Biomedical Engineering Reference
In-Depth Information
corresponds to premature wear of the cartilage protecting
the joint, which caused walking difficulties. Most studies on
modifications of gait in patients with gonarthrosis focus on
spatio-temporal parameters [DE 12, ORN 10], revealing that
these patients walked more slowly, with a reduced stride
length and a reduced simple stance phase compared to
control subjects. Some studies reported kinematic
modifications throughout the gait cycle in the sagittal plane,
mentioning a decrease in flexion amplitude and in the
maximal flexion of the knee in stance phase as well as an
increase in flexion of the knee upon heel strike [AST 08,
MUN 05, ZEN 09]. However, the changes of the kinematics
in the other planes, parameters that are more influenced by
measurement errors, are still very vague in the literature,
which was the reason behind this study.
This is a prospective study, carried out on 30 patients (18
females and 12 males, mean age 65.7 years old) presenting a
diagnosis of knee varus with arthrosis of the inner
compartment, with prosthetic surgery planned. The walking
distance of most of these patients was less than 1 km, and
the severity of their condition was classed from stage II to
stage IV of the Ahlbäck radiographic scale [AHL 68]. A group
of 12 control subjects with a varus morphotype, similar in
age, was also involved.
The experimental protocol initially familiarizes the
subject to walking on a treadmill; the comfortable walking
speed is established during this period. Then, the operator
attaches the hip, femur and tibia devices to the subject. The
position of the three points of support of the femur harness is
carefully adjusted, between the tendinous structures on
either side of the knee, to assure optimal monitoring of the
bone movement.
