For anterior cruciate ligament rupture of the knee, the best time for the patient to have surgery is about two weeks after surgery. The reasons for this are as follows: i. After knee injury, due to joint pain and swelling, the patient is emotionally tense and unable to complete the anterior drawer test and the Lachmann test, and can only make a preliminary judgment that a rupture of the ACL has occurred through joint swelling, restricted movement, and the imaging results shown by MRI of the knee. After two weeks, the swelling of the knee joint completely subsides and the muscle tension is relieved, at which point an accurate result can be obtained by physical examination. Second, after a knee injury with a large amount of intra-articular bleeding, it is necessary to wait until the blood accumulation in the joint is absorbed and the soft tissue swelling subsides before performing ACL reconstruction surgery, which can avoid bleeding from joint activities during the surgery to affect the surgical operation and also avoid joint stiffness after the surgery. It is recommended to make a rehabilitation training plan according to medical advice after surgery, and exercise step by step, you can do muscle contraction activities first, then to the movement of small joints, and gradually to the functional exercise of large joints, etc., from passive activities to active activities, specifically combining with the actual situation.