Gait variability and motor control in people with knee osteoarthritis.
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.
Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark. Electronic address: talkjaer@sund.ku.dk.
Tine
T
Alkjaer
Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
Peter C
PC
Raffalt
Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
Helle
H
Dalsgaard
Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark.
Erik B
EB
Simonsen
Department of Neuroscience and Pharmacology, University of Copenhagen, Denmark; Department of Nutrition and Exercise, University of Copenhagen, Denmark.
Nicolas C
NC
Petersen
Clinical Motor Function Laboratory, The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals Bispebjerg and Frederiksberg, Nordre Fasanvej 57, 2000 Frederiksberg, Denmark.
Henning
H
Bliddal
Clinical Motor Function Laboratory, The Parker Institute, Department of Rheumatology, Copenhagen University Hospitals Bispebjerg and Frederiksberg, Nordre Fasanvej 57, 2000 Frederiksberg, Denmark.
Marius
M
Henriksen
D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology*; D006181:H-Reflex / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D012026:Reflex, Stretch / Q000502:physiology; D016138:Walking / Q000502:physiology
Gait variability; H-reflex; Knee OA; Motor control; Walking