Compensatory Motion caused by Forearm Restriction while Turning a Steering Wheel for Transradial Prosthetic Design

Stephanie L. Carey1, M. Jason Highsmith, and Rajiv Dubey

ABSTRACT: Poor function of a transradial prosthesis lacking a dynamic wrist component may cause awkward compensatory motion. The purpose of this study was to determine if the shoulder or elbow of the unaffected or affected upper limb compensates for the restriction of the wrist and forearm simulating a basic myoelectric transradial prosthesis while turning a steering wheel. Ten non-amputee subjects volunteered for this study. Using a Vicon motion analysis system, the subjects’ upper limb movements were recorded while turning a steering wheel. This right turn was repeated with the subjects braced on the dominant (right) side restricting wrist and forearm movement. The range of the shoulder and elbow joint of the right and left sides were determined. A degree of asymmetry between the right and left arm was calculated. A repeated measure analysis of variance was calculated for each outcome measure comparing the non- braced (N-BR) and braced (BR) conditions. There were significant differences in the range of shoulder flexion and elbow flexion on right and left sides and in the degree of asymmetry. These findings suggest while turning a steering wheel, the braced or transradial prosthesis simulated side requires a greater range of motion in the sagittal plane of the shoulder and the elbow. This greater range of motion necessary should be considered in transradial prosthetic design.

KEYWORDS: Compensatory Motion, Turning Task, Transradial Prosthesis

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