This study intends to perform round-tunnel and flat-tunnel ACL reconstruction technique in 144 patients, and compare the clinical outcomes of the two surgical procedures through follow-up.

This is a prospective randomized, controlled, multi-center clinical trial study on ACL reconstruction surgery technique. It is jointly undertaken by the Peking University Third Hospital, Nanjing Drum Tower Hospital, Zhengzhou Orthopaedic Hospital, and Shenzhen Second People's Hospital. Peking University Third Hospital is the team leader unit. In this study, 144 patients with ACL rupture were recruited according to the enrollment criteria. Among them, 54 patients with ACL rupture were recruited and carried out by the Peking University Third Hospital. The recruited patients were randomly divided into groups. The ratio of the control group is 1:1. Each of the other three hospitals recruited 30 patients and randomly grouped them according to the same enrollment criteria. The ratio of the experimental group to the control group was also 1:1. In this study, 72 patients with ACL rupture in the experimental group will be treated with flat-tunnel reconstruction technique, and 72 patients with ACL rupture in the control group will be treated with round-tunnel technique. All operations will be performed with autologous hamstring tendons. After reconstruction, all subjects will participate in the collection of clinical function scores including Tegner score, Lysholm score, IKDC score, and clinical evaluation including physical examination, joint laxity, CT and MRI imaging analysis to verify ACL Advantages of flat-tunnel technique.

Inclusion Criteria:

• For the first time, the knee joint simply ruptures the anterior cruciate ligament (ACL) and requires surgical reconstruction; it can be combined with meniscus injury, and the Outerbridge injury score is ≤ Grade II; There is no history of trauma or fracture of the ipsilateral knee joint; Posterior Cruciate Ligament (PCL) has no damage; Medial Collateral Ligament (MCL) or Lateral collateral ligaments (LCL) has no damage or only slight damage (no more than I degree).

Exclusion Criteria:

• BMI is less than 18.5 or greater than 35 kg/m2; Patients with moderate or severe knee degeneration; Those with limited flexion angle (<120 degrees); The cartilage defect area is greater than 2 cm2 or the Outerbridge damage score is> Grade II.