Article

A computer-controlled mechanism that fits a standard ankle-foot prosthesis was
designed to capture the absorbed energy in the ankle and delay its release until
specific times in the gait cycle. This mechanism used a direct current motor to
take up and hold the compression of a carbon-fiber ankle joint. Based on the
timing of the contact forces between the foot and the ground, a microprocessor
released the spring at preset times later in the gait cycle. This mechanism was
added to a Talux prosthetic foot and was employed by a user of a conventional
energy-storage ankle-foot prosthesis. His gait was recorded using a motion
analysis system. Five settings: 0, 55, 65, 75, and 85 ms delay were tested on
separate days, and the standard kinematic and kinetic gait data were recorded.
The user reported some settings were more comfortable than others. When these
preferences were tested with a randomized double-blind trial, the preferences
were not consistent. A second user showed a preference for the 55 ms delay. The
modifications to the device resulted in changes to the gait of the subjects,
including increased cadence and kinematics of the unaffected joints and a longer,
slower push from the ankle, which was noticed by both of the subjects.

Langue : ANGLAIS