Effect of severity of knee osteoarthritis on the variability of gait parameters.

Gait analysis has provided important information concerning gait patterns and variability of gait in patients with knee osteoarthritis (OA) of varying severity. The objective of this study was to clarify how the variability of gait parameters is influenced by the severity of knee OA. Gait analysis was performed at three different controlled walking speeds in three groups of subjects with varying degrees of knee OA (20 healthy subjects with no OA and 90 patients with moderate or severe OA). The variability of gait parameters was characterized by the coefficient of variance (CV) of spatial-temporal parameters, as well as by the mean coefficient variance (MeanCV) of angular parameters. Based on our results, we conclude that the complexity of gait decreases if the walking speed differs from the self-selected speed. In patients with knee OA, the decreased variability of angular parameters on the affected side represents decreased joint flexibility. This leads to decreased consistency in movements of the lower limbs from stride-to-stride, as shown by increased variability of spatial-temporal parameters. Decreased joint flexibility and consistency of movement can be associated with decreased complexity of movement. Other joints of the kinetic chain, such as joints of the non-affected side and the pelvis, play an important role in compensation and adaptation of step-by step motion and in the ability of secure gait. Results suggest that the variability of gait associated with knee osteoarthritis is gender-dependent. During rehabilitation, particular attention must be paid to improving gait stability and proprioception and gender differences should be taken into account.