Artificial joint replacement is a true success achieved by modern medical science. Few techniques have brought such enormous benefits to patients and society as joint replacement. However, as with most other surgical procedures, the selection of the correct indications is crucial to obtaining a satisfactory surgical result. “The concepts of “indications” and “contraindications” actually represent the result of a complex decision-making process that must be completed by both the physician and the patient. The concepts of “indications” and “contraindications” actually represent the result of a complex decision-making process that must be shared between the physician and the patient. Any medical decision-making process requires careful consideration of the potential risks and benefits of a particular procedure, and this is especially true for surgical procedures. Both the patient and the surgeon must carefully evaluate the possible outcomes of surgical treatment, and in complex cases, the surgeon’s ability to communicate and educate the patient about the risks and benefits of a particular surgical procedure is even more important so that the patient can be an active participant in the decision-making process. The results of artificial joint replacement surgery are time-limited, making the elderly the best group to treat. The incidence of osteoarthritis in the elderly population is extremely high, severely affecting their ability to care for themselves and their quality of life. For elderly patients suffering from osteoarthritis with symptoms, as long as there is no serious systemic disease (such as severe coronary heart disease, untreated hypertension or diabetes mellitus, etc.), joint replacement surgery can be considered to alleviate the symptoms. Except for elderly patients, artificial joints should have a service life of 20-30 years after placement. Today’s artificial joints do not fully meet this requirement. With the prolongation of the implantation time, various complications can occur, and it is necessary to perform revision surgery again or even several times or leave serious disabilities. Therefore, the indications for artificial joint replacement should be strictly controlled. Especially in young patients, a cautious attitude should be taken. The basic reason is that it should be used in cases that are difficult to solve by other treatment methods (including surgery). Indications Artificial joint replacement is mainly used for joint diseases with pain and loss of function that are not treated by surgery or other kinds of surgical treatments are ineffective. Patients with limitation of movement without pain, unequal limb lengths, or severe joint lesions on X-ray but without obvious clinical symptoms are not indications for artificial joint replacement. 1, joint pain: difficult to control and obviously affect the function of joint pain, is the most important indication for artificial joint replacement. (1) Joint pain caused by local injuries and diseases: secondary osteoarthritis caused by various reasons is the most common in China, and the causes include trauma, dysplasia, joint surface unevenness caused by soft tissue lesions, joint alignment abnormality, poor limb alignment or joint instability. (2) Primary osteoarthritis: it is the first indication for artificial joint replacement in Europe and the United States. Domestic statistics are generally lower than secondary osteoarthritis, but it is still a common indication for hip and knee artificial joint replacement. (3) Systemic diseases: such as rheumatoid arthritis and lupus erythematosus. They are characterized by multiple joint damage, young patients and severe deformities. Surgery should be performed after the systemic disease is basically under control, and the surgical plan should be correctly arranged in conjunction with the patient’s condition. Inadequate scheduling can make the operation and postoperative care difficult. Surgery is difficult because patients often have severe soft tissue contractures and joint deformities. Except for mild contractures and deformities that can be corrected at the time of prosthesis replacement, severe soft tissue contractures and deformities should be corrected first, followed by artificial joint replacement. If it is expected to be solved in one stage by prosthesis replacement, it is often difficult to achieve the purpose, and will increase the incidence of intraoperative and postoperative complications. Tumor involving joints Prosthetic replacement of joints and adjacent bones is an important part of limb preservation therapy for bone tumors, which is often combined with chemotherapy or radiotherapy before and after operation. The tumor segment is widely resected during surgery, and then the bone and joint are reconstructed with artificial prosthesis. Customized prosthesis is often used to meet the needs of different cases. Infectious lesions used to be listed as contraindications for surgery. In recent years, there is an increasing trend in the report of using artificial joint replacement for cases where infection has been controlled, and for septic infections, some people have also had their lesions surgically removed under the protection of antibiotics, and the prosthesis replaced in one stage after adequate irrigation. In Europe, there are many successful cases of one-stage resurfacing for patients who have undergone revision surgery due to infection failure, but most authors still advocate surgery more than 1 year after complete infection control. In Asia, including the domestic has been in the bone and joint tuberculosis foci clearance at the same time, the one-phase artificial joint replacement, the near-term results are better, the long-term effect needs to be further observed. Contraindications 1, local or other parts of the active infection. Local skin, soft tissue and blood supply conditions are very poor, which may lead to difficulty in closing the incision or necrosis of soft tissue and skin in the incision area after surgery. 3.Neurogenic arthropathy. 4.Severe osteoporosis. 5, paralysis of muscles around the joints, which makes it difficult to keep the joints stable after surgery or to complete active joint movement. 6.Systemic conditions or concomitant diseases that make it difficult to tolerate replacement surgery. 7.Patients with a history of dementia and patients with unrealistic expectations.