Article

A linear piston hydraulic angular-velocity-based control knee joint was designed
for people with knee-extensor weakness to engage knee-flexion resistance when
knee-flexion angular velocity reaches a preset threshold, such as during a
stumble, but to otherwise allow free knee motion. During mechanical testing at
the lowest angular-velocity threshold, the device engaged within 2 degrees knee
flexion and resisted moment loads of over 150 Nm. The device completed 400,000
loading cycles without mechanical failure or wear that would affect function.
Gait patterns of nondisabled participants were similar to normal at walking
speeds that produced below-threshold knee angular velocities. Fast walking
speeds, employed purposely to attain the angular-velocity threshold and cause
knee-flexion resistance, reduced maximum knee flexion by approximately 25 degrees
but did not lead to unsafe gait patterns in foot ground clearance during swing.
In knee collapse tests, the device successfully engaged knee-flexion resistance
and stopped knee flexion with peak knee moments of up to 235.6 Nm. The outcomes
from this study support the potential for the linear piston hydraulic knee joint
in knee and knee-ankle-foot orthoses for people with lower-limb weakness.

Langue : ANGLAIS