Correlation of sit-to-walk and sit-to-stand performance with gait kinematic outcomes and self-reported pain and function in end-stage knee osteoarthritis

Sit-to-Walk (STW), 30-second Sit-to-Stand (30 s-STS), gait kinematic outcomes, and patient-reported outcome measures (PROMs) are used to assess pain and functionality in knee osteoarthritis (OA). However, their interrelationships in end-stage OA are unclear. This study investigates correlations between STW and 30 s-STS performance, gait kinematic outcomes, and PROMs in individuals with end-stage knee OA. Eleven participants (8 females, 3 males) with end-stage knee OA performed walking, STW, and 30 s-STS tests, recorded using a markerless motion capture system in a hospital. Visual3D analysis yielded 30 s-STS repetitions, STW time, knee flexion range of motion (ROM), stride width, and gait speed. Within two weeks, participants completed the EQ-5D-5L, Oxford Knee Score, and Numerical Pain Rating Scale. Pearson and Spearman rank orders were used to determine the correlations between these measures. A significant moderate positive correlation was observed between 30 s-STS and OKS: Function (ρ = 0.68, 95% CI 0.09 to 0.92, p = 0.03, R² = 0.46). No significant correlations were observed between STW or 30 s-STS performance and knee flexion ROM, gait speed, stride width, or the remaining PROMs. Preliminary findings indicate that more repetitions in the 30 s-STS is correlated with better perceived knee function in individuals with end-stage knee OA. This suggests that improvements in lower-limb strength and endurance may contribute to greater confidence in performing daily activities involving knee function. Further research with larger, more diverse cohorts is needed to clarify their role in preoperative assessment and rehabilitation planning.