In our gait laboratory, the gait pattern of 18 youths with neurogenic foot deformities as a result of spina bifida or cerebral palsy was examined. The influence of technical orthopaedic devices for the foot and ankle on kinematics and kinetics of the gait and especially of the knee joint were analyzed. Kinematic data were derived from 3D-video analysis, kinetic data from force plates and pressure distribution plates. Muscle activities were measured with eight-channel EMG. The data were examined to see if there were differences when using the technical devices. All patients had already been supported externally with the different devices like orthopaedic shoes, insoles, Nancy Hilton orthoses and orthoses for the lower leg extremity. The devices restricted to the foot and the ankle joint improved the feeling of gait stability of the patients. In this investigation, the different supports had various but little effects on the kinematics and kinetics of the knee joint, depending on the type of orthoses used and the kind of handicap of the youths. Because of the great expenditure, the data obtained in this study were taken from a small number of patients. Therefore, they are individual findings and are of restricted general significance.