Article

Prosthetic devices are intended to return lower limb amputees to
their pre-amputation functional status. However, prosthetic devices designed for
unilateral below-knee amputees have yet to completely restore the biomechanical
functions normally provided by the ankle muscles, leading to gait asymmetries and
increased reliance on their intact leg. In an effort to improve amputee gait,
energy storage and return feet have been developed that store mechanical energy
in elastic structures in early to mid-stance and return it in late stance.
However, little is known regarding how ankle compliance and the level of energy
return influences walking mechanics. The purpose of this study was to identify
the influence of prosthetic ankle dorsiflexion and energy storage and return on
leg loading during steady-state walking. METHODS: Compliant ankles with different
stiffness levels were attached to a Seattle Lightfoot2 in different orientations
(forward- and reverse-facing). FINDINGS: The ankles decreased residual leg
vertical ground reaction forces in late stance, increased residual leg propulsive
ground reaction force impulses and increased residual leg knee joint extensor
moments. The reverse-facing ankles increased residual leg vertical ground
reaction forces in early stance, and the compliant forward-facing ankle increased
residual leg braking impulses. In contrast to previous studies, increased energy
storage and return from compliant ankles did not decrease hip joint powers or the
intact leg vertical ground reaction forces. INTERPRETATION: These results provide
insight into the relationships between ankle dorsiflexion, energy storage and
return, and leg loading, which may lead to more effective prosthetic devices to
improve amputee gait.
CI - Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS