Question

Identify reasons to provide serial orthotic intervention with wrist immobilization orthoses

Answer 1

An orthosis is an externally applied device that is designed and fitted to the body to achieve one or more of the following goals:

• Control biomechanical alignment
• Prevent or correct or accommodate deformity
• Protect and support an injury
• Assist rehabilitation
• Reduce pain
• Increase mobility
• Increase independence
• Stabilize, position or immobilize a body part

Reasons to provide serial orthotic intervention with wrist immobilization orthoses include:

• The wrist will act as the keystone for hand positioning and outlines the basis for all splinting, except isolated digital splinting.
• The weight of the immobile hand, gravity, and resting muscle tension tend to pull the wrist into flexion, which increases tension in the extrinsic extensor tendons, pulling the metacarpophalangeal (MCP) joints into hyperextension.

1. The metacarpophalangeal joints (MCP) joint is the key for finger function.
2. When MCP joints are hyperextended, the IP joints flex because of the tension of the flexors and the delicate balance between the finger extensors and flexors.
3. Extension stability of the wrist is important for optimal function of the hand.
4. The wrist should also be placed in slight extension to maintain flexor tendon length and to improve hand function
5. This position will place the MCP collateral ligaments on maximum stretch, preserve the anatomic arches of the hand and thus oppose the development of a “claw hand” deformity.
6. This position is also referred to as the ”safe” or “intrinsic plus.
7. This position fosters the weaker intrinsic motions of the MCP flexion and IP extension that are difficult to obtain.

• Concurrently, the tension of the extrinsic flexor is maintained while forcing the interphalangeal (IP) joints (which include the proximal interphalangeal [PIP] and distal interphalangeal [DIP] joints) into flexion.
• The metacarpal arch of the hand flattens and the thumb falls into adduction.
• This results in a “claw hand” that is not functional.
• Prevention of this deformity is one goal of hand splinting.

Wrist Function: -

1. Good hand function dependent on ability of wrist to position hand in stable manner.
2. - Position of wrist changes according to functional task presented to hand.
3. - When task requires power + strength, position of wrist is extension + radial deviation.
4. - When task requires fine precision, wrist assumes position of slight flexion & ulnar deviation.
5. Wrist Minimum criteria for function without equipment: ROM: - 0º - 45º flexion (PROM) - 0º - 45º extension (PROM) Strength: - Minimum of F+ (3+) wrist extension required to counteract action of finger muscles involved in grasp & pinch.
6. Motion- Controlled & isolated motion required for fine precision.