Abstract: Objective  To investigate the characteristics of the three-dimensional gait changes of the knee joint after the single bundle anatomical reconstruction of autologous hamstring tendons after the rupture of the anterior cruciate ligament (ACL) of the knee. Methods  From August 2018 to June 2020，twenty five patients with ACL rupture of the lateral knee joint were selected as the injury group.During the operation,ACL rupture was confirmed by arthroscopy and the autologous hamstring tendon anatomical reconstruction was performed.Then 25 healthy people were selected as the control group.The three-dimensional gait data of normal knee joints were recorded with the three-dimensional motion capture system and compared with the injury group.In addition,the injury group was followed up before and after surgery and Lysholm knee joint function score was performed. Results  In the control group,the flexion and extension angle was - 2 °~66 °,the internal and external rotation angle was - 5 °~9 °,and the internal and external rotation angle was - 4 °~8 °.After ACL injury,the flexion and extension angle is - 5 °~52 °,the internal and external rotation angle is - 3 °~24 °,and the internal and external rotation angle is - 13 °~14 °.Three months after ACL autologous hamstring tendon reconstruction,the flexion and extension angle was - 2 °~47 °,the internal and external rotation angle was - 5 °~9 °,and the internal and external rotation angle was - 6 °~10 °.Six months after ACL reconstruction,the flexion and extension angle was - 2 °~59 °,the internal and external rotation angle was - 4 °~8 °,and the internal and external rotation angle was - 5 °~8 °.Nine months after ACL reconstruction,the flexion and extension angle was - 2 °~64 °,the internal and external rotation angle was - 2 °~9 °,and the internal and external rotation angle was - 2 °~8 °.12 months after ACL reconstruction,the flexion and extension angle was - 2 °~65 °,the internal and external rotation angle was - 1 °~9 °,and the internal and external rotation angle was - 1 °~8 °.After ACL rupture,the variation range of knee joint from flexion to extension,internal and external rotation,and internal and external turnover angle became larger than that of the control group,and there was significant difference in statistics(P<0.05).The angle range of each motion direction of knee joint after reconstruction was significantly improved compared with that before surgery（P＜0.05）,the difference at each time point after reconstruction was statistically significant compared with that before reconstruction(P<0.05).The gait at 9 and 12 months after reconstruction was significantly improved compared with that at 3 months after reconstruction (P<0.05).The Lysholm score increased from (62.35±3.45) before operation to (93.62±3.51) at 12 months after operation,and the difference was significant (P<0.05).  Conclusion  ACL reconstruction surgery has played a role in stabilizing the knee joint and improved the Lysholm knee joint function score,and with the passage of time after the operation,the Lysholm knee joint function score gradually improved,and basically returned to normal 9 months after the operation.

Key words: anterior cruciate ligament injury, ligament reconstruction, three-dimensional gait analysis