CTO Upper Extremity Orthotics 2 — Questions and Answers
Question 1: After reduction of a posterior elbow dislocation, an orthosis typically restricts which motion to prevent re-dislocation?
- Full flexion beyond 90 degrees
- Terminal extension (Correct answer)
- Forearm pronation and supination
- Wrist flexion and extension
Correct answer: Terminal extension
Restricting terminal elbow extension prevents the humeral-ulnar joint from re-dislocating posteriorly while allowing functional range of motion.
Question 2: For a patient with radial nerve palsy, a dynamic wrist orthosis typically supports the wrist in approximately how many degrees of extension?
- 0–10 degrees
- 15–20 degrees
- 30–45 degrees (Correct answer)
- 60–75 degrees
Correct answer: 30–45 degrees
Positioning the wrist in 30–45 degrees of extension optimizes tenodesis and power grip function in radial nerve palsy.
Question 3: A 'lumbrical bar' component added to an orthosis addresses which deformity?
- Swan neck deformity
- Boutonnière deformity
- Intrinsic minus (claw hand) deformity (Correct answer)
- Mallet finger deformity
Correct 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.
Question 4: To maximize mechanical efficiency in a dynamic finger extension orthosis, the outrigger should be positioned so the line of pull is at what angle relative to the middle segment of the finger?
- 45 degrees
- 60 degrees
- 90 degrees (Correct answer)
- Parallel to the long axis
Correct answer: 90 degrees
A 90-degree angle of pull to the proximal segment of the finger being mobilized generates maximum rotational force with minimal translational force.
Question 5: A static progressive orthosis differs from a dynamic orthosis primarily because it:
- Uses rubber bands instead of springs
- Uses inelastic components that are manually adjusted at treatment intervals (Correct answer)
- Is only used for acute traumatic injuries
- Cannot generate enough force to address joint contractures
Correct answer: Uses inelastic components that are manually adjusted at treatment intervals
Static progressive orthoses use non-elastic components (screws, straps, hinges) that are incrementally adjusted as tissue lengthens, delivering a sustained low-load stretch.
Question 6: Which orthosis design is most appropriate for a patient with median nerve injury at the wrist presenting with thenar muscle weakness?
- Opponens orthosis (Correct answer)
- Wrist cock-up orthosis
- Full resting hand orthosis
- Dynamic MCP flexion orthosis
Correct answer: Opponens orthosis
An opponens orthosis positions the thumb in palmar abduction and opposition to compensate for thenar muscle paralysis from median nerve injury.
Question 7: Compared to a volar wrist orthosis, a dorsal wrist orthosis design primarily benefits patients by:
- Providing greater wrist extension force
- Leaving the palm free for sensory tasks and object manipulation (Correct answer)
- Reducing overall device weight significantly
- Offering superior cosmetic appearance
Correct answer: Leaving the palm free for sensory tasks and object manipulation
A dorsal design leaves the volar surface of the hand unobstructed, preserving palmar sensation and the ability to perform tactile discrimination tasks.
CTO Upper Extremity Orthotics 2
After reduction of a posterior elbow dislocation, an orthosis typically restricts which motion to prevent re-dislocation?