Video-computer quantitative evaluation of thumb function using workspace of the thumb.

This study develops the basis for video-computer quantitative evaluation method for measuring degree of thumb impairment. The system evaluates the three-dimensional space (workspace) within which the thumb-tip moves and computes its surface area. This study is intended to be the basis of a subsequent study which will compute the percentage of actual use compared to the "ideal" value for the given thumb length. Based on this quantitative measurement, the movement function of the impaired thumb can be identified objectively. Repeatability testing confirms that the video motion analysis system is a reliable tool for measuring the workspace of thumb-tip motion. It is also shown experimentally that there is a linear correlation between the surface area of thumb-tip motion workspace and the square of the thumb length. Accordingly, this method may be used to evaluate the functional abnormalities and deformities of the thumb.