To observe the knee joint kinematics after internal tension reducing technique assisted anterior cruciate ligament(ACL) single-bundle reconstruction under arthroscopy.

A study was performed on 80 patients with ACL injury from January 2017 to December 2018. Forty cases underwent ACL reconstruction assisted by intra articular graft tension reducing technique(experimental group) and 40 cases underwent the conventional ACL reconstruction(control group). The maximum step length, minimum step length, period of the limb walking and six freedom degrees of knee(flexion and extension angle, varus and valgus angle, internal and external rotation angle, antero-posterior displacement, proximal-distal displacement, internal and external displacement) at three, six, 12 months after operation were recorded by Opti_Knee(3D motion analysis system for the knee). The values of two groups were compared with 40 healthy adults. The count data were compared using the chi-square test, the paired t test was used for the pairwise comparison, the comparison among multiple groups was performed by Student-Newman-Keuls (SNK) analysis.

There was no significant difference in maximum step length, minimum step length, period of the limb walking between experimental group andcontrol group at three months, six months, and 12 months after the operation and healthy adults(P>0.05). The internal and external rotation angle(F=51.141, 13.204) and the antero-posterior displacement(F=51.246, 12.207) at three, six months after the operation of the experimental group were smaller than the control group(P<0.05), and were similar to the healthy adults(P>0.05). There was no significant difference in flexion and extension angle, varus or valgus angle, proximal-distal displacement, nor the internal or external displacement between the two groups(P>0.05). There was no significant difference in six freedom degrees of knee between the two groups at 12 months after the operation(P>0.05), which was similar to healthy adults(P>0.05).

Compared with conventional surgery, internal tension reducing technique assisted anterior cruciate ligament reconstruction could get more satisfactory early knee joint kinematics recovery, and the knee joint kinematics could more objectively evaluate knee function and stability.