People who are suitable for conservative treatment Patients over 60 years of age with significant degeneration of the joint surface. Children whose growth plates have not yet matured. Patients who are engaged in manual labor for a long time or who live in a sedentary position for a long time. Patients with partial injury and no symptoms of instability. Patients who are completely injured, but have no symptoms of instability or pain in daily life, and are willing to give up sports. The goal of conservative treatment is to restore most of the activities of daily living, without being able to meet the requirements of strenuous exercise. While previous conservative treatment included rest, ice, and brace braking, the new conservative treatment aims at rehabilitation. The rehabilitation process consists of two steps: the first step aims to eliminate the inflammatory response and restore joint mobility and muscle control. Ice is usually used to reduce pain and swelling, and joint mobility and patellar movement can be started immediately, along with muscle strength training to avoid muscle atrophy. The second step can be started once the patient returns to normal gait. The second step emphasizes N-cord and quadriceps strength training with open and closed chain exercises, ranging from high frequency and low intensity to low frequency and high intensity. Balance training and proprioceptive training are then performed. Following an ACL injury, approximately 90% of patients will experience meniscal wear or damage within 10 years of injury due to residual chronic instability of the knee, and over 70% will experience severe articular surface wear within 10 years of injury. With the anterior cruciate ligament intact, along with other intra- and extra-articular ligaments and muscles and the meniscus, the knee joint moves according to a set trajectory of regular motion. A joint that moves along a normal trajectory will not have its articular surfaces worn down. Once the ACL is ruptured, the trajectory of the knee joint changes, the joint surface becomes severely imbalanced, and the joint repeatedly misaligns, resulting in severe wear and tear of the articular cartilage and traumatic arthritis.