Orthoses Thermoplastics & Terminology

Question 1

what are different types of orthosis materials?

Answer 1

• Low temperature thermoplastics (LTT)
• High Temperature thermoplastics
• Neoprene
• Leather *rarely used now
• Plaster *rarely used now

Question 2

what are Low temperature thermoplastics (LTT) orthoses?

Answer 2

• When the plastic is malleable for molding, the temperature of the material is low enough to
  be molded directly on skin without burning

Question 3

what is the average temp commonly used to Low temperature thermoplastics?

Answer 3

160 degrees

Question 4

what are high temperature thermoplastic orthoses?

Answer 4

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

Question 5

what are neoprene orthoses?

Answer 5

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

Question 6

what are leather orthoses?

Answer 6

requires negative/positive plaster molds

time consuming

durable

Question 7

what are plaster orthoses?

Answer 7

Used for serial static purposes
often used with neurological issues messy
extensive padding often required

Question 8

what is the orthosis classification system?

Answer 8

• System developed by the Orthosis Classification Task Force of the
  American Society of Hand Therapists for upper extremity orthoses

Question 9

what is a common name for wrist/hand immobilization?

Answer 9

“resting hand” orthosis

Question 10

what is a common name for “Wrist immobilization”?

Answer 10

“Wrist cock-up” Orthosis (Common name)

Question 11

what is orthoses resistance to stretch?

Answer 11

amount that a material resists pulling or stretching

Question 12

what is maximum resistance?

Answer 12

more control of the material, holds its shape and thickness while warm, can tolerate more aggressive handling e.g. ezeform, sansplint

Question 13

what is minimum resistance?

Answer 13

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

Question 14

what is conformability or drape?

Answer 14

Works with gravity

Material will conform easily to body part with minimal handling

Question 15

what is orthoses memory?

Answer 15

Ability of the material to return to its original shape with re-heating

Question 16

what is high memory?

Answer 16

good for less experienced, more forgiving , inherent strength
of material maintained e.g. Aquaplast, sansplint

Question 17

what is low memory?

Answer 17

modifications more difficult, more thinning of material, less strength with each occurrence of re-heating e.g. polyform

Question 18

what is rigidity vs flexibility?

Answer 18

Amount of resistance a cold material has when a force is applied to it

Question 19

what is high rigidity?

Answer 19

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

Question 20

what is high flexibility?

Answer 20

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

Question 21

what is edge finishing?

Answer 21

• 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

Question 22

what are self sealing edges?

Answer 22

A material’s ability to seal its edges as it is cut when warm

Minimize the amount of “edge finishing” required

Question 23

what is the benefit of perforated material?

Answer 23

provides slight ventilation without compromising rigidity

Question 24

what is the process of a custom orthosis?

Answer 24

• 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