ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

Applying Hernandez-Corvo procedure [7] it was determined that the metatarsus width
is 0.85 m. Meanwhile, the impression width in relation with the external arch is 0.45 m
and the relation percentage between these two values is 47 %, which allows to conclude
that it is a normal foot (since it is inside the 40 % to 54 % range). The tests were video
recorded during the step length (Figure 3), to later on use the video footage and define
the maximum parameters during the walking, as well as some other diverse information.
Tests were divided in two; on a flat surface (flat and rigid floor) and non-flat surface
(walking machine) (Figure 3). The foot was instrumented with three marks in specific
locations and data was taken during the walking cycle (Figure 3), later all these data will
be used to build the foot numerical model.
a) b)
Figure 3.- Walking tests. a) Flat surface. b) Non-flat surface.
Figure 4.- Foot location for instrumentation
Point 1 (Figure 4) is very important because it indicates the extreme part of the foot,
which is used to determine the magnitude of the dorsi-flexion and the instant the foot
leaves the floor. Point 2 (Figure 4) allows to locate and visualize the tibia position, as
well as of the fibula [8]. Finally, point 3 determines the metatarsus-phalangeal joint,
which is the traction transition for the final phase of the step [9]. The average obtained
results from 4 tests are presented in Table 1 (Figure 5), where position 1; illustrates the
beginning of the walking cycle, position 2; tibia at 90 o with respect to the floor, position
3; an instant before the heel looses contact with the floor and position 4; is the end of
the walking cycle. These illustrations are applied during the numerical analysis, and are
very use for due to the fact that they are the maximum angles that the patient reaches
during the walking cycle and the real foot work performs during the walking cycle.