CPO Prosthetic & Orthotic Design & Fabrication 2

Question 1

Which thermoforming technique is most appropriate for fabricating a total contact orthosis requiring high conformity to bony prominences?

Accepted Answer

Vacuum forming over a positive model

Answer

Vacuum forming over a positive model applies uniform negative pressure to draw the heated thermoplastic into intimate contact with all surface contours.

Question 2

A patient with a transfemoral amputation has a residual limb that has decreased in volume significantly post-surgery. Which socket modification is the FIRST step to address this?

Accepted Answer

Add distal padding or liner inserts

Answer

Adding distal padding or liner inserts compensates for volume loss and restores fit without the expense and time of fabricating a new socket.

Question 3

In carbon fiber laminate fabrication, the direction of fiber orientation most critical for maximizing longitudinal stiffness in a pylon is:

Accepted Answer

0° (parallel to long axis)

Answer

Fibers oriented at 0° (parallel to the long axis) bear axial loads most efficiently, maximizing longitudinal stiffness.

Question 4

When casting a patient for a below-knee orthosis, the subtalar joint should ideally be positioned in:

Accepted Answer

Neutral subtalar position

Answer

Casting in subtalar neutral captures the foot in its most biomechanically efficient alignment, which is the goal for most AFO designs.

Question 5

Which material property makes high-density polyethylene (HDPE) preferable over polypropylene for a patient requiring frequent impact loading in a lower-limb orthosis?

Accepted Answer

Higher impact resistance and toughness

Answer

HDPE's higher impact resistance and toughness make it better able to absorb repeated impact loads without fracture compared to polypropylene.

(CPO) Certified Prosthetist Orthotist Practice Test

(CPO) Certified Prosthetist Orthotist Practice Test

CPO Prosthetic & Orthotic Design & Fabrication 2