CO Materials Science & Fabrication Techniques Flashcards

In orthotic fabrication, 'posting' refers to:

Answer: Wedging the heel or forefoot of an orthosis to alter rearfoot or forefoot alignment

Posting involves adding wedge-shaped material to the heel or forefoot of an orthosis to tilt the foot and correct rearfoot varus/valgus or forefoot imbalances.

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

Answer: Elasticity

Elasticity is the property by which a material recovers its original shape after stress is removed, which is critical for dynamic orthotic components like energy-storing footplates.

A 'total contact cast' (TCC) achieves pressure redistribution for diabetic foot ulcers primarily by:

Answer: Distributing plantar pressure over the entire plantar surface of the foot and lower leg

A TCC distributes weight-bearing pressure over the entire plantar surface and into the lower leg walls of the cast, dramatically reducing peak pressure at the ulcer site.

Titanium is sometimes selected over stainless steel for orthotic uprights because it offers:

Answer: Similar strength with significantly reduced weight

Titanium provides strength comparable to stainless steel at roughly 45% less weight, making it advantageous for patients where device weight is a significant concern.

When fabricating a TLSO using the vacuum-forming technique, the orthotist must ensure the positive model is modified to account for soft tissue compression. This modification is known as:

Answer: Rectification

Rectification involves modifying the positive model by building up or removing plaster in key areas to account for how soft tissue will compress under the orthosis and to incorporate desired corrections.

Which lamination resin is most resistant to UV degradation and chemical exposure, making it suitable for orthoses worn in outdoor environments?

Answer: Epoxy resin

Epoxy resins offer superior resistance to UV radiation and chemical exposure compared to polyester or acrylic resins, making them the preferred choice for orthoses in demanding environments.