Effect of anterior cruciate ligament rupture on hamstring∶quadriceps ratio during isokinetic knee extension and flexion at 30 degrees of flexion / 北京大学学报(医学版)

ABSTRACT

Objective:To evaluate the change in hamstring ( H )quadriceps ( Q ) ratio following anterior cruciate ligament ( ACL) rupture during isokinetic knee extension and flexion at 30 degrees of flexion which is important for knee dynamic function .Methods:A study was performed in 25 male com-plete unilateral ACL ruptures .Isokinetic concentric and eccentric quadriceps and hamstring muscle tests in both the deficient knees and intact knees were performed at 60°/s, respectively.At 30 degrees of flexion, the average torque of quadriceps and hamstring , Qe∶Qc ratios ( ratios of eccentric quadriceps to concentric quadriceps muscle torque ) , He∶Hc ratios ( eccentric hamstring to concentric hamstring ) , Hc∶Qc ratios ( concentric hamstring to concentric quadriceps ) , He∶Qc ratios ( eccentric hamstring to con-centric quadriceps ) , and Hc∶Qe ratios ( concentric hamstring to eccentric quadriceps ) were calculated . Wilcoxon matched-pairs signed-ranks test was used .Results:At 30 degrees of knee flexion , a significant reduction ( P<0.05) in the average torque of quadriceps was observed at concentric and eccentric 60°/s produced by the deficient-side compared with the intact side .In addition, Hc∶Qc, He∶Qc, and Qe∶Qc significantly increased on the ACL-deficient side .Conclusion:The change in H ∶Q ratio in the mode of isokinetic 60 °/s at 30 degrees of knee flexion might therefore be a new tool to objectively document muscle function in ACL-deficient knee .