Article

Five solid-ankle experimental prosthetic feet were used in this double-blind
randomized crossover study to determine the effects of forefoot flexibility on
gait of 14 unilateral transtibial prosthesis users.
Flexibility in experimental
feet was altered by changing the number of flexural hinges in their forefoot
sections. When experimental prosthetic foot conditions were compared, measured
prosthetic ankle dorsiflexion range of motion increased as much as 3.3 degrees
with increasing flexibility (p < 0.001) and the foot's anterior moment arm
(measured as the effective foot length ratio) increased as much as 23% of the
foot length with decreasing flexibility (p < 0.001). Subjects also showed
increases in the difference between sound and prosthetic ankle moments as high as
0.53 Nm/kg in late stance phase of walking as flexibility decreased (p < 0.001).
The difference between first peaks of the vertical ground reaction forces on the
sound and prosthetic sides increased as much as 9% of body weight when subjects
used the foot with the greatest flexibility (p = 0.001).
The results of this
study suggest solid-ankle prosthetic foot designs with overly flexible forefoot
sections can cause a "drop-off" effect in late stance phase and during the
transition of loading between prosthetic and contralateral limbs.

Langue : ANGLAIS