CTO Patient Evaluation & Measurement 5 — Questions and Answers
Question 1: When taking circumferential measurements of the lower extremity for a custom KAFO, at which anatomical reference point is the thigh measurement recorded as the 'maximum thigh circumference'?
- 5 cm below the ischial tuberosity
- At the widest girth of the thigh (Correct answer)
- At mid-femur calculated from greater trochanter to lateral joint line
- Just proximal to the patella
Correct answer: At the widest girth of the thigh
Maximum thigh circumference is measured at the widest point of the thigh, which defines the upper boundary for the proximal thigh cuff of the KAFO.
Question 2: A technician observes that a patient's knee recurvatum reaches 15° during stance phase. Which orthotic intervention would directly address this finding?
- Solid AFO set in 5° plantar flexion
- Solid AFO set in 5° dorsiflexion (Correct answer)
- Free-motion AFO with posterior trim line
- CROW boot with rocker sole
Correct answer: Solid AFO set in 5° dorsiflexion
An AFO set in dorsiflexion creates an anterior tibial progression force that blocks knee hyperextension (recurvatum) during stance.
Question 3: During the initial evaluation for a scoliosis TLSO, the apical vertebra of the curve is at T9. The pad placement on the orthosis that directly addresses the primary curve correction should be located:
- At the same level as the apical vertebra on the convex side (Correct answer)
- Two vertebral levels above the apex on the concave side
- At the end vertebra of the curve on the concave side
- At L3 regardless of curve apex for pelvic anchoring
Correct answer: At the same level as the apical vertebra on the convex side
The lateral corrective pad is placed directly at the apex on the convex side of the curve to apply the primary three-point corrective force.
Question 4: A patient undergoing evaluation for an upper-extremity orthosis post-stroke exhibits wrist drop. Measurement of active wrist extension reveals 0° of motion. What is the priority measurement for fabricating a functional resting splint?
- Active grip strength in kilograms
- Passive range of motion of wrist extension (Correct answer)
- Two-point discrimination of the palm
- Elbow flexion angle at rest
Correct answer: Passive range of motion of wrist extension
Passive wrist extension ROM determines the functional position achievable without overstretching structures, guiding the wrist angle set in the fabricated splint.
Question 5: A custom-molded shoe insert is being fabricated for a patient with a flexible flatfoot. Which measurement quantifies the talar head coverage that determines the medial arch support height?
- Navicular drop test value (Correct answer)
- Arch index from pedobarograph
- First ray plantar flexion range
- Heel bisection angle on standing X-ray
Correct answer: Navicular drop test value
The navicular drop test measures how far the navicular falls from subtalar neutral to relaxed standing, quantifying medial arch collapse and guiding arch support height selection.
Question 6: When evaluating a patient for a functional electrical stimulation (FES) orthosis for foot drop, which assessment is performed to determine candidacy based on peripheral nerve integrity?
- Manual muscle testing of tibialis anterior
- Nerve conduction study of the common peroneal nerve (Correct answer)
- Semmes-Weinstein monofilament threshold testing
- Electromyographic assessment of gastrocnemius activity
Correct answer: Nerve conduction study of the common peroneal nerve
FES requires an intact peripheral motor nerve to generate muscle contraction; nerve conduction study of the common peroneal nerve confirms lower motor neuron pathway integrity.
Question 7: During measurement for an elbow orthosis, the anatomical axis of the elbow is identified for joint alignment. This axis passes through which structures?
- The olecranon process and coronoid process
- The medial and lateral epicondyles of the humerus (Correct answer)
- The radial head and ulnar styloid
- The capitellum and the olecranon fossa
Correct answer: The medial and lateral epicondyles of the humerus
The flexion-extension axis of the elbow passes through the medial and lateral epicondyles of the humerus, and orthotic joints must be aligned to this axis to prevent migration.
CTO Patient Evaluation & Measurement 5
When taking circumferential measurements of the lower extremity for a custom KAFO, at which anatomical reference point is the thigh measurement recorded as the 'maximum thigh circumference'?