Abstract
A system is developed to measure various functions of the artificial leg continuously for long periods under any walking conditions. The system is composed of two parts. One is a measuring subsystem of portable size, movable anywhere with the subject, and the other is a data processing subsystem located in the laboratory. The measuring subsystem is constructed from a pylon load cell installed in the shank part of an artificial leg to measure six quantity forces, and flexible electrogoniometers attached on each side of bilateral hip, knee and ankle joints. This goniometer is made of electro-conductive silicone rubber mounted on an elastic rubber beam which is self-aligning, very light weight and compact. Very large time series data obtained by the measuring subsystem is processed efficiently in a relatively short time by the data processing subsystem constructed from the interactive graphic terminal connected to the minicomputer. With this monitoring system, the dynamic alignment of below-knee prostheses was measured. Some of the quantitative relations between the displacement of the foot to anteriorposterior or medial-lateral directions in the horizontal plane, and patterns of load on each part of the prosthesis and/or angles of both side joints were examined. Minute information about the behavior of each part of the lower limbs has been attained, which could not be obtained by previous studies measuring the locus of the gravity center or other macro parameters. This knowledge gives a concrete base for the best dynamic alignment of an artificial leg for individual amputees.
