Prosthetic & Orthotic Design & Fabrication Flashcards

In the fabrication of a patellar tendon bearing (PTB) transtibial socket, the area over the fibular head should be:

Answer: Relieved to avoid peroneal nerve compression

The fibular head area must be relieved in the PTB socket to prevent compression of the superficial peroneal nerve and subsequent neuropathy.

Which joint design in a knee-ankle-foot orthosis (KAFO) allows for free motion during swing phase while providing stance-phase stability?

Answer: Stance control (SCKAFO) orthotic knee joint

Stance control KAFO joints automatically lock during weight acceptance and unlock during swing to allow free knee flexion and improve gait efficiency.

The primary advantage of using a flexible inner socket within a rigid outer frame (flexible socket design) for transfemoral amputees is:

Answer: Improved comfort and tissue accommodation during dynamic activity

The flexible inner socket (typically polyethylene) conforms to soft tissue changes during activity, improving comfort and reducing pressure peaks.

When fabricating a TLSO for scoliosis management, the three-point pressure system primarily works by applying corrective force at the:

Answer: Apex of the curve and two counter-pressure points above and below

The three-point system applies a primary corrective force at the curve apex with reciprocal counter-forces above and below to produce lateral correction.

What is the correct sequence for laminating a carbon fiber prosthetic socket using wet lay-up technique?

Answer: Apply resin to fabric layers, lay over positive model, apply vacuum, cure

Wet lay-up involves saturating reinforcement fabric with resin, draping it over the model, applying vacuum for consolidation, and then allowing cure.

Which suspension mechanism is contraindicated in a patient with a transfemoral amputation who has significant skin integrity issues on the distal residual limb?

Answer: Suction socket with distal one-way valve

Suction suspension concentrates shear and normal forces at the distal residual limb, which can exacerbate existing skin integrity problems.

For fabricating a custom foot orthosis to address plantar fasciitis, the posting strategy that best offloads the medial heel is:

Answer: Medial heel skive with rearfoot varus post

A medial heel skive combined with a rearfoot varus post supinates the subtalar joint and reduces tension on the plantar fascia insertion.