摘要
The development of a device and the derivation of a trigonometric solution that permits direct determination of wrist angular displacement in the flexion/extension and radial/ulnar planes is presented. System performance was quantified during a bench evaluation, and by comparison to an electromagnetic tracking system during a wrist-mounted evaluation with 16 subjects. The wrist-mounted evaluation was repeated with nine subjects to evaluate repeatability of the measurement system. The results indicate that the differences between angular displacement calculated using the goniometer were not significantly different from the calibration stand, with errors of 0.70±0.64° in the flexion/extension plane and 0.66±0.68° in the radial/ulnar deviation plane. In a wrist-mounted evaluation of the goniometer with the electromagnetic tracking system, errors of 0.59±0.51° and 0.89±0.95°, respectively, were found. Linear regression was used to determine the slope and intercept of the relationship between the goniometer and the electromagnetic tracking system for the nine subjects who repeated the evaluation. Paired t-tests for means found no significant differences (p<0.05) for the slopes and intercepts of the repeated measures. The results suggest that the proposed device and algorithm provide an accurate measurement of wrist angular displacement in two planes, with a minimum of preparation or calibration. Relevance to industry Determination of wrist posture and angular displacement are important components of a comprehensive ergonomic evaluation. An accurate and easily applied goniometer has been developed and described. © 2004 Elsevier B.V. All rights reserved.