Athletic knee orthoses are typically _____ and a major sensation that plays a role is proprioception
preventative
Why are athletic KOs sometimes considered controversial?
The short lever arms may not be sufficient to diminish realistic damaging forces
Describe a non-articulated KO
They are used for short term use and often make transfers and gait difficult
What is a name brand of a non-articulated KO that is used in patients with genu recurvatum?
Swedish knee cage
Off the shelf KOs provide _____ control of the knee and restrict what?
limited
gross motion
When are knee-ankle-foot orthoses considered?
Only when stability during stance cannot be effectively provided by one of the AFO options
KAFOs are prescribed when there is impairment of ankle control as well as what 2 other things?
- hyperextension or recurvatum that jeopardizes structural integrity of the knee joint
- abnormal or excessive varus or valgus angulation that occurs during weight bearing in stance phase
What are the 3 KAFO subtypes?
- Single/Double bar (upright) KAFO
- Total contact KAFO
- Ischial Weight Bearing (unweighting) KAFO
What are 5 advantages to using a single/double bar KAFOs?
- accommodates volume fluctuations
- cooler than total contact
- highest material strength
- has locking abilities
- can utilize various knee joints
What are 2 advantages of total contact KAFOs?
- more customizable
- distribute the load better
What is the brand name of the type of orthosis that is a lightweight variation of a traditional KAFO designed for persons with paraplegia after SCI?
Craig Scott Orthosis
How does the Craig Scott Orthosis in combination with posture provide stability?
Patients tend to stand with hip hyperextension, exaggerated lumbar lordosis, and a backward leaning trunk which when combined with the orthosis’ dorsiflexion-assist ankle joints and offset locking knee joints requires little or no muscular activity to provide enough stability for a two-point swing-through gait pattern when used with Lofstrand crutches
In what type of patients are ischial weight bearing or unweighting KAFOs used in?
paralytic limbs
What are the disadvantages of using hip-knee-ankle-foot orthoses?
They are very restrictive and laborious to swing-to or through in gait
What types of patients utilize hip-knee-ankle-foot orthoses?
- children with myelomenigocele
- SCI patients
What are 4 types of HKAFOs?
- Reciprocating Gait Orthoses (RGO/ARGO)
- postural
- total contact
- leather and metal upright
How does a reciprocating gait orthoses (RGO) work?
It uses the flexion power of one hip to extend the opposite hip
What types of special postural equipment is considered a HKAFO
- standing frames
- parapodiums
- swivel walkers
What is a disadvantage of RGOs?
Require high energy consumption so they never really have been functional for most SCI patients
In what types of patients are hip orthoses (HOs) used?
In children with Leg calve Perthes disease (AVN) or congenital hip dislocations
What does SWASH orthosis stand for?
Standing Walking And Sitting Hip Orthosis
What is the purpose of a SWASH orthosis?
Maintains femoral abduction in standing, walking and sitting
When is a hip abduction orthosis used?
In patients post-operatively to position the femoral head optimally within the acetabulum
Describe the components of bilateral metal upright AFOs
calf band and stirrups
What is the advantage of a carbon fiber AFO?
they are energy returning
Describe the cons of a spiral AFO
There is limited control in all planes (master or none)
What is the most commonly used AFO?
posterior leaf spring AFO
Describe the shape of the posterior leaf spring AFOs and the outcomes of the design
It has a skinny AP trim line which does not allow for good ML support
What is the advantage of a dynamic AFO?
contains an aggressive spring assist due to the fact that it tilts forward
Add to DOUBLE ACTION ANKLE
What does BiCAAL stand for?
Bichannel adjustable ankle lock
What is the most commonly used AFO? What is it used for?
posterior leaf spring (PLS) AFO
prevention of foot drop
Add to DOUBLE ACTION ANKLE
What does BiCAAL stand for?
Bichannel adjustable ankle lock
Describe the BiCAAL
An AFO that contains an ankle joint with the anterior and posterior channels that can be fit with pins to reduce motion or springs to assist motion
What is the Klenzak housing AFO?
A spring assist AFO that has double metal uprights with a single anterior channel for a spring assist to aid dorsiflexion
What determines the limits of ankle dorsiflexion in an AFO?
the anterior (DF) stop
What is the anterior stop typically set at in AFOs?
5 degrees
What does the 5 degrees of ankle dorsiflexion allow for?
knee flexion
What is the result if the anterior stop is set greater than 5 degrees?
The knee could buckle
What determines the limits of ankle plantarflexion in an AFO?
posterior (PF) stop
What is the posterior stop typically set at in AFOs?
5 degrees
What does the 5 degrees of ankle plantarflexion allow for? What are the benefits of this?
knee extension
It can be used to control an unstable knee that has a tendency to buckle
What is the result if the posterior stop is set greater than 5 degrees?
genu recurvatum or knee hyperextension
What do T straps do?
control varus and valgus at the ankle
A medial T strap buckles around the lateral upright and correct for _____
valgus
A lateral T strap buckles around the medial upright and correct for _____
varus
What are 2 types of KAFOs that can be used in SCI patients to walk with the knee locked?
- drop ring locks
- Pawl lock with bail release
Describe how the Pawl lock with bail release KAFO works
It hooks on to the back of a chair to push it up and unlock the knee
Add after HIP ORTHOSIS
What is a patellar bottom attachment used for?
To keep the foot off the floor in NWB patients
What is required when using a patellar bottom attachment?
a lift on the opposite LE
In what patient population is a patellar bottom attachment used in?
Legg-Calve Perthes disease
