Vibration Analysis and Measurement in Knee Ankle Foot Orthosis for Both Metal and Plastic KAFO Type

Abstract

A standard knee-ankle-foot orthosis (KAFO) is typically prescribed to support the limb during locomotion, during which (KAFO) is used for people with isolated quadriceps weakness or paralysis. In this paper the measurement applied on girl undergoing palsy children in her left leg as a case study. The first pathological concern is of age, weight, length and the residual palsy limb of 30 years old, 59kg, 156 cm, and 76 cm respectively, while the second test done is on man suffering flexion knee and shorten left leg due to injection by a needle in a wrong position when he was a child. The pathological concern is of age, weight, length and the residual defect limb of 35years, 82kg, 172 cm, and 80 cm respectively. This work involves two major parts: the first of which is the experimental part to measure the ground reaction force for both healthy and intake legs. The interface pressure between leg and calf part is measured for twelve points covering the total KAFO surface area, while the vibration data (velocity, acceleration and frequency) are measured at the last stage for the patient at different positions during the gait cycle. The second part is the numerical part during which stresses is calculated using ANSYS software for two cases, the first one is calculating stresses due to IP loading condition, while the second is calculating stresses due to the harmonic and spectrum vibration type. The above procedures were used for two types of KAFO, the first one is for metal-metal KAFO type and the second is for the plastic-metal KAFO type. The result shows that the GRF for the healthy person limb is greater than that of the intake person limb in about (17 %) while the healthy limb has GRF lesser than that of the intake limb for the same person in (2.2%). The Maximum IP is recorded in the posterior regions in the thigh part with (51Kpa). The result shows that the maximum Vibration data is in the sensing position at the knee on (8.5 and 5.9)for acceleration and frequency respectively at knee region for the plastic-metal KAFO type. Using plastic-metal KAFO type also leads to reduce the vibration data on (6.4% and 26%) for both acceleration and frequency respectively at thigh region.