Which orthotic design is appropriate to improve functional use of the hand in radial nerve palsy?

• A. Forearm-based, radial thumb spica which supports the lateral aspect of the wrist and hand
• B. Forearm-based wrist orthotic that maintains the wrist in 30° of extension
• C. Anti-claw orthosis
• D. Hand-based short thumb spica

Answer: (B)

Radial nerve palsy causes wrist drop, so the hand’s function is often most improved by a compensatory position that uses the intact finger flexors. Holding the wrist in slight extension, about 30 degrees, creates a lengthened, advantageous position for the finger flexors to generate a functional grasp through the tenodesis effect. A forearm-based wrist orthosis that maintains that extension provides a stable platform for the hand to grasp and release objects with minimal active wrist movement, which is exactly the functional goal in radial nerve palsy.

Other designs don’t optimize this mechanism: a hand- or thumb-spica that immobilizes the thumb or other digits, or an anti-claw orthosis aimed at different nerve injuries, won’t specifically enhance functional grasp via tenodesis in radial nerve palsy.