The Effect of Transient Loading on a Foot-Orthotic Using Temporal Parameters of Gait

Abstract

This study describes a method for performing transient finite element analysis (FEA) of an assistive device using experimental parameters obtained from gait analysis. A subject displaying pathologic gait, owing to lower limb deformity, was chosen for gait study. Using CAD tools, a remedial orthotic device was designed, which is expected to improve the gait of the subject. The orthotic model was subjected to static and transient loading conditions obtained from gait study, using an FEA tool. The stress ‘hot’ zones between the two modes of analysis are studied. In addition, the experimental gait data of a healthy control group were recorded to perform univariate regression studies for predicting the peak values of the normal forces, and validated by comparing with those available in the literature. The values thus obtained may be used for static behavioral analysis of assistive devices. From the FEA results, it can be conclusively said that the orthotic model is capable of sustaining gait cycle loading. The regression studies suggest the possibility of using anthropometric data to predict gait forces and subsequently perform static and transient loading analysis of assistive devices.

Experimental and numerical investigation of a polypropylene orthotic device for assistance in level ground walking

“…The assistive device can fill the gap between the heel and the ground whereby the spring action of the device shall allow desirable flexion at the ankle joint. 10 The angle between the upper and lower leaflet may be decreased gradually with progression in rehabilitation therapy until finally the insert may be removed. A limitation of this study is that the subjects did not have muscle spasticity or other gait disorders, and hence the gait patterns from actual subjects with pathology may vary.…”

“…The biomechanical effects of remedial prosthetic and orthotic devices have also been extensively studied with the use of motion analysis, to understand the extent of the remedy provided by these devices. [6][7][8][9][10][11] The fabrication and use of the commonly used ankle-foot orthoses (AFOs) and in-shoe orthoses have been outlined by Beitl and Noll 9 and the benefits of technology in designing better assistive devices have been advocated. Majumdar et al 11 discussed the cons of using prefabricated orthoses and proposed novel custom orthoses that reduce the rearfoot pronation.…”

“…Majumdar et al 11 discussed the cons of using prefabricated orthoses and proposed novel custom orthoses that reduce the rearfoot pronation. A recent study by Jena et al 10 utilised computer-aided design (CAD) and transient loading analysis to compare the resulting mechanical behaviour of a conceptual orthotic device with traditional static loading methods. The study by Curtze et al 6 showed that an inverted pendulum apparatus can be used in a typical gait laboratory to study the biomechanical performance of various prosthetic feet by comparing the rollover shapes.…”

“…This device is intended for individuals lacking the heelstrike phase during a gait cycle which is a commonly observed symptom for various gait-related pathologies. 2,10 The orthosis has been designed in such a way that it bridges the gap between the plantar heel and the ground surface. This causes the line of action of force to move through the ankle joint while allowing flexibility at the ankle joint.…”

“…This causes the line of action of force to move through the ankle joint while allowing flexibility at the ankle joint. 10 The leaf-spring action of this device shall provide the user with a gradual extension of the calf muscles during the gait cycle, as opposed to rigid wedge orthotic inserts. Multiple studies have reported the use of trials with healthy participants to perform an initial assessment before proceeding with clinical trials.…”