[Possibilities for quantitative gait analysis in evaluation of prosthesis fit]

Nowadays, the fitting of a lower-limb prosthesis is done mainly on an empirical basis. The main aim of the present study was to provide objective data and presentations to support the subjective data. With the aid of a cybernetic statement, the process of fitting a prosthesis to a human subject was developed as a self-optimizing control cycle. Using this systematic scheme, the walking trial was identified as the process element of this control cycle in which the fitting proper took place. Starting with this systematic scheme, the characteristics of defined changes to the system human-prosthesis during walking were measured with the aid of a specially configured gait analysis system. For the estimation of the characteristics of the measured walking trial, a three stage parameter system based initially only on the angle, velocity and acceleration curves at the knee joint was developed. On the basis of pattern recognition routines, the parameter system permits a very high level of identification of the measurements. The identification of poor fittings not covered by the pattern recognition system is not yet satisfactory. However, with the incorporation of additional gait parameters, it will be possible to further improve the description of the gait, enabling better recognition of disturbances in the human-prosthesis system.