Article

Knee osteoarthritis (OA) is a common disease that impairs walking ability and
function. We compared the temporal gait variability and motor control in people
with knee OA with healthy controls. The purpose was to test the hypothesis that
the temporal gait variability would reflect a more stereotypic pattern in people
with knee OA compared with healthy age-matched subjects. To assess the gait
variability the temporal structure of the ankle and knee joint kinematics was
quantified by the largest Lyapunov exponent and the stride time fluctuations were
quantified by sample entropy and detrended fluctuation analysis. The motor
control was assessed by the soleus (SO) Hoffmann (H)-reflex modulation and muscle
co-activation during walking. The results showed no statistically significant
mean group differences in any of the gait variability measures or muscle
co-activation levels. The SO H-reflex amplitude was significantly higher in the
knee OA group around heel strike when compared with the controls. The mean group
difference in the H-reflex in the initial part of the stance phase (control-knee
OA) was -6.6% Mmax (95% CI: -10.4 to -2.7, p=0.041). The present OA group
reported relatively small impact of their disease. These results suggest that the
OA group in general sustained a normal gait pattern with natural variability but
with suggestions of facilitated SO H-reflex in the swing to stance phase
transition. We speculate that the difference in SO H-reflex modulation reflects
that the OA group increased the excitability of the soleus stretch reflex as a
preparatory mechanism to avoid sudden collapse of the knee joint which is not
uncommon in knee OA.
CI - Copyright (c) 2015 Elsevier B.V. All rights reserved.

Langue : ANGLAIS