Article

The mechanisms altering knee flexion in hemiparetic gait may be
neurological (muscle overactivity) or orthopedic (soft tissue contracture) in
nature, a distinction which is difficult to ascertain clinically during gait.
This study aimed to distinguish the 2 mechanisms in evaluating thigh-shank
coordination, which may show instability across the gait cycle in the case of
bursting rectus femoris overactivity. METHODS: We measured thigh-shank
coordination in the sagittal plane using the continuous relative phase during
gait in 15 healthy subjects without and with an orthotic knee constraint (control
and constrained) and 14 subjects with hemiparesis and rectus femoris overactivity
before (pre) and after botulinum toxin injection. FINDINGS: Compared with the
control group, both orthopedic and neurological knee flexion limitations were
associated with decreased root-mean square of continuous relative phase over
swing (control, 72.9; constrained, 26.0, P<0.001; pre, 31.3, P<0.001). However,
only the neurological limitation was characterized by a higher number of
continuous relative phase reversals over swing (control, 2.3; pre, 4.0; P=0.001)
and late stance (control, 0.6; pre, 1.7; P<0.001). Botulinum toxin injection was
associated with a 40% increase in root-mean square of continuous relative phase
during swing and a 41% decrease in number of continuous relative phase reversals
during late stance, while peak knee flexion was increased by 31%. INTERPRETATION:
In hemiparesis, rectus femoris overactivity at swing phase is associated with
alternating thigh-shank coordination in swing and late stance, which improves
after botulinum toxin injection. Coordination analysis may help to distinguish
neurological from orthopedic factors in knee flexion impairment.
CI - Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS