Step-time variability is a specific gait characteristic associated with functional disabilities in knee osteoarthritis: The Nagahama study

Background

Gait characteristics of spatiotemporal parameters of knee osteoarthritis (OA) using large sample of patients with various radiographic severities and asymmetry have not been studied previously.

Objective

This study aimed to determine the disease-specific gait characteristics of knee OA and assess the spatiotemporal gait parameters associated with functional disability.

Method

The data was extracted from the Nagahama study and included 1591 participants aged ≥ 60 years, who underwent knee radiography and gait analysis. Of these, 998 (62.7 %) were assigned to healthy control group and 593 (37.3 %) to knee OA group. Gait speed, cadence, stride length, step length asymmetry, and step-time variability were measured using wearable inertial sensor. The Knee Scoring System (KSS) was used to assess functional disability. Logistic regression analysis was performed, with group variables as dependent variables and gait parameters as independent variables. In knee OA group, multiple regression analysis was performed with KSS score as dependent variable and gait parameters as independent variables after adjusting for potential confounders.

Results

Step-time variability was associated with knee OA (adjusted odds ratio [OR], 1.08; 95 % confidence interval [CI], 1.00–1.15; p = 0.037). Lower gait speed (Beta [B]=13.60; 95 %CI, 4.41–22.80; p = 0.004) and higher step-time variability (B=-0.82; 95 %CI, −1.40 to −0.24; p = 0.005) were associated with a decrease in KSS score in knee OA.

Conclusion

These findings suggest that higher step-time variability is a specific gait characteristic of knee OA and is a negative factor associated with functional disabilities. The assessment of step-time variability is a useful indicator for screening abnormal gait patterns in knee OA.