Article

OBJECTIVE: To test a new user-modulated control strategy that enables improved
control of a powered knee-ankle prosthesis during sit-to-stand and stand-to-sit
movements. DESIGN: Within-subject comparison study. SETTING: Gait laboratory.
PARTICIPANTS: Unilateral transfemoral amputees (N=7; 4 men, 3 women) capable of
community ambulation. INTERVENTIONS: Subjects performed 10 repetitions of
sit-to-stand and stand-to-sit with a powered knee-ankle prosthesis and with their
prescribed passive prosthesis in a randomized order. With the powered prosthesis,
knee and ankle power generation were controlled as a function of weight
transferred onto the prosthesis. MAIN OUTCOME MEASURES: Vertical ground reaction
force limb asymmetry and durations of movement were compared statistically
(Wilcoxon signed-rank test, alpha=.05). RESULTS: For sit-to-stand, peak vertical
ground reaction forces were significantly less asymmetric using the powered
prosthesis (mean, 19.3%+/-11.8%) than the prescribed prosthesis (57.9%+/-13.5%;
P=.018), where positive asymmetry values represented greater force through the
intact limb. For stand-to-sit, peak vertical ground reaction forces were also
significantly less asymmetric using the powered prosthesis (28.06%+/-11.6%) than
the prescribed prosthesis (48.2%+/-16%; P=.028). Duration of movement was not
significantly different between devices (sit-to-stand: P=.18; stand-to-sit:
P=.063). CONCLUSIONS: Allowing transfemoral amputees more control over the timing
and rate of knee and ankle power generation enabled users to stand up and sit
down with their weight distributed more equally between their lower limbs.
Increased weight bearing on the prosthetic limb may make such activities of daily
living easier for transfemoral amputees.
CI - Copyright (c) 2016 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS