Foot Orthoses: Assessment + Casting

Question 1

Define foot orthosis

Answer 1

• Device inserted into shoe
• support/accommodate/prevent foot abnormalities
• improve how the foot functions

Question 2

Custom vs over the counter foot orthoses: 5 custom features

Answer 2

• produced via negative cast
• unique to patient’s needs
• covered by insurance
• available through skilled clinician

Question 3

Custom vs over the counter foot orthoses: 5 OTC features

Answer 3

• mass produced
• not unique/customized to ptnt
• not typically covered by insurance
• available at pharmacies, sport stores, etc
• low cost option

Question 4

Define Modified OTC foot orthoses

Answer 4

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

Question 5

Define component OTC foot orthoses

Answer 5

OTC with prefabricated parts assembled to customize device

Not a custom device; different levels of support

Question 6

Custom vs over the counter foot orthoses: 4 key differences

Answer 6

• 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)

Question 7

Custom vs over the counter foot orthoses: 6 factors to consider when choosing

Answer 7

• urgency of ptnt situation
• short vs long term requirements
• significant biomechanical abnormalities
• ptnt activity level, occupation, environment
• cost barrier

Question 8

Custom vs over the counter foot orthoses: 4 other pedorthic tools to consider

Answer 8

• footwear/modifications
• complimentary devices
• external referrals
• patient education

Question 9

7 Common complimentary assistive devices

Answer 9

• compression therapy
• subtalar control AFO
• night splints
• below knee walkers
• ankle braces
• toe splints / spacers
• custom shoe fillers

Question 10

complimentary device: compression therapy goal

Answer 10

Improve venous return and reduce swelling by supporting peripheral blood vessels

Question 11

complimentary device: compression therapy supplements treatment for 3 condition categories

Answer 11

venous disease, varicose veins, chronic venous insufficiency, venous leg ulcers
edema, lymphedema
Clots, DVT prevention, postoperative treatment

Question 12

complimentary device: subtalar control AFO goal

Answer 12

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

Question 13

complimentary device: subtalar control AFO used in treatment in what type of conditions

Answer 13

Conditions where foot requires more surface area to control forces
- severe posterior tibial tendon dysfunction

Question 14

complimentary device: night splints 2 condition types

Answer 14

1st MTP joint conditions (hallux abductovalgus, bunions)

Ankle joint conditions (dorsiflexion - Achilles tendinitis, plantar fasciitis; dorsal / boot / strassberg sock)

Question 15

complimentary device: night splints goals

Answer 15

• 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

Question 16

complimentary device: below knee walker conditions

Answer 16

Fractures, wound healing

severe Achilles’ tendon injury, shin splints, ankle sprains, trauma to foot or lower leg

Question 17

complimentary device: below knee walker goal

Answer 17

Divert plantar pressure to lower leg

Air bladders provide contact around leg (offload sole of foot)

Question 18

complimentary device: ankle brace conditions

Answer 18

Multiple ankle conditions present

Ankle instability, posterior tibial tendon dysfunction, other ankle injuries

Question 19

complimentary device: ankle brace goal

Answer 19

Support ankle

Variety of designs, support levels, complimentary to pedorthic treatment (add more)

Question 20

complimentary device: toe splints and spacers goals

Answer 20

low barrier tools, improve alignment, reduce inter-toe friction

Question 21

complimentary device: toe splints and spacers conditions

Answer 21

Treatment/prevention of mild toe deformities and/or skin conditions

Question 22

complimentary device: custom shoe fillers (or custom to spacers) conditions

Answer 22

Spacers - Advanced toe deformities

Fillers - digital or trans MT amputation

Question 23

complimentary device: custom shoe fillers (or custom to spacers) goals - 2 each

Answer 23

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

Question 24

3 main casting techniques

Answer 24

• non-weight bearing NWB
• semi-weight bearing SWB
• full weight bearing WB

Question 25

Casting techniques: SWB

Answer 25

Performed seated or standing; ptnt and/or clinician will bear some weight through foot

Question 26

Casting techniques: NWB

Answer 26

Performed seated, lying prone, or lying supine; no weight placed on structures

Question 27

Casting techniques: WB

Answer 27

Performed standing with full weight bearing down

Question 28

Main goals of casting (negative casts) x3

Answer 28

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

Question 29

6 common casting techniques

Answer 29

- plaster slipper or STS slipper cast - foam box cast - digital scanning - contact digitizing - wax - direct mold

Question 30

Casting techniques: Plaster slipper / STS slipper cast - position - 2 benefits - orthotic type - cast features

Answer 30

- 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

Question 31

Casting techniques: foam box cast - position - 2 benefits - orthotic type - cast feature

Answer 31

- 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

Question 32

Most common style of casting

Answer 32

Foam box cast Ease of use, rapid application versatility, readily available for purchase from orthopaedic suppliers

Question 33

Casting techniques: digital scanning - position - benefits - orthotic type - cast features

Answer 33

- 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

Question 34

Casting techniques: contact digitizing - benefits - 3 limitations

Answer 34

- 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

Question 35

Distinguish the two digital casting methods

Answer 35

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

Question 36

Casting techniques: wax sheets - position - benefit - limitations

Answer 36

- NWB, SWB, or WB - application similar to slipper method, but more positions - must be applied correctly (skill involved)

Question 37

Casting techniques: direct mold - summary - 3 limitations

Answer 37

- materials of an orthotic directly molded against ptnt foot - high margin for error - limited material options (low workable temperature) - rejected by insurance companies

Question 38

Casting techniques: 7 considerations when making choice

Answer 38

- positioning - ptnt foot ROM, lower body ROM - foot morphology/deformity - how casting affects final device, type of device - cost (time and $) - urgency - insurance requirements

Question 39

A good foot orthoses can only be made from a good ________ and a good __________.

Answer 39

Cast & Lab process

Question 40

Define essential work order

Answer 40

Official documentation of the design of the orthosis you intend to manufacture AKA lab sheet, order form

Question 41

Essential work order: core info x 4

Answer 41

``` Bare minimum - all materials for each step - specifications of thickness/size More information is better - positive cast modifications - special instructions ```

Question 42

Essential work order: bad habits to avoid

Answer 42

- 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’

Question 43

Define cast (model)

Answer 43

3D physical or digital model capturing the anatomy and contours of the plantar aspect of the foot

Question 44

Pedorthic treatment options for ptnt should always account for 4 factors

Answer 44

- age + wt of individual - ADLs at home, work, sports, leisure - condition presenting with - structure and function of their foot