Foot Orthoses: Assessment + Casting Flashcards
Define foot orthosis
- Device inserted into shoe
- support/accommodate/prevent foot abnormalities
- improve how the foot functions
Custom vs over the counter foot orthoses: 5 custom features
- produced via negative cast
- unique to patient’s needs
- covered by insurance
- available through skilled clinician
Custom vs over the counter foot orthoses: 5 OTC features
- mass produced
- not unique/customized to ptnt
- not typically covered by insurance
- available at pharmacies, sport stores, etc
- low cost option
Define Modified OTC foot orthoses
OTC device with additions/modifications to customize device
2D force plate tech may be used to guide MT pads; not a custom device
Mild symptoms, children, financial barriers
Define component OTC foot orthoses
OTC with prefabricated parts assembled to customize device
Not a custom device; different levels of support
Custom vs over the counter foot orthoses: 4 key differences
- OTC more cushioning than correction
- custom more control, precise adjustments
- heat mouldable products more effective done by clinician vs DIY
- custom typically longer lifespan (OTC 6 months - 1 yr)
Custom vs over the counter foot orthoses: 6 factors to consider when choosing
- urgency of ptnt situation
- short vs long term requirements
- significant biomechanical abnormalities
- ptnt activity level, occupation, environment
- cost barrier
Custom vs over the counter foot orthoses: 4 other pedorthic tools to consider
- footwear/modifications
- complimentary devices
- external referrals
- patient education
7 Common complimentary assistive devices
- compression therapy
- subtalar control AFO
- night splints
- below knee walkers
- ankle braces
- toe splints / spacers
- custom shoe fillers
complimentary device: compression therapy goal
Improve venous return and reduce swelling by supporting peripheral blood vessels
complimentary device: compression therapy supplements treatment for 3 condition categories
venous disease, varicose veins, chronic venous insufficiency, venous leg ulcers
edema, lymphedema
Clots, DVT prevention, postoperative treatment
complimentary device: subtalar control AFO goal
Manage function of anatomy distal to ankle by controlling subtalar ROM
Proximal length of scafo does not extend beyond junction of gastrocnemius and Achilles’ tendon; Richie braces, Arizona AFOs
complimentary device: subtalar control AFO used in treatment in what type of conditions
Conditions where foot requires more surface area to control forces
- severe posterior tibial tendon dysfunction
complimentary device: night splints 2 condition types
1st MTP joint conditions (hallux abductovalgus, bunions)
Ankle joint conditions (dorsiflexion - Achilles tendinitis, plantar fasciitis; dorsal / boot / strassberg sock)
complimentary device: night splints goals
- reduce joint angle of 1st MTP, alleviate pressure/pain
- keep ankle at ~90 degrees , maintain slight tension on Achilles’ tendon (reduce contracture), supplement treatment, improve recovery, prevent re-injury
complimentary device: below knee walker conditions
Fractures, wound healing
severe Achilles’ tendon injury, shin splints, ankle sprains, trauma to foot or lower leg
complimentary device: below knee walker goal
Divert plantar pressure to lower leg
Air bladders provide contact around leg (offload sole of foot)
complimentary device: ankle brace conditions
Multiple ankle conditions present
Ankle instability, posterior tibial tendon dysfunction, other ankle injuries
complimentary device: ankle brace goal
Support ankle
Variety of designs, support levels, complimentary to pedorthic treatment (add more)
complimentary device: toe splints and spacers goals
low barrier tools, improve alignment, reduce inter-toe friction
complimentary device: toe splints and spacers conditions
Treatment/prevention of mild toe deformities and/or skin conditions
complimentary device: custom shoe fillers (or custom to spacers) conditions
Spacers - Advanced toe deformities
Fillers - digital or trans MT amputation
complimentary device: custom shoe fillers (or custom to spacers) goals - 2 each
Spacers - improve alignment, reduce inter-toe friction (epoxy)
Fillers - reduce shift of foot within footwear, reduce shear, prevent further complications, low durometer material lined with low friction interface, improve comfort
3 main casting techniques
- non-weight bearing NWB
- semi-weight bearing SWB
- full weight bearing WB
Casting techniques: SWB
Performed seated or standing; ptnt and/or clinician will bear some weight through foot
Casting techniques: NWB
Performed seated, lying prone, or lying supine; no weight placed on structures
Casting techniques: WB
Performed standing with full weight bearing down
Main goals of casting (negative casts) x3
Goals vary with each ptnt.
