Prosthetic & Orthotic Design & Fabrication Flashcards

Which characteristic of Surlyn (ionomer resin) makes it particularly useful as a check socket material for early prosthetic fitting?

Answer: It is transparent, allowing visual assessment of tissue contact

Surlyn's transparency allows the clinician to visually inspect skin contact, blanching, and pressure distribution through the socket wall during fitting.

For a patient with a high transfemoral amputation and very short residual limb, which socket design modification is most important to ensure adequate suspension and control?

Answer: Extended proximal brim with hip joint and pelvic band

A very short residual limb provides minimal lever arm control, so extending the socket with a hip joint and pelvic band captures hip motion and improves stability.

In custom spinal orthosis fabrication, the material most commonly used for the rigid shell due to its balance of strength, light weight, and moldability is:

Answer: Polypropylene

Polypropylene is preferred for rigid spinal orthosis shells because it can be heat-formed to custom shapes, offers good strength-to-weight ratio, and is easily trimmed.

A patient with a transradial amputation reports that their body-powered prosthesis terminal device opens too slowly and requires excessive effort. The most likely adjustment is to:

Answer: Increase cable excursion by adjusting the harness or control attachment point

Insufficient terminal device opening is often due to inadequate cable excursion; adjusting the harness attachment or control point increases the range of cable travel.

When fabricating a scoliosis orthosis (e.g., Boston brace), the pad placement over the primary lumbar curve is positioned to apply force:

Answer: Laterally at the apex of the curve on the convex side

Lateral corrective pads are placed on the convex side at the curve apex to apply a medially directed force that reduces the lateral deviation.

Which fabrication technique is used to create a definitive prosthetic socket that allows selective stiffness variation, with flexible areas at muscle bellies and rigid areas at bony prominences?

Answer: Flexible socket within a rigid frame using co-lamination

Co-laminating a flexible polyethylene liner within a rigid carbon or acrylic outer frame allows targeted flexibility and rigidity in the same socket.

The SACH (Solid Ankle Cushion Heel) foot is most appropriate for which patient profile?

Answer: Low-activity patients requiring durability, simplicity, and low maintenance

The SACH foot's simple design with a cushioned heel is ideal for low-activity users due to its durability, low cost, and minimal maintenance requirements.