COF Upper Extremity Orthotics 3 — Questions and Answers
Question 1: A 'lumbrical bar' orthosis is PRIMARILY used to correct which deformity in a patient with ulnar nerve palsy?
- Swan neck deformity of all digits
- Claw deformity of the ring and small fingers (Correct answer)
- Boutonniere deformity of the index finger
- Mallet finger of the long finger
Correct answer: Claw deformity of the ring and small fingers
A lumbrical bar blocks MCP hyperextension, correcting the claw deformity of the ring and small fingers caused by intrinsic muscle paralysis from ulnar nerve palsy.
Question 2: Which thermoplastic material property is MOST important when fabricating a rigid protective shell for an athlete with a metacarpal fracture returning to play?
- High drapability
- High memory
- High rigidity and impact resistance (Correct answer)
- Low activation temperature
Correct answer: High rigidity and impact resistance
Rigid impact-resistant thermoplastic provides the protective shell needed to shield a healing metacarpal fracture during contact sport activity.
Question 3: The purpose of a figure-of-eight clavicle brace is to:
- Restrict shoulder abduction to 90°
- Retract the shoulders and maintain alignment of a clavicle fracture (Correct answer)
- Support the AC joint following dislocation
- Immobilize the glenohumeral joint post-dislocation
Correct answer: Retract the shoulders and maintain alignment of a clavicle fracture
A figure-of-eight brace holds the shoulders in retraction and slight elevation, maintaining alignment of a mid-shaft clavicle fracture during healing.
Question 4: For a patient with a mallet finger injury (Zone I extensor tendon rupture), the DIP joint should be immobilized in which position?
- 10–15° of flexion
- Neutral (0°) to slight hyperextension (Correct answer)
- 30° of flexion
- 45° of flexion
Correct answer: Neutral (0°) to slight hyperextension
The DIP joint is immobilized in neutral to slight hyperextension (0–5°) to approximate the ruptured extensor tendon ends and allow healing without tension.
Question 5: A dynamic MCP flexion orthosis using rubber band traction is indicated for which clinical condition?
- Acute MCP joint sprain requiring rest
- MCP extension contracture limiting grip (Correct answer)
- Rheumatoid arthritis with MCP ulnar drift
- Trigger finger in the flexor tendon
Correct answer: MCP extension contracture limiting grip
Dynamic MCP flexion orthoses apply low-load prolonged stress to remodel contracted tissue and restore MCP flexion lost due to extension contracture.
Question 6: Which rotator cuff tendon is MOST commonly torn, and which motion deficit is expected that an abduction sling orthosis addresses?
- Infraspinatus; external rotation weakness
- Subscapularis; internal rotation weakness
- Supraspinatus; shoulder abduction weakness (Correct answer)
- Teres minor; horizontal abduction weakness
Correct answer: Supraspinatus; shoulder abduction weakness
The supraspinatus is the most frequently torn rotator cuff tendon; abduction slings hold the arm in partial abduction to reduce tension on the repaired tendon.
Question 7: When evaluating orthosis fit for a patient with rheumatoid arthritis, which pressure concern is UNIQUE to this population compared with trauma patients?
- Risk of pressure sores over bony prominences only at the wrist
- Fragility of skin and joint deformity causing atypical pressure distribution (Correct answer)
- Need for higher immobilization forces due to spasticity
- Risk of compartment syndrome from tight strapping
Correct answer: Fragility of skin and joint deformity causing atypical pressure distribution
RA patients have fragile skin, osteoporotic bone, and deformed joints that create atypical contact areas, requiring extra vigilance for pressure injuries during fitting.
COF Upper Extremity Orthotics 3
A 'lumbrical bar' orthosis is PRIMARILY used to correct which deformity in a patient with ulnar nerve palsy?