Joint adhesions, infection, osteonecrosis or bone marrow edema, breakage or retention of the built-in object, and problems associated with the healing process during arthroscopic access are some of the most common complications of knee arthroscopy. Articular adhesions of the knee are one of the major postoperative complications of arthroscopic knee ligament reconstruction surgery. Joint adhesions are defined as a reduction in the range of motion of the joint due to the formation of abnormal scarring within the joint after surgery. This includes both intra- and extra-articular pathological changes. Impaired joint motion can be complicated by persistent anterior knee pain, weakness, gait changes, and difficulty achieving preoperative motor function, resulting in patient dissatisfaction with the overall postoperative outcome. Patients with multiple ligamentous injuries are most likely to develop postoperative joint adhesions. Postoperative limitation of knee extension has a greater impact on knee function than limitation of knee flexion. When patients experience a 5°-10° limitation in knee extension, they experience abnormal gait, decreased quadriceps muscle strength, easy fatigue, and patellofemoral joint pain. Mild limitation of joint motion: knee extension limited by less than 5° and flexion maintained at >110°; Moderate limitation of joint motion: knee extension limited by 5°-10° and flexion limited by 90°-110°; Severe limitation of joint motion: knee extension limited by >10° and flexion limited by 90° or less; Severe limitation of joint motion: knee extension limited by >10° and flexion limited by 90° or less. and a flexion angle of 90° or less. Shelbourne et al. describe: Type 1: normal knee flexion with less than 10° extension limitation; Type 2: normal knee flexion with more than 10° extension limitation; Type 3: knee flexion limitation greater than 25° and extension limitation greater than 10°; Type 4: knee flexion limitation greater than 30° and extension limitation greater than 10° with patellar hypoplasia. Postoperative knee adhesions pathologically classified: 1. Limited anterior intra-articular adhesions: This lesion, also known as a nodular proliferative lesion, causes postoperative knee extension dysfunction due to the formation of anterior cruciate ligament nodules, which are mainly proliferating fibrous scar tissue. Intraoperative factors are the main cause of postoperative activity disorders. 2. Adhesions that extend from local disorders within the joint to the outside: This type of adhesion is also called infrapatellar contracture syndrome or patellofemoral entrapment syndrome. The abnormal proliferation of fibrous tissue in front of the patella leads to impaired flexion and extension of the joint, along with limited patellar movement and inferior patellar displacement. The subpatellar fat pad loses its normal mobility and flexibility and adheres to the proximal tibia, resulting in limited motion. Prolonged postoperative braking is a high-risk factor. 3. Total joint adhesions due to diffuse intra-articular and extra-articular disorders: extensive peri-articular fibrous scar formation due to excessive postoperative inflammatory response; extensive peri-articular fibrous scar formation accompanied by fibrosis of the joint capsule. How to prevent postoperative knee adhesions: 1. Preoperative: ① Surgery in the acute phase is a high risk factor for postoperative joint adhesions, so, at present, most physicians avoid ligament reconstruction in the acute phase and generally wait for the inflammatory response and swelling due to the injury to completely subside before performing surgery this phase takes 3-6 weeks. ② While waiting for the inflammatory response to subside after the injury, formal preoperative rehabilitation can be started. This includes quadriceps muscle strength exercises and restoration of joint mobility. Accelerate the recovery of postoperative function and improve surgical satisfaction. The goal of muscle strength recovery is to achieve more than 80% of the strength of the healthy leg, a normal gait and the ability to walk upstairs continuously. The goal of joint mobility recovery is to achieve more than 125° of full extension and flexion. 2. Intraoperative: Avoid excessive anteriority of the femoral or tibial tract, etc. 3. Postoperative: ① Wear a brace in extension or hyperextension immediately after surgery. ② Aggressive analgesia and elimination of swelling: non-steroidal anti-inflammatory drugs. Ankle pump, CPM treatment, etc. ③Strengthen postoperative rehabilitation exercises: improve joint mobility training, restore patellar motion trajectory, improve muscle strength training, balance, coordination and proprioceptive training, etc. Treatment of postoperative knee adhesions: For patients who still cannot achieve knee flexion of more than 90° and have more than 10° of extension limitation 4-8 weeks after surgery (time is not fixed, review the joint condition at any time), it is recommended to perform manual release and joint release by an experienced rehabilitation therapist. If necessary, arthroscopic release of adhesions should be performed. Arthroscopic release: Release: Physiological movements: flexion, extension, abduction, adduction, etc. Accessory movements: rotation, slip, rotation, sliding retraction, compression, traction, etc. Freehand manipulation: advancement: sudden high speed small movements. Freehand manipulation: smooth controlled pulling. Reported indications for knee adhesions include: knee flexion <125°, extension limitation >10°, and no significant improvement after 8 weeks of non-surgical treatment.