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

Abstract

This study investigates the use of an orthotic device for improving pathologic gait lacking a heel-strike and its effect on the joint loads. The orthosis is fabricated from 10-mm thick polypropylene sheets joined together using a bolted joint. The gait trials are recorded using a Qualisys motion capture system and Kistler’s force platform. The data recorded in this study comprise five male and five female participants, executing level ground gait under barefoot, shod and orthotic conditions. Computed tomography reconstructed foot bone–tissue model and computer-aided design model of the orthosis are used to predict the mechanical behaviour with and without orthosis under static loading. A one-way analysis of variance is conducted to compare the peak gait parameters in the early and late stance phase between the three walking conditions. The experimental results show that the orthosis reduces the peak joint forces and the rate of change of moment at the hip, knee and ankle joints. The finite element analysis results present a decrease in foot plantar pressure from 0.74 to 0.32 MPa with orthotic usage. The results of this study indicate that the orthosis can eliminate the heel-ground gap while retaining sufficient ankle motion and providing peak joint force reduction.

Investigate the Effect of Using an Adaptable Orthosis with Airbag Cushion as an Arch Support for Flatfoot Treatment

“…Depending on the previous studies, orthosis that use Polypropylene provide good results with less stress and deformation, also it have a good safety factor, (13,14) low cost, (15) also it has a significant favorable effect on the joint kinetics of gait during level ground walking (13,14) and improve the pressure distribution. (16) The base was covered by Plastazote sheet that shown in the figure 8 since this thermoplastic polyethene foam moulds itself to the contours of the foot when walking to give a relief and cushions pressure areas of the foot, (7) also it helps in reducing the pressure distribution, sheer force and braking force. (17) Secondly, we cover the cast with Nylon to form a protective layer from humidity, dust, heat, and to remove the annealed sheet from the cast after the forming process.…”

A novel 3D printed personalised insole for improvement of flat foot arch compression and recoil – preliminary study

“…16,17 Moreover, CAD models are perfectly suited for numerical simulation to assess the effectiveness of the shoe insole regarding its mechanical behaviour under different loading conditions or in different shoe geometries. 16,18,19 In a recent development, Hu et al 20 proposed an integrated procedure that utilises preliminary assessment, design and testing. However, this procedure does not still resolve the outstanding issue, that is, how to devise a shoe insole to maximise the arch shape recovery and minimise the negative effects of the traditional design – restricted arch compression and recoil in gait.…”