foot orthotics Flashcards
what is a foot orthotic
- device that is placed in a shoe to reduce or eliminate pathological stresses to the foot or other portions of the lower kinetic chain
- device used to support the foot, improve function, and improve alignment of the foot and/or lower extremity
functions of foot during gait
- provide base of support
- mobile adapter
- shock attenuation
- accommodation of transverse plane motion
- provide rigid support
talocrural joint axis
through malleoli
- lateral malleolus is inferior and posterior to medial malleolus
talocrural PF
adduction (inv)
talocrural DF
abduction (Ev)
subtalar joint open chain calcaneus pronation
everts, abducts, DFs
subtalar joint open chain calcaneus supination
inverts, adducts, PFs
closed chain pronation
- calcaneus everts
- talus adducts and PFs
- leg internally rotates
- knee flexes
closed chain supination
- calcaneus inverts
- talus abducts and DFs
- leg externally rotates
- knee extends
mid-tarsal joint longitudinal axis
pronation/supination
(eversion/inversion)
mid-tarsal joint oblique axis
PF/DF
tarsometatarsal joint purpose
keep MT heads on the ground
TMT joint supination twist
- 1-2nd MT DF secondary to GRF
- 4-5th MT PF secondary to flexor muscles
stance phase components
- initial contact
- loading response
- mid-stance
- terminal stance
- toe-off
swing phase components
- initial swing
- mid-swing
- terminal swing
goal #1 of foot
get both calcaneal condyles on the ground
at HS, STJ is in ______
supination
initial contact with lateral or medial condyle of calcaneus
lateral condyle
what has to occur to get medial condyle to ground
STJ pronation
goal #2 of foot
get metatarsal heads on ground
what has to occur to give forefoot mobility to adapt to surface
STJ pronates
goal #3 of foot
provide rigid lever for toe off
what happens to STJ during midstance
moves toward neutral, increasing the stability of the forefoot
what happens to STJ during terminal stance/toe off
STJ is supinated to provide rigid foot
max pronation or supination prior to toe off?
max supination
foot is in _____ prior to loading response
supination
STJ _____ occurs until 50% of the gait cycle
pronation
_____ initiated during mid-stance, by 60% of gait
re-supination
pronating or supinating foot during heel contact and foot flat?
pronating foot
pronating or supinating foot during neutral, heel lift, and toe off?
supinating foot
functional neutral standing position
- knees extended
- arms at sides
- feet 6 inches apart
- comfortable amount of toe-off
compensation definition
change in the structure, position, or function of one part to neutralize an abnormal force or a deviation in structure, position, or function of another part
foot orthotic functions
- distribute WB forces evenly on the plantar surfaces of the foot
- reduce excessive stresses to the proximal structures from pronation/supination
- reduce magnitude and rate of excessive pronation
- balance intrinsic foot deformities
orthotic indications
- LE/spine symptoms
- PT goals achieved or patient plateau
- course of therapy completed
what kind of orthotic for an intrinsic abnormality
controlling orthotic
what kind of orthotic for an extrinsic abnormality
accommodative orthotic
foot orthotic requirements
- conforms to contours of the foot
- rigid enough to control pronation, but flexible enough to allow normal motion
- capable of being adjusted with precision
- durable
- comfortble
- does no harm
- cost-effective
- lightweight
examples of extrinsic abnormalities
- coxa valga/vara
- tibial varum/valgum
- femoral anteversion/retroversion
- tibial torsion
- leg length discrepancies
- equinus deformity
what is the angle of inclination
angle between neck and shaft of femur
what is coxa valga
- increased angle of inclination
- increased compression at hip
coxa valga compensations
- genu varum (increased medial compression at knee; increased stress on popliteus, LCL, lateral hamstrings/gastroc/ITB)
- tibial varus > rapid pronation > posterior tib tendinitis > complain of medial leg symptoms
what is coxa vara
- decreased angle of inclination
- increased joint stability
- increased stress on femoral neck
coxa vara compensations
- genu valgum (lateral knee joint compression, medial knee gapping, VMO weakness, pes anserine, medial capsule)
- forced pronation (pain in arch of foot, medial malleolus, PT tendinitis at insertion)
what is tibial varum
- distal tibia deviated inward towards midline of body
- excessive inversion at heel strike
- calcaneus everts farther than normal
what is tibial valgus
- distal tibia deviated outward away from midline
- tend to contact ground with medial aspect of calcaneus
what is the angle of anteversion
angle between neck and shaft of femur in horizontal plane
what is femoral anteversion
- increased angle of anteversion
- shaft of femur faces medially
- rest of limb in alignment
- heel strike with pronated foot
- forefoot varus compensation
what is known as pigeon toed
femoral anteversion
what is femoral retroversion
- decreased angle of inclination
- feet point laterally
- contact more laterally > excessive pronation during loading response
what is tibial torsion
- external rotation
- contact with external rotation > quick pronation
what do you usually complain of with tibial torsion
PF symptoms
compensations for long leg
- rearfoot pronation
- knee flexion or hyperextension
- genu varum/valgum
- hip abduction
- pelvic tilt
compensations for short leg
- supination
- excessive PF
equinus deformity
- need 10 DF at end of mid-stance
- if DF inadequate, will pronate through STJ and mid-tarsal joint
- early heel rise if rigid
examples of intrinsic foot deformities
- subtalar varus
- forefoot varus/valgus
- forefoot valgus deformity
- PF 1st ray
normal subtalar joint neutral
- rearfoot: 0-3 deg varus
- forefoot: calcaneus perpendicular to MT line
what is subtalar varus
- inversion deformity of calaneus secondary to incomplete de-rotation during development
what is an osseous deformity
rotation within the calcaneus
- associated with subtalar varus???
