HEA and HOA subjects were enrolled. Each participant performed a 3D gait analysis along a 6-metre walkway using an optoelectronic system with 8 cameras (100 Hz). HOA performed a second session to evaluate measurement's reliability (test-retest). Pelvis and shoulder yaws (transverse plane) and rolls (frontal plane) were calculated using markers positioned on the acromial process and the anterior-superior iliac spines. The phase-lag between angle waveforms expressed as a gait cycle's percentage was computed using continuous estimate of relative phase (CRP; Russell Esposito and Wilken, 2014). Intraclass correlation (ICC), one-way Anova and Pearson correlation coefficient were used to evaluate respectively, reliability, responsiveness and validity (against HOOS scores; Ornetti et al., 2009).
Seventy-eight HEA (58.4 ± 15.4 years) and 103 HOA (61.0 ± 8.1 years) subjects were included. ICC were excellent for roll-lag (0.918) and yaw-lag (0.959). Significant difference was found for roll-lag between subjects (HEA 37.8 ± 10.6%; OA 29.5 ± 9.8%,
Pelvis-shoulder coordination outcomes showed excellent reliability. Roll-lag was related to clinical scores whereas yaw-lag did not. As only non-severe patients were included, these outcomes need to be addressed in population with higher impairment. It could be then proposed as an objective outcome to evaluate deficit in hip osteoarthritis patients.