Effect of walking speed and severity of hip osteoarthritis on gait variability.

Gait analysis in orthopaedic and neurological examinations is important; however, few studies assess gait variability at different walking speeds in patients with varying degrees of hip osteoarthritis. We aimed to clarify (1) how different controlled speeds and (2) various severities of hip osteoarthritis influence gait variability. Gait variability was described by the standard deviation (SD) of the spatial-temporal and mean standard deviation (MeanSD) of angular parameters. The spatial positions of the anatomical points for calculating gait parameters were determined in 20 healthy elderly controls and 20 patients with moderate and 20 patients with severe hip osteoarthritis with a zebris CMS-HS ultrasound-based motion analysis system at three walking speeds. The SD of the spatial-temporal and MeanSD of angular parameters of gait, which together describe gait variability, significantly depended on speed and osteoarthritis severity. The lowest variability in the gait was found near the self-selected walking speeds. Hip joint degeneration significantly worsened variability on the affected side, with non-affected joints and the pelvis compensating by increasing flexibility and adapting to step-by-step motions. Particular attention must be paid to improving gait stability and the reliability of limb movements in the presence of and increasing severity of osteoarthritis.