Rattling of the knee joint with movement may be caused by physiological reasons such as keeping the same position for a long time, or it may be caused by pathological reasons such as sports injury and chondromalacia patella. The treatments include general treatment, medication and surgery. 1. Physiological reasons: when keeping the same position for a long time, such as sedentary, standing for a long time, the lubricating fluid of the knee joint decreases, so when moving or bending and extending the knee joint, it will make a sound, which is a normal physiological phenomenon and does not need treatment. 2. Sports injury: When excessive sports may cause anterior and posterior cruciate ligaments or meniscus injuries in the knee joint, there may be a ringing sound in the knee joint during activities. Depending on the severity of the ligament or meniscus injury, you can choose rehabilitation exercise therapy or surgical suture repair. 3. Chondromalacia patella: Chondromalacia patella refers to the damage of patellar cartilage caused by the incorrect position of patella during knee activities, which may cause osteoarthritis of the knee and lead to the reduction of synovial fluid and rattling sound during activities. General treatment can be chosen through methods such as exercise rehabilitation or acupuncture, and analgesic drugs such as ibuprofen can also be taken appropriately. When the patient’s knee joint appears to stretch and bend with rattling symptoms, you also need to exclude whether there are meniscus injury and intra-articular free body and other diseases, you should consult a doctor in a timely manner, identify the cause of the disease and then choose the appropriate treatment for the different degrees of severity. Normally, we should increase outdoor activities and avoid prolonged bed rest.