Stage-specific gait deviations in individuals with hip osteoarthritis.

Objective: This cross-sectional study examined stage-specific biomechanical differences in individuals with hip osteoarthritis (OA) compared to healthy controls, aiming to identify markers of disease severity and progression.

Methods: Thirty participants were categorised into three groups: healthy controls, radiographic early-to-moderate hip OA, and radiographic moderate-to-severe hip OA. Spatiotemporal, kinematic, and kinetic parameters were extracted and a one-way ANOVA was used to detect group differences. Spearman's rho correlations evaluated associations between key biomechanical parameters and the Hip Disability and Osteoarthritis Outcome Score (HOOS).

Results: Participants with moderate-to-severe hip OA exhibited significantly lower gait speed (p < 0.001, Cohen's d = 2.08), cadence (p = 0.037, Cohen's d = 1.31), step length (p < 0.001, Cohen's d = 1.90), stride length (p < 0.001, Cohen's d = 1.99), early stance hip adduction moment (HAM) (p < 0.001, Cohen's d = 3.13), hip flexion moment (p < 0.001, Cohen's d = 3.42), hip extension moment (p = 0.016, Cohen's d = 1.35), and knee flexion moment (p = 0.012, Cohen's d = 1.52), alongside increased step width (p = 0.008, Cohen's d = -1.42), compared to healthy controls. Early-to-moderate hip OA participants also demonstrated significantly lower gait speed (p = 0.008, Cohen's d = 1.89), step length (p = 0.014, Cohen's d = 1.56), stride length (p = 0.008, Cohen's d = 1.72), early stance HAM (p = 0.044, Cohen's d = 1.09), and hip flexion moment (p < 0.001., Cohen's d = 2.93) relative to controls. Early stance HAM further distinguished between early and advanced stages of the disease (p = 0.016, Cohen's d = 1.25) and was positively correlated with HOOS (r = 0.604, p < 0.001).

Conclusions: Distinct HAM differences in early stance of gait differentiate hip OA stages. Monitoring this potential biomechanical marker may enable early detection and targeted interventions to optimise gait mechanics and improve outcomes in individuals with hip OA.