Hip joint motion and gluteal muscle activation differences between healthy controls and those with varying degrees of hip osteoarthritis during walking

Purpose: Compare gluteal muscle activation patterns and three-dimensional hip joint movements among those with severe hip osteoarthritis (OA), moderate OA and a healthy group during walking. Scope: 20 individuals with severe OA, 20 with moderate OA and 20 healthy individuals were recruited. Three-dimensional hip motion and surface electromyograms from gluteus maximus and medius were collected during treadmill walking at a self-selected speed. Angular displacement characteristics were calculated for three-dimensional hip motions. Principal component analysis extracted amplitude and temporal features from electromyographic waveforms. Analysis of Variance models and student t-tests using Bonferroni corrections determined between group differences in these gait features (α= 0.05). Conclusions: Sagittal plane hip range of motion was significantly reduced with increasing severity of OA (p< 0.05) where as frontal and transverse plane range of motion was reduced in the severe OA group only (p< 0.05). Activation patterns of gluteus medius and maximus did not differ between the healthy group and those with moderate hip OA (p> 0.05). Individuals with severe OA walking with more prolonged gluteus maximus activation and prolonged and less dynamic gluteus medius activation compared to the other two groups (p< 0.05). This study highlights the changing function of the hip joint during walking with increasing hip OA severity.