Factors associated with stiff knee gait in patients with knee osteoarthritis.

Background: Stiff knee gait (SKG) is a common gait pattern in patients with knee osteoarthritis (KOA), characterized by reduced knee flexion excursion during gait. SKG can accelerate KOA progression; however, its underlying mechanisms and associated factors remain unclear. This study aimed to provide preliminary evidence on SKG-associated factors in patients with KOA. Methods: A pilot cross-sectional study was conducted at a single facility, including 21 patients with KOA undergoing rehabilitation. Knee flexion excursion during gait was assessed using a posture estimation library, classifying participants into SKG+ and SKG-. Evaluations covered pain intensity, muscle strength, knee range of motion (ROM), KOA severity, gait speed, fall efficacy, and health-related quality of life (QOL). Results were compared between groups to identify factors associated with SKG, and significant differences were analyzed for correlations with knee flexion excursion. Results: Among the 21 participants, 9 and 12 were in the SKG+ and SKG- groups, respectively. Significant differences were observed between the groups in pain intensity, quadriceps muscle strength, knee flexion ROM, and Western Ontario and McMaster Universities osteoarthritis index functional and total scores. Correlation analysis revealed that knee flexion excursion was moderately negatively correlated with pain intensity, moderately positively correlated with quadriceps muscle strength, and strongly positively correlated with knee flexion ROM. Conclusion: This study suggests that SKG in patients with KOA is associated with greater pain intensity, reduced quadriceps muscle strength, and decreased knee ROM. SKG may also negatively affect QOL. These preliminary findings indicate that targeted interventions addressing these factors could prevent and improve SKG.