O - Orthotics for NM Conditions Flashcards
what is an orthosis
externally applied device designed to modify structural and functional characteristics of NM/MSK systems
what in an orthotist
board certified clinician who designs, fabricates, delivers, and maintains orthotic devices (orthoses) for pts w NM/ MSK conditions
what is orthotics
specialty w/i field of medicine which describes design, fabrication, and application of orthoses
how are orthoses named
to describe the joints that are positioned w/i the device
we most commonly see AFOs and KAFOs
what are the 5 functional goals of an orthosis
- substitute for weak ms by providing external support
- limit motion to minimize pain
- dec risk of developing bony deformity or contracture
- offload forces during WBing to promote healing and preent injury
- position limb segments for optimal alignment
what joints do orthoses directly and indirectly impact
directly - joints crossed
indirectly - next proximal joint
what are the 3 orthotic design principles
same physics principles as w prosthetics
- pressure = force/ area
inc SA = more comfortable and effective - torque = force x distance
larger moment arms dec amt of force needed to control a joint - sum of forces = 0
what are common orthotic materials
metal and leather
thermoplastic
carbon fiber
fiberglass cast tape
foams
dacron strapping
thermoplastic and carbon fiber are the main materials you will see today
for casting - tend to not use plastic anymore, all fiberglass/synthetic materials
when were metal and leather materials primarily used in orthotics and why are they less commonly seen now
in 80s
- they are annoying to make
- attached physically to one pair of shoes
they are effective
what is the purpose of the flexible inner boot
control FF
what is a casting block and why is this important
set the foot on a casting block when casting
* matches heel height in shoe
* want calcaneus in neutral
what pt cases is scanning more commonly utilized as a shape acquisition technique and why
spinal orthotics
larger surface
can still use scanning on LE
casting is becoming less common as other shape acquisition techniques are inc in popularity
what is often the purpose of modifying a cast/orthosis? in AFOs what is a common location for modifications?
accentuate WBing areas and areas w bony prominences
malleoli
in the interdisciplinary team what 3 members have a relationship that is most crucial for orthosis success
PT
OT
orthotist
in collaboration w patient
UMN pathologies
what is an UMN?
what are 3 characteristics of UMN damage?
what are examples of UMN conditions?
motor neuron which travels from brain to spinal cord
- initial weakness
- spasticity, hypertonicity, hyperreflexia
- dec motor control (speed, accuracy, coordination, fluidity)
ex: CVA, TBI, MS
what characteristic of UMN damage is often what triggers the referral to brace clinic
dec motor control (speed, accuracy, coordination, fluidity)
what is likely the biggest pt population utilizing AFOs
stroke pts
8 clinical presentation characteristics in CVA pts
- changes in resting tone (initial hypotonus)
- spasticity
- weakness / paralysis - stiff knee gait
- postural issues
- loss of proprioception
- sensory deficit
- neglect of affected side
- cog, emotional, intellectual impairment
how will the clinical presentation of weakness or paralysis in CVA pts translate into abnormal gait
stiff knee gait
3 clinical presentation characteristics in TBI pts
- difficulty w speech or communication
- hypertonicity
- balance challenges
what is a TBI
non-degenerative, external trauma to the brain
what is the prognosis w a TBI
may or may not recover
4 clinical presentation characteristics in MS pts
- usually BL
- poor balance
- lack of coordination
- sensory challenges (temp sensitive)
what characteristic of MS is often what triggers the referral to brace clinic
poor balance and lack of coordination
what ambulation compensations are seen in MS
wide BOS
small step lengths
how should an orthotic intervention be handled in MS
should be “delicate”
* more effective early on in dz
* MS is progressive
4 clinical presentation characteristics in SCI pts
- mixed UMN and LMN injury
- may be incomplete or complete
- can have high or low ms tone
- may have sensory issues
RGO
what is it
what are cons
when would you use it today
- reciprocal gait orthosis
- cumbersome, hard to put on
- might use to get pt upright for few hours a day
SCI
T12 intact: what orthotic?
RGO/HKAFO
SCI
L1 intact: what orthotic?
