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Ch07-I044963.fm Page 27 Tuesday, August 1, 2006 12:30 PM
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Tuesday, August 1,2006
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STUDY OF THE DESIGN METHOD OF
AN ANKLE-FOOT-ORTHOSIS

2
1
Yasuhiro Mine , Takamichi Takashima , Hiroshi Fujimoto J
1
National Vocational Rehabilitation Center
(The Graduate School of Human Sciences, Waseda University)
4-2 Namiki, Tokorozawa-City, Saitama, 359-0042 Japan
National Rehabilitation Center for Persons with Disabilities
4-2 Namiki, Tokorozawa-City, Saitama, 359-0042 Japan
3
The Faculty School of Human Sciences, Waseda University
2-579-15 Mikajima Tokorozawa-City, Saitama 359-1192 Japan

ABSTRACT
Ankle-Foot Orthoses (AFO) are orthotics for patients having pathological gait represented by the
stroke. In this study three-dimensional digital data from a physical object was extracted by using
3D-digitizer. If we have a 3D digitized orthotic model, the shape can be modified easily and Finite
Element Analysis (FEA) and Stereo-Lithography (Rapid-Prototyping System:RPS) can be easily
done. Continuing the research, we then focused on patients suffering from hemiplegics stroke in
order to develop a method of fabricating the AFO, which fit patients even more. The major purpose
of this study is to produce an orthotic design method for fitting each patient by measuring spastic
muscle action and by deducing parameters for an orthosis from the data. We will have to consider
how the outcomes of measurements should be processed as parameters in the design of 3DCAD.
KEYWORDS

Spasticity, Hemiplegic gait, Rehabilitation, Orthosis, 3Ddesign, Measurement
INTRODUCTION

Ankle-Foot Orthoses (AFO) are orthotics for the patients who have the pathological gait represented
by the stroke. They were using for the rehabilitation approach, and they support the pathological gait.
The conventional method of fabricating the plastic AFO as follows: a plaster cast of the leg is made,
then a thermoplastic resin is molded, with the basic form of the orthosis shaped by trimming, and
finally the fixtures are attached. The orthosis is adjusted by means of having the patient wear the
orthosis. In this study, three-dimensional digital data from a physical object was extracted using a
3D-digitizer. The process of digital scanning is made possible when some control lines are drawn on
the plaster model, and then the model is scanned along these control lines. If we have a 3D digitized
orthotic model, the shape can be modified easily and FEA and RPS can be easily done.