Document Type



Objective: To study the correlation between muscle strength asymmetry and gait asymmetry in 1 year after (Anterior Cruciate Ligament Reconstruction, ACLR).

Methods: Twenty-five ACLR patients were enrolled in the Department of Sports Medicine, Peking University Third Hospital. Data of isokinetic muscle strength test one year after ACLR were collected. The concentric and eccentric strength of extensor and flexor muscles at 60°/s, 180°/s and 300°/s on the uninjured side and the injured side were measured respectively, and the peak value of muscle strength was analyzed. The three dimensional motion information and ground reaction force during gait were collected, and the peaks of three dimensional joint angle and moments during gait stance phase were calculated by inverse dynamics analysis. The paired-samples T test was used to analyze the difference of gait parameters and isokinetic muscle strength peaks. Spearman correlation analysis was used to study the correlation between bilateral asymmetry index of isokinetic muscle strength and gait asymmetry index. Results: One year after ACLR, the isokinetic muscle strength peaks of the flexor and extensor muscles on the injured side were significantly lower than those on the uninjured side【60°/s extensor concentric, the injured side: (1.22 ± 0.4)Nm·kg-1, uninjured side: (1.73 ± 0.42)Nm·kg-1, bilateral difference: (-0.5 ± 0.39)Nm·kg-1, P < 0.01; 60°/s flexor concentric, injured side: (0.84 ± 0.19)Nm·kg-1, uninjured side: (1.05 ± 0.23)Nm·kg-1, bilateral difference: (-0.21 ± 0.14)Nm·kg-1, P < 0.01】. Compared with the uninjured side, the injured side showed insufficient knee extension at the time of maximum knee extension during stance phase 【injured side: (5.25 ± 4.17) °, uninjured side: (2.24 ± 3.11) °, bilateral difference: (3.01 ± 2.44) °, P < 0.01】, and the peak extension moment decreased significantly 【injured side: (0.1 ± 0.09) Nm·kg-1·m-1, (0.15 ± 0.07) Nm·kg-1·m-1, (-0.05 ± 0.06) Nm·kg-1·m-1, P < 0.01】. One year after ACLR, the asymmetry of 180°/s isokinetic extensor concentric strength was significantly correlated with the asymmetry of peak flexion moment (R = 0.449, P = 0.024). The asymmetry of 60°/s isokinetic extensor concentric strength was significantly correlated with the asymmetry of peak internal rotation moment (R = 0.421, P = 0.036). One year after ACLR, asymmetries of 180°/s, 300°/s isokinetic extensor concentric strength and 60°/s isokinetic flexor eccentric strength were significantly correlated with peak asymmetries during stance phase. Conclusion: There is a significant correlation between isokinetic muscle strength asymmetry of knee and gait asymmetry. This study suggests that ACLR patients still need regular rehabilitation training to improve muscle strength and motor function 1 year after ACLR, so as to reduce the risk of reinjury and secondary injury.

New Investigator Award