KAFO
SCI
L3 intact: what orthotic?
KAFO/AFO
SCI
L4 intact: what orthotic?
AFO
LMN pathologies
what is an LMN?
what are 3 characteristics of LMN damage?
what are examples of LMN conditions?
motor neuron which travels from SC to ms
- weakness
- hypotonicity, hyporeflexia, flaccidity
- fasciculations (involluntary ms twitches)
ex: GBS, polio, PPS, CMT
what is muscle tone and how does this impact compliance to orthoses
ms tone = interplay b/w compliance and stiffness of ms, as influenced by CNS
low tone = low stiffness, high compliance
optimal tone = mod stiff, mod compl
high tone = high stiff, low compliance
higher tone can make it difficult for orthotist to obtain a decent cast, harder for pt to be compliant and keep control
what is hypertonicity
ms that are too stiff (aka high tone)
what is spasticity
velocity-dependent hypertonicity (stiffness that occurs w rapid passive elongation of a ms)
what is rigidity
bidirectional, co-contracting hypertonicity and resistance to passive mvmt of both agonistic and antagonist ms groups
what is hypotonicity
dec ms stiffness (aka low tone)
what is flaccidity
ms cannot be activated bc of interruption of transmission or connection b/w LMN and ms (aka no tone)
what is athetosis
when underlying ms tone fluctuates unpredictably
why would an orthotist break down the functional tasks of gait
break down gait to see where interventions will be most effective and needed
what are 5 factors that influence gait and which 2 can we have the biggest impact with
1. stance phase stability
2. clearance in swing
3. swing phase pre-positioning
4. adequate step length
5. energy conservation
what type of orthosis is considering the rockers important for
AFOs
what are the 3 rockers in gait
heel
ankle
toe
heel rocker
what is its function (2)
what 2 ms are activated and why
- controlled lowering of foot
- body weight acceptance
eccentric control of quads and ant tib
* prevents foot slap and protects knee
ankle rocker
what is its function
what ms is activated and why
tibia progresses over WBing foot during mid to terminal stance
eccentric control of PFs
* limits forward mvmt of shank
toe rocker
what is its function (2)
- FF becomes rigid lever in pre-swing
- heel rise off ground for push off in late stance thru DF of MTP joints
how would disruption of the forward progress facilitated by the rockers negatively impact gait (3)
step length
cadence
SLS
what roll should orthosis play with rockers in gait
provides external support to ensure forward progression and mobility
* use least amt of external support possible
prefab orthoses
5 advantages vs 4 disadvantages
advantages:
* available in variety sizes/ materials
* can use as eval tool on where to go
* less expensive
* good short-term solution
* quicker off the shelf (not go thru whole casting process)
disadvantages:
* less control of pt’s limb
* less durable -> meant for temporary use
* not adjustable/customized -> not appropriate for complex presentations
* can cause skin breakdown d/t “generic” fit
prefab orthotics
5 indications vs 4 contraindications
indications:
* foot drop (CVA, TBI, SCI, MS)
* mild ankle instability
* mild spasticity
* adequate ROM
* mild/mod knee flex instability
contraindications:
* neuropathy/ulcers (concern for skin breakdown)
* severe spasticity
* contracture that can’t be accommodated
* excessive knee flex / hyperext in midstance
are prefab or custom molded orthoses more commonly used
custom molded
custom molded
4 advantages vs 5 disadvantages
advantages:
* optimal control of limb
* intimate/custom fit
* more durable
* more of brace present
disadvantages:
* more time consuming to fabricate
* more expensive
* difficult to fit into shoes
* may be hot to wear
* ongoing process of getting adjustments
custom molded
indications vs contraindications
indications:
* impaired sensation
* hypertonicity
* risk of progressive deformity
contraindications:
* only short-term devices use is needed
* large fluctuations in volume (will need to use conventional design)
if large fluctuations in limb volume w swelling, prefab may be better option bc less material to it
footwear
what qualities do you look for?
what type of footwear work best?
