Mixed Deck — All CTO Topics Flashcards

Which measurement is most important when sizing a prefabricated wrist orthosis?

Answer: Wrist circumference

Wrist circumference is the primary sizing parameter used by most prefabricated orthosis manufacturers to ensure proper fit and support.

Which thermoplastic material is most appropriate for fabricating a rigid ankle-foot orthosis (AFO) requiring high durability and resistance to deformation under load?

Answer: Polypropylene

Polypropylene is the standard rigid thermoplastic for AFOs due to its high durability, stiffness, and resistance to deformation under body weight.

Which scenario represents a violation of the Certified Orthotic Technician code of professional conduct?

Answer: Misrepresenting qualifications or certification status

Misrepresenting qualifications is a serious violation that undermines public trust.

A pediatric patient with cerebral palsy wearing a solid AFO develops a pressure sore over the navicular. The MOST appropriate immediate intervention is:

Answer: Spot heat and relieve the AFO shell directly over the navicular

Spot heating and relieving (bubbling out) the thermoplastic shell over the navicular removes direct pressure at the source of the wound.

Which muscle group is primarily responsible for controlling the rate of foot drop during the loading response phase?

Answer: Tibialis anterior

The tibialis anterior eccentrically contracts during loading response to control the rate at which the foot lowers to the ground.

Which nerve injury would most likely require a low-profile dynamic MCP extension orthosis?

Answer: Radial nerve injury at the spiral groove

Radial nerve injury at the spiral groove causes wrist drop and loss of MCP extension, requiring a dynamic orthosis to restore that function.

What does 'drop-lock' refer to in orthotic metal joint fabrication?

Answer: A ring that drops over the joint to lock it in extension, which can be unlocked for sitting

A drop-lock (ring lock) is a metal ring that slides down over the knee joint to lock it in extension, enabling stance stability while allowing removal for sitting.

When conducting a risk assessment for CTO operations, which factor should receive the HIGHEST priority?

Answer: Probability and severity of potential harm

The probability and severity of potential harm are the primary factors in risk assessment.

An adult patient fitted with a functional position hand orthosis is observed with the thumb adducted flat against the palm. The correction requires:

Answer: Adding or adjusting a C-bar or thumb post to maintain palmar abduction

A C-bar or thumb post maintains the first web space open in palmar abduction, which is essential for opposition and functional grip.

During the casting process for a custom orthosis, what does 'subtalar neutral' position mean for the foot and ankle?

Answer: The position where the subtalar joint is neither pronated nor supinated

Subtalar neutral is the position where the subtalar joint is midway between maximum pronation and supination, used as a functional reference for orthotic casting.

For a diabetic patient requiring an AFO, which liner material provides the BEST combination of pressure relief and moisture management?

Answer: Plastazote (polyethylene foam)

Plastazote is heat-moldable, pressure-distributing, and lightweight, making it the preferred liner for insensate diabetic feet at risk for skin breakdown.

What is the primary advantage of carbon fiber composite over polypropylene for orthotic fabrication?

Answer: Higher strength-to-weight ratio

Carbon fiber composites offer superior strength-to-weight ratio, allowing for lighter, thinner orthoses with equivalent or greater rigidity.

What tool is commonly used to make precise device adjustments?

Answer: Heat gun or oven

Many orthotic devices are made from thermoplastic materials that can be molded and reshaped when heated. A heat gun or oven provides controlled heat, allowing the Certified Orthotic Technician to soften these materials and make precise adjustments to the device's shape, contours, or angles. This capability is essential for customizing the orthotic to the patient's unique anatomy and addressing specific pressure points or functional requirements.

What is the MOST effective way for new CTO professionals to build competency?

Answer: Combining formal education, mentored practice, and ongoing professional development

Building competency requires formal education, mentored practice, and ongoing development.

Which material is commonly used for making lightweight orthotic devices?

Answer: Polypropylene

Polypropylene is a thermoplastic polymer widely favored in orthotic fabrication due to its excellent combination of properties. It is lightweight, durable, and can be easily heat-molded to create custom orthotic devices that are comfortable and functional for patients. Its versatility makes it ideal for various applications, from ankle-foot orthoses to spinal braces.

What ground reaction force direction must pass anterior to the knee joint to produce a knee extension moment?

Answer: Anterior

When the ground reaction force vector passes anterior to the knee joint center, it creates an external knee extension moment.

A 'lumbrical bar' component added to an orthosis addresses which deformity?

Answer: Intrinsic minus (claw hand) deformity

A lumbrical bar blocks MCP joint hyperextension, counteracting the intrinsic minus claw hand deformity seen in ulnar or combined nerve injuries.

A solid ankle AFO is most appropriate for a patient with which condition?

Answer: Foot drop with spasticity requiring control in multiple planes

A solid ankle AFO is indicated for foot drop with spasticity because it controls sagittal, frontal, and transverse plane motion simultaneously.

What is the primary function of the subtalar joint during gait?

Answer: Inversion and eversion to absorb shock and adapt to terrain

The subtalar joint performs inversion and eversion to absorb shock and allow the foot to adapt to uneven terrain during gait.

A patient returns with a custom foot orthosis (CFO) complaining that it slides forward in the shoe. The MOST effective solution is:

Answer: Check shoe fit and recommend a shoe with a firm heel counter

A firm heel counter in the shoe holds the heel in place, preventing the orthosis and foot from sliding forward during gait.