COF Materials & Fabrication Basics 2

Question 1

Which thermoplastic material is most commonly used for ankle-foot orthoses (AFOs) due to its balance of rigidity and workability?

Accepted Answer

Polypropylene

Answer

Polypropylene is the most widely used thermoplastic for AFOs because it offers good rigidity, fatigue resistance, and is easy to heat-form and trim.

Question 2

At approximately what temperature (°F) does low-temperature thermoplastic become moldable for direct patient fitting?

Accepted Answer

140–180°F

Answer

Low-temperature thermoplastics soften between 140–180°F, allowing them to be molded directly on or near the patient without risk of burns.

Question 3

What property describes a material's ability to return to its original shape after the deforming force is removed?

Accepted Answer

Elasticity

Answer

Elasticity is the property that allows a material to recover its original shape after stress is removed, which is important for dynamic orthotic components.

Question 4

Which metal alloy is preferred for orthotic uprights when lightweight construction is a primary concern?

Accepted Answer

Aluminum alloy

Answer

Aluminum alloy is preferred when weight reduction is critical because it is significantly lighter than steel while still providing adequate strength for most orthotic applications.

Question 5

What is the primary advantage of closed-cell foam over open-cell foam in orthotic padding?

Accepted Answer

Better moisture resistance

Answer

Closed-cell foam resists moisture absorption, making it more hygienic and durable in environments where sweat or water exposure is expected.

(COF) Certified Orthotic Fitter Practice Test

(COF) Certified Orthotic Fitter Practice Test

COF Materials & Fabrication Basics 2