w extra depth, removable insoles, detached tongues
shoe closure - help stabilize calcenus w/i orthosis
may need to inc shoe size to accommodate orthosis
oxford style or athletic shoes are best
* billy shoes, new balance, zappos, plae, stride rite
struggle of appropriate footwear vs cute shoes
what is a custom foot orthosis
custom insert that works to improve foot mechanics during walking
what is a UCBL
basically a heel cup - keeps calcaneus in neutral
custom insert that addresses subtalar joint instability
* controls flexible calcaneal deformities
* controls transverse plane
* controls midtarsal deformities
UCBL = university of cali berkley
what is the primary goal of an AFO
provide just enough external support for stability in stance w minimal compromise of forward progression
AFO
what are 2 indications
- need direct control of STJ and ankle joint
- need indirect control of knee joint
AFO
static vs dynamic
static (solid ankle) - ankle locked in position
dynamic (articulated) - articulation via mechanical joint or allows flex/ext where and when we need it
what is the axis of the ankle joint
oblique running ant-med to post-lat
what ankle motions accompany DF and PF
DF:
* talar pron
* talar ABD
* RF valgus
PF:
* talar sup
* talar ADD
* RR varus
what is the most supportive/aggressive AFO
static
static AFOs
why are trimlines and shoe modifications important considerations
inc rigidity greatly compromises transitions thru all 3 rockers
* consider trimlines/shoes to maintain forward progression of shank
restricts ankle motion in all 3 planes
might consider shoes with a rocker bottom to help w forward progression
what is an indirect role of ground reaction AFOs
indirectly controls knee ext
static AFO
how are ground reaction AFOs fabricated
ankle in slight PF
static AFOs
how does PTB-AFOs offload weight from the plantar surface of the foot
PTB = patellar tendon bearing
anterior shell modified to accept weight via:
* total contact
* pressure tolerance areas - medial tib and patellar tendon
vertical uprights transfer forces
essentially just loading the patellar tendon
static AFOs
why is it hard to get a good result in pts appropriate for the PTB-AFO
pt often already has a lot of damage to foot by the time they are referred –> probably would have done better w an earlier referral
what are 3 things you need to be considered appropriate for a PTB-AFO
- normal anatomic structure of knee
- adequate MMT/motor control of quads
- sufficient skin integrity
static AFOs
what is the degree of control influenced by
direction of forces/counterforces, trimlines, and intrinsic modifications w/i the device
static AFOs
what are the 4 distinct control systems
- PF (swing)
- DF (stance)
- eversion / valgus
- inversion / varus
want varus/valgus angles to be in neutral and control inv/eve
what are 3 types of static AFOs
solid AFO
ground reaction AFO
weight relieving AFO (PTB-AFO)
what are 4 types of dynamic AFOs
articulated AFO
posterior leaf AFO
supramalleolar orthosis
conventional double upright AFO
dynamic AFO
in what patient would you consider a conventional double upright AFO
pt w fluctuating edema bc lot less contact (only at calf/shoe)
what are dynamic AFOs
ie what is their function
allow sagittal plane motion at ankle
* usually allow DF during stance and prevent PF during swing
dynamic AFOs
who are supramalleolar orthoses commonly used in
kids with mild to mod diplegic CP
dynamic AFOs
what are 5 functional improvements seen from a supramalleolar orthosis
- improve upright posture
- improve swing limb clearance
- stride length
- cadence
- self selected walking speed (SSWS)
dynamic AFOs
what are the 2 main functions of a posterior leaf spring AFO
preloads spring during stance, springs. back when you lift heel into swing phase
- support wt of foot during swing phase
- assist w controlled PF during loading response
dynamic AFOs
what is an advantage and disadvantage of posterior leaf spring AFOs
advantage - inc flexibility allows functional advantage (esp on slopes, ramps)
disadvantage - not effective at controlling calcaneus (not enough material at trimlines)
dynamic AFOs
what are 4 functional benefits of an articulated AFO
dec energy expenditure
improve stride length
cadence
SSWS
dynamic AFOs
what is an articulated aFO
allows sagittal plane motion via mechanical ankle joint
* allows wide ROM
* can modify amt of motion allowed per pt
