Eight years after total knee arthroplasty, there is soreness in sleeping at night. It is necessary to clarify the causes of the disease, such as high activity level, prosthesis obstacle, primary disease of the knee joint, cold and other factors, and give general treatment, physiotherapy, medication, physical therapy and so on for the causes of the disease. 1. High activity level: This is the most common cause of postoperative pain, which requires moderate exercise to reduce the weight of the knee joint, which helps to avoid pain and prolongs the life of the prosthesis. 2. Prosthesis obstacle: because the prosthesis also has a service life, if the operation time is too long, or the patient’s own osteoporosis and other factors can lead to prosthesis sinking, loosening, pain on the affected side, generally for the evaluation of patients with prosthesis obstacle, need to consider the revision surgery. Patients with osteoporosis tendency can be given anti-osteoporosis treatment, such as calcium gluconate, salmon calcitonin and other drugs. 3. Knee primary disease: most of them are synovitis and other diseases, this kind of patients pay attention to reduce the knee joint weight bearing and activities, with non-steroidal drug treatment, such as ibuprofen, celecoxib and other drugs. 4. Cold factors: patients do not pay attention to maintenance, due to cold and other factors can also cause pain, pay attention to the knee joint warmth, can give targeted hot compresses. If the time after knee replacement is too long, you need to consult the hospital in time, review the X-ray in time, and pay attention to the maintenance.