[Biomechanics during cutting movement in individuals after anterior cruciate ligament reconstruction]

To evaluate knee biomechanics of patients about 12 months after anterior cruciate ligament (ACL) reconstruction during cutting and determine the abnormal biomechanical characteristics.

Sixteen males about 12 months after ACL reconstruction were recruited for this study. Three-dimensional kinematic and kinetic data were collected during cutting movement. Knee joint angles and moments were calculated. Paired t-tests were used to compare the differences in knee biomechanics between the surgical leg and nonsurgical leg.

The peak posterior ground reaction force (surgical leg: 0.380±0.071; nonsurgical leg: 0.427±0.069, P = 0.003) and vertical ground reaction force (surgical leg: 1.996±0.202, nonsurgical leg: 2.110±0.182, P = 0.001) were significantly smaller in the surgical leg than in the nonsurgical leg. When compared with the uninjured leg, the surgical leg demonstrated a smaller knee flexion angle (surgical leg: 38.3°± 7.4°; nonsurgical leg: 42.8°± 7.9°, P < 0.001) and larger external rotation angle (surgical leg: 10.3°± 2.4°; nonsurgical leg: 7.7°± 2.1°, P = 0.008). The surgical leg also demonstrated a smaller peak knee extension moment (surgical leg: 0.092 ± 0.031; nonsurgical leg: 0.133 ± 0.024, P < 0.001) and peak knee external rotation moment (surgical leg: 0.005 ± 0.004; nonsurgical leg: 0.008 ± 0.004, P = 0.015) when compared with the nonsurgical leg.

The individuals with ACL reconstruction mainly showed asymmetrical movements in the sagittal and horizontal planes. The surgical leg demonstrated a smaller peak knee flexion angle, knee extension moment, and knee external rotation moment, with greater knee external rotation angle.