- capture most desired position of ptnt foot
- accurately reflect ptnt foot anatomy
- establish solid, accurate foundation for fabrication of custom foot orthoses
6 common casting techniques
- plaster slipper or STS slipper cast
- foam box cast
- digital scanning
- contact digitizing
- wax
- direct mold
Casting techniques: Plaster slipper / STS slipper cast
- position
- 2 benefits
- orthotic type
- cast features
- NWB position (prone/supine) most common; occasionally SWB or WB
- captures rearfoot/forefoot relationship well
- easy for clinician to visualize, make fine tuning adjustments
- corrective: more aggressive functional orthotic
- negative cast has no accommodation for soft tissue expansion during casting, narrower positive cast requires dressing for soft tissue expansion and keeping foot in place when WB
Casting techniques: foam box cast
- position
- 2 benefits
- orthotic type
- cast feature
- typically SWB (seated or standing); occasionally WB
- particularly useful for ptnt with rigid deformity requiring accommodation
- ptnt unable to maintain a prone or supine position due to injury, medical condition, or pregnancy - accommodative
- cast permits quick intrinsic modifications
Most common style of casting
Foam box cast
Ease of use, rapid application versatility, readily available for purchase from orthopaedic suppliers
Casting techniques: digital scanning
- position
- benefits
- orthotic type
- cast features
- able to switch between NWB, SWB, and WB (no change in set up required)
- ptnt with mobility issues, complex plantar pressure considerations
- shows forefoot/rearfoot relationship or desired position, foot type
- reduction in shipping time/cost, carbon footprint, storage space/cost
- type
- cast is measurable
Casting techniques: contact digitizing
- benefits
- 3 limitations
- benefits similar to digital scanning (mobility, reduced shipping/costs)
- lower sensitivity / digital detail depending on number of pins per square inch
- greater chance of mechanical equipment failure
- not so good for severe deformities, wide feet, other anomalies
Distinguish the two digital casting methods
Digital scanning: 3D scanning tech renders virtual model of foot including skin texture
Contact digitizing: pins that raise/lower to measure contours of plantar surface
Casting techniques: wax sheets
- position
- benefit
- limitations
- NWB, SWB, or WB
- application similar to slipper method, but more positions
- must be applied correctly (skill involved)
Casting techniques: direct mold
- summary
- 3 limitations
- materials of an orthotic directly molded against ptnt foot
- high margin for error
- limited material options (low workable temperature)
- rejected by insurance companies
Casting techniques: 7 considerations when making choice
- positioning
- ptnt foot ROM, lower body ROM
- foot morphology/deformity
- how casting affects final device, type of device
- cost (time and $)
- urgency
- insurance requirements
A good foot orthoses can only be made from a good ________ and a good __________.
Cast & Lab process
Define essential work order
Official documentation of the design of the orthosis you intend to manufacture
AKA lab sheet, order form
Essential work order: core info x 4
Bare minimum - all materials for each step - specifications of thickness/size More information is better - positive cast modifications - special instructions
Essential work order: bad habits to avoid
- ambiguous terms (e.g. little bit, small amount, half of regular amount; use mm or fractions of an inch instead)
- terms or instructions such as ‘at the discretion of the technician’
Define cast (model)
3D physical or digital model capturing the anatomy and contours of the plantar aspect of the foot
Pedorthic treatment options for ptnt should always account for 4 factors
- age + wt of individual
- ADLs at home, work, sports, leisure
- condition presenting with
- structure and function of their foot