what is forefoot varus
forefoot is in an inverted position relative to the calcaneal bisection, secondary to lack of de-rotation fo talus
what is forefoot valgus
forefoot in in an everted position relative to the calceaneal bisection
forefoot valgus deformity compensation
will occur through the rearfoot; rearfoot will be more supinated during mid-stance
orthotic components
shell and posts
soft shell goals and material
- pressure relief and shock attenuation
- soft foams
soft shell posts
extrinsic posts
soft shell indications
DM, hyposensitivity, pes cavus, supinatory foot
semi-rigid shell goal and material
- motion control and shock absorption
- cork, leather, low-temp plastics
semi-rigid shell posts
intrinsic or extrinsic
semi-rigid shell indications
motion control
rigid shell goal and materials
- CONTROL
- heat-moldable plastics; casting required
rigid shell posting
intrinsic
rigid shell indications
control of excessive pronation
posting functions
- control motion, bring ground to foot
- maintain abnormal joint relationships
- prevent compensation/reduce abnormal motion
- enhance muscle activity
intrinsic posting
- within shell of orthotic
- forefoot posting is almost always intrinsic
- decreased bulk to better fit in shoe
- difficult to adjust
- expensive
extrinsic posting
- most orthotics have extrinsic rearfoot posting
- stronger
- easier to adjust
- less arch pressure
- more bulk in shoe
varus post location
medial side of foot
valgus post location
lateral side of foot
0 deg post
- extrinsic post without angulation (LIFT)
- large FF varus, no RF abnormality
bar post
- runs straight, flat across
- usually extrinsic
- rigid PF 1st ray (bar post under rays 2-4)
rearfoot posting determination
- approximately 50% of varus
- max 6 deg
forefoot posting determination
- approximately 40%
- max 8 deg
age and weight posting determination
- more conservative with increasing age
- more aggressive with increasing weight
accommodative orthotic (soft shell)
- allows significant amount of flexibility
- supinatory foot type (improve shock absorption, distribute forces to foot, controls motion and lets foot come to ground more easily)
- congenital malformations
- ROM problems
- insensate feet
- diabetic/ rheumatoid feet
- illness, old age, unhealthy feet
- rigid PF 1st ray
biomechanical orthotic (rigid/semi-rigid)
- increased rigidity of shell
- durometer- indication of flexibility/rigidity (higher number = more rigid)
- pronatory foot problems
biomechanical orthotic requirements
- conform exactly to contours of foot
- sufficiently rigid to maintain contours with use
- control abnormal motion
- allow normal motion to occur in proper sequence
- stand up to stress and wear
- capable of being adjusted with precision
dual density
- usually semi-rigid shell
- provides control of excessive pronation
- softer, accommodating material on top
- allows shock attenuation
- easier for patients to break in
patient considerations for selection of orthotics
- patient condition
- pronatory vs supinatory
- intrinsic/extrinsic deformities
- patients footwear
- types of stress you are trying to reduce
- type of material
- customized vs over the counter
- cost
- fabrication time
orthotic break in period
- day 1: 1-2 hrs
- increases total wear time by 1-2 hours/day
- more rigidity = longer break in period
- tolerate 6-8 hrs/day prior to wearing for sports
- sports: begin 1/3 of time and increase by 1/3’s
orthotic longevity
- long term use: evaluate 1-4 yrs
- semi rigid: 1-2 yrs
- soft orthotics: 6 months to 1 year max
dress shoes and orthotic
- as heel height increases, function of orthotic decreases
- max heel height = 2 in
diabetes typical foot changes
- intrinsic foot weakness
- toe deformities (hammer/claw)
- prominent MT heads
- fat pad atrophy
diabetes shoe considerations
- wide toe box
- good plantar contact
- straight last
diabetes orthotic considerations
- decrease plantar pressures (total contact: 1st and 5th MT heads, talus, navicular)
best orthotic for diabetes
accommodative or dual-density
rheumatoid arthritis shoewear
- straight last
- good heel counter
- wide toe box
what kind of orthotic for RA with hallux rigidus
- rocker-bottom shoe or MT bar
primary cause of orthotic issues
shoe gear, worn post, orthotic fatigue, gouging of shoe insole by post, physiological changes in the patient
medial foot callus causes
- not fully controlling foot- pronating against orthotic
- excessively high post
lateral foot callus good or bad
good because it means you’re actually keeping foot in pronated position
orthotic postural complaints reasons
- not following break in schedule
- as a result you need to decrease wearing time