similar control system to SAFO except for inc sagittal plane motion
what are 4 modifications to an AFO that can dec effects of hypertonicity/spasticity
- MT bar/dome to change MT head loading
- mechanism to encourage toe ext
- additional loading on either side of distal point of achilles tendon attachment
- ankle held in neutral ST and DF position
what is the primary goal of KAFOs
provide just enough external support for stability in stance and clearance in swing w minimla compromise of forward progression
how do pts feel ab KAFOs
they hate them - acceptance rate is low
what are 2 indications for KAFOs
- need direct control of ankle and knee joints
- need indirect control of hip joint
when should a KAFO be considered (4)
- excessive recurvatum at knee
- excessive varus or valgus at knee
- grade 3 or below MMT of quads
- impaired proprioception at knee
since pts hate KAFOs, what could you try first if they have weak quads
- GRF AFO to see if help w knee ext
- could cast foot into extra DF to push knee into little more flex and prevent hyper ext
what are considerations of a solid vs articulating ankle joint in a KAFO
consider how orthotic control of ankle and GRF will impact knee function and forward progression
* if allow ankle motion, can help w overall gait pattern
what knee joint would you use to
stabilize flail knee w SOME ability to generate knee ext moment (MMT 2 to 3+)
offset unlocked
what 2 knee joints would you use to
stabilize flail knee with NO ability to generate knee ext moment (MMT 0 to 2)
single axis locked
offset locked
what knee joint would you use to
reduce knee flexion contracture
variable positioning
what 2 knee joints would you use to
control genu valgum/varum
single axis unlocked
offset unlocked
what is the function of a stance control knee joint
allows locks on heel strike in stance but triggers into flex in swing
what is a ring/drop lock and what is a con of this
automatically locks knee joint into full ext
con: need hand dexterity to unlock the sides in sync to sit
what is a lever lock and what is a pro of this
locking knee joint with a release mechanism
pro: can unlock and lock both joints simultaneously when go to sit
this is the better version of a ring/drop lock
what is a bail lock, what is pro/con
metal rod connecting med and lat lever locks for simultaneously unlock
pro: can back up to wc to unlock
con: could accidentally bump, can’t wear under clothes
what is a cable/trigger lock and what is a pro of this
same as function as lever lock - med and lat lock connected to cable to unlock simultaneously
* less likely to accidentally unlock
variable positioning locks
what are they
what is an indication
allows locking of knee at various deg of knee flex (via dial lock like ACL brace), fully locked during stance/swing and unlock to sit
indicated in knee flexion contractures
provides stability despite GRF being posterior to anatomical knee center
what patient populations are stance control locks indicated in
initially developed for PPS
CVA, brain tumor, TBI, incomplete SCI, spinal degen dz, MS, peripheral nerve injury
stance control lock during gait
locked when weighted
* locked in ext from IC through terminal stance
unlocked when unweighted
* goes into free swing from preswing thru swing phase
what are 2 things needed for a stance control lock to be indicated
- must have at least 3/5 MMT at hip ext and hip flex
- must have full knee ext ROM
what are 3 advantages to a stance control lock
- improved SSWS, cadence, and stride length
- improved gait symmetry
- reduced compensatory patterns
how does an RGO work
who was it designed for
what is a con
- get reciprocal motion as pt shifts weight and ext trunk –> ext leg
- incomplete SCI
- not overall effective gait so long term acceptance is low
what are 2 indications of HKAFOs/RGOs
- need direct control of ankle, knee, and hip joints
- need indirect control of trunk
what are 3 examples of some pathologies that a HKAFO/RGO would be indicated for
- myelomeningocele
- high level SCI
- progressive neuro disorders
what are 4 disadvantages to HKAFO/RGO
- heavy
- high energy cost
- difficult to fabricate
- challenge to don/doff
what are 3 functions to a HKAFO/RGO
- limited amb
- standing for tasks
- standing contributes to bone health, skin integ, digestive/urinary/bowel health, respiratory capacity, CV fitness, and psych health
