Auto-Lock and Motorized Device for the Knee Joint of Long Leg Brace; Development and Performance Test

ABSTRACT

OBJECTIVE: To develop and evaluate a new orthotic device for the knee to improve the ambulation patterns in paraplegic patients. METHOD: The new orthotic device combined a high torque servo motor with a bail-lock knee joint, and a its wireless controller adopting open-loop control system. The device was tried in a paraplegic volunteer for two months, simultaneously with the conventional long leg brace. RESULTS: The new device could keep the orthotic knee joint exended during the stance phase, and allow the sequential flexion and extension of the joint during the swing phase. The new orthotic device provided both longer step length(p<0.05) and fewer cadence(p<0.05) maintaining the same walking speed. Also, a circumduction during the swing phase reduced, and the posture of the trunk became straighter. The stride time and the double support period became longer(p<0.05), and the magnitude of the shift of pelvic center increased(p<0.05). CONCLUSION: The new orthotic device for the knee was developed and evaluated in a paraplegic volunteers who had failed to use the functional electrical stimulation. The results were satisfactory with a probable lower energy efficiency with the new orthosis. Further study for verification of the results seems to be necessary.