Abstract: BACKGROUND: Previous studies have shown that knee joint moment changes in patients with knee osteoarthritis, but there are few reports on the correlation of moment changes with knee extensor muscle strength and gait spatiotemporal parameters.
OBJECTIVE: To explore the correlation of knee extensor muscle strength and gait spatiotemporal parameters with peak knee flexion moment and knee adduction moment in female patients with knee osteoarthritis. 
METHODS: Twenty knee osteoarthritis female patients with single knee disease hospitalized in Guizhou Hospital, Beijing Jishuitan Hospital from February to August 2022 were selected as the knee osteoarthritis group, and an additional 20 healthy females without musculoskeletal disease were selected as the control group. The knee extensor force at 60 (°)/s was measured with the Biodex isokinetic instrument. The gait spatiotemporal parameters and peak knee flexion moment and knee adduction moment were collected with the Italian BTS infrared motion capture system and force measuring platform. Pearson correlation analysis was used to explore the correlation of muscle strength and gait spatiotemporal parameters with peak knee adduction moment and knee flexion moment, and the variables significantly related to knee joint moment were further included in the multiple stepwise regression analysis. 
RESULTS AND CONCLUSION: (1) Compared with the control group, the knee osteoarthritis group had significantly lower knee extensor force, step speed, step frequency, step length, step width, peak knee adduction moment and knee flexion moment at 60 (°)/s (P < 0.05). (2) Pearson correlation analysis showed that the 60 (°)/s centripetal extensor force, step speed, step frequency and step length were positively correlated with the peak knee flexion moment, and negatively correlated with the peak knee adduction moment, with a statistically significant difference (P < 0.05). (3) The results of multiple stepwise regression showed that step speed and 60 (°)/s knee extensor force were the strongest predictors of peak knee flexion moment, and the total R2 value of the two factors was 0.426, indicating that 42.6% of the total variance of this parameter could be explained. Step length and 60 (°)/s centripetal extensor force were the strongest predictors of peak knee adduction moment. The total R2 value of the two factors was 0.602, indicating that 60.2% of the total variance of this parameter could be explained. (4) It is concluded that knee extensor strength, step speed and step length are the main variables affecting peak knee adduction moment and knee flexion moment. Therefore, these variables can be used for clinical gait monitoring and guidance to change knee joint load during knee osteoarthritis rehabilitation. 

Key words: knee osteoarthritis, muscle strength, spatiotemporal parameter, knee joint moment, gait