Article

The asymmetry in step length in prosthetic gait is often seen as a
detrimental effect of the impairment; however, this asymmetry also might be a
functional compensation. An advantage of a smaller step length of the
nonprosthetic leg, and specifically foot forward placement (FFP), might be that
it will bring the center of mass closer to the base of support of the leading
foot and thus increase the backward margin of stability (BW MoS). OBJECTIVE: The
purpose of this study was to characterize differences in step length, FFP, and
the concomitant difference in BW MoS between steps of the prosthetic and
nonprosthetic legs (referred to as prosthetic and nonprosthetic steps,
respectively) of people after transtibial amputation. DESIGN: This was an
observational and cross-sectional study. METHODS: Ten people after transtibial
amputation walked for 4 minutes on a self-paced treadmill. Step length and FFP
were calculated at initial contact. The size of the BW MoS was calculated for the
moment of initial contact and at the end of the double-support phase of gait.
RESULTS: Step length (5.4%) and FFP (7.9%) were shorter for the nonprosthetic
step than for the prosthetic step. The BW MoS at initial contact was larger for
the nonprosthetic step, but because of a significant leg x gait event interaction
effect, BW MoS did not differ significantly at the end of the double-support
phase. LIMITATIONS: All participants were relatively good walkers (score of E on
the Special Interest Group in Amputee Medicine [SIGAM] scale). CONCLUSIONS: The
smaller step length and FFP of the nonprosthetic step help to create a larger BW
MoS at initial contact for the nonprosthetic step compared with the prosthetic
step. Hence, step length asymmetry in people after transtibial amputation might
be seen as a functional compensation to preserve BW MoS during the double-support
phase to cope with the limited push-off power of the prosthetic ankle.
CI - (c) 2014 American Physical Therapy Association.

Langue : ANGLAIS