Orthoses Thermoplastics & Terminology Flashcards
what are different types of orthosis materials?
- Low temperature thermoplastics (LTT)
- High Temperature thermoplastics
- Neoprene
- Leather *rarely used now
- Plaster *rarely used now
what are Low temperature thermoplastics (LTT) orthoses?
- When the plastic is malleable for molding, the temperature of the material is low enough to
be molded directly on skin without burning
what is the average temp commonly used to Low temperature thermoplastics?
160 degrees
what are high temperature thermoplastic orthoses?
Temperature is too high to be molded directly on skin; may require liner e.g. plastazote, or molding on a positive plaster model of body part
what are neoprene orthoses?
light support/allows movement that may be restricted at end ranges; can have removable stays for more/less support; can retain heat used when rigidity not tolerated or excessive padding required; often pre-fabricated
what are leather orthoses?
requires negative/positive plaster molds
time consuming
durable
what are plaster orthoses?
Used for serial static purposes
often used with neurological issues messy
extensive padding often required
what is the orthosis classification system?
- System developed by the Orthosis Classification Task Force of the
American Society of Hand Therapists for upper extremity orthoses
what is a common name for wrist/hand immobilization?
“resting hand” orthosis
what is a common name for “Wrist immobilization”?
“Wrist cock-up” Orthosis (Common name)
what is orthoses resistance to stretch?
amount that a material resists pulling or stretching
what is maximum resistance?
more control of the material, holds its shape and thickness while warm, can tolerate more aggressive handling e.g. ezeform, sansplint
what is minimum resistance?
more likely to become thin and lose its shape during the molding process, requires delicate handling, conforms to the shape of the bony part with less effort e.g. aquaplast
what is conformability or drape?
Works with gravity
Material will conform easily to body part with minimal handling
what is orthoses memory?
Ability of the material to return to its original shape with re-heating
what is high memory?
good for less experienced, more forgiving , inherent strength
of material maintained e.g. Aquaplast, sansplint
what is low memory?
modifications more difficult, more thinning of material, less strength with each occurrence of re-heating e.g. polyform
what is rigidity vs flexibility?
Amount of resistance a cold material has when a force is applied to it
what is high rigidity?
very resistive to forces, so not easily broken; useful for “hard end feel”
contractures or spasticity; usually maximum resistance to stretch when molding, thicker material
what is high flexibility?
bends easily, but may break over time if a point where it “bends” acts
like a fulcrum; usually minimum resistance to stretch, often more comfortable, thinner materials
what is edge finishing?
- Smoothing or rounding to remove sharp edges/improve cosmesis
- Can use dry heat e.g. heat gun or hot water but use caution as
overheating with either can change the “mould” you have achieved
what are self sealing edges?
A material’s ability to seal its edges as it is cut when warm
Minimize the amount of “edge finishing” required
what is the benefit of perforated material?
provides slight ventilation without compromising rigidity
what is the process of a custom orthosis?
- Assessment of needs
- Determine Orthosis purpose
- Select material
- Develop pattern
- Cut material from pattern
- Heat and mold material
- Trim and edge Orthosisc
- Apply straps
- Check fit
- Educate
