Psychometric properties of shoulder-pelvis coordination in hip osteoarthritis patients

Abstract

Introduction Coordination between shoulder and pelvis girdles during walking is pivotal to optimise a stable forward displacement (Lamoth and van Heuvelen, 2012). Hip osteoarthritis (HOA) increases the stiffness of the pelvis and the low back and should impair this coordination. To our knowledge, no study evaluates this outcome for HOA. The aim was to evaluate the psychometric properties of the pelvis-shoulder coordination in healthy (HEA) and non-severe unilateral HOA subjects. Material and methods 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). Results 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%, P r > 0.24, P r = −0.27, P = 0.013 for Lesquene index). Discussion–conclusion 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.