Patient: At the end of February this year, when playing soccer, I accidentally pulled the ACL, and it took 20 days before I went to Beihang Hospital to take an MRI to confirm the diagnosis, and I was originally registered with a general number that said I needed surgery, but later, I registered with an old expert number, who said there was no need for surgery, and that there was no problem with conservative recovery, and told me how to recover. Now I am wearing a knee brace for two months, I can walk normally at night and day, I walk up and down stairs slowly, I insist on lifting my leg straight to contact my muscle strength, but my thigh muscles are growing very slowly, I have practiced a lot. Two days ago the review said stability is much better, knee bending 110 °. I can walk with a soft knee brace in two days, but not at night. Please, your opinion now, for my case. A: A torn ACL does not necessarily require surgery in its entirety. The key to surgery is to determine whether there are symptoms of instability: 1. whether the joint feels unstable and whether there is a sense of misalignment in the movement. 2. 2. Whether the joint can be accelerated or stopped in a straight line. 3.Whether you can jump on one leg (affected side) or not. 4.Can you perform a single-legged jump? 5.Can you perform sharp turning movements? In addition, many ACLs in the acute stage are intra-membranous ligament ruptures, which means that although the ligament is ruptured, the surrounding mucosa is fine.