Artificial joint replacement: People do not know much about artificial joints, and often think that during surgery, the joint will be completely removed and fitted with a stainless steel joint, and that after surgery the limb will be like a robot, stiff and unnatural. In fact, artificial joint replacement only removes the worn and damaged joint surface and implants it like a dental brace to restore a normal smooth joint surface. Artificial joint replacement is one of the greatest breakthroughs in the field of orthopedics in decades. It is now being used to treat the shoulder, elbow. Wrist, interphalangeal, hip, knee, and ankle joints are among the most commonly used, with hip and knee replacements being the most common. The design and material of artificial joint prosthesis is the result of continuous efforts of biomechanics experts, material engineers and orthopedic surgeons. It is mostly made of metal and high-density plastic materials, according to the structure, shape and function of the human joint. The types of metal, including alloys, high-density wear-resistant polyethylene, etc., have improved the success rate and service life of artificial joint replacement in recent years. The artificial joint and the bone can be fixed by bone cement or by using the special structure of the artificial joint surface to allow the bone to grow in to achieve stability. Diseases requiring artificial joint replacement include joint pain and dysfunction due to osteoarthritis; severe rheumatoid arthritis, aseptic necrosis of the femoral head, traumatic arthritis, certain hip fractures, benign and malignant tumors, and ankylosing crepitus. Patients who opt for surgical treatment must be aware of the following: preparation of x-rays of the joint; presence of moderate to severe persistent pain; and lack of substantial improvement with long-term conservative treatment. Conservative treatment includes: pain relievers or NSAIDs, physical therapy, walkers (crutches), and conscious reduction of physical activity that may cause discomfort. The optimal age for surgery was previously considered to be between 60 and 75 years of age for prosthetic joint replacement. However, with improvements in the design and materials of artificial joints and surgical techniques, age is no longer an absolute contraindication to surgery, and many older patients, as well as many younger patients, have successfully undergone arthroplasty. The longevity and efficacy of the artificial joint is a major concern for patients. The greatest benefit of artificial joint surgery is the elimination of joint pain, the significant improvement in joint function, and the improvement in the patient’s quality of life so that he or she can work and live well during their lifetime. Currently, more and more patients understand and are happy to undergo artificial joint replacement surgery. The longevity of artificial joints is determined by two main issues: the wear and tear of the joint and the loosening of the prosthesis caused by wear particles. In developed countries, more than 90% of the artificial joints that were surgically inserted twenty years ago are still intact and can continue to be used. Complications of joint replacement: 1. The incidence of infection after artificial joint replacement is decreasing year by year, but it is the most important concern for doctors and patients. 2, artificial joint dislocation occasionally occurs after artificial hip replacement, the incidence is less than 3%, if the prosthesis installation position is satisfactory, functional exercise, basically can avoid the occurrence. Most of them can be reset by manipulation. 3, artificial joint wear, with the improvement of artificial joint design and material, the incidence of wear and tear of the prosthesis has been increasingly reduced. 4. Other conditions, such as vascular and nerve damage, fractures, venous embolism, joint instability, etc., are rare, especially in hospitals with high surgical volumes. Osteoarthritis of the knee, also known as degenerative arthritis of the knee, senile arthritis, hypertrophic arthritis or osteophytes (bone spurs), is a frequent and common disease in the elderly population. The etiology of osteoarthritis of the knee can be attributed to age-related degenerative changes in the knee cartilage, and from this point on the course of the disease is irreversible. Patients with early onset of the disease may have knee discomfort from their forties onwards, typically in the form of pain, especially when walking up and down stairs. At this time, there are no abnormalities on x-rays and no obvious positive signs on physical examination, which is considered early mild osteoarthritis. In moderate osteoarthritis, the pain and other discomfort symptoms are aggravated, and there may be mild bone redundancy on X-rays and narrowing of the joint space (especially in the patellofemoral joint), and on physical examination there is mainly a subtle rubbing sensation on the patellofemoral joint surface, and sometimes a mass (N-fossa cyst) can be felt from the back of the knee. In severe cases, the pain is obvious and walking is limited, even if not relieved by painkillers. In acute attacks, there may be swelling and fluid accumulation in the knee joint, and more joint fluid may be extracted from the joint cavity. Treatment of osteoarthritis of the knee varies according to its severity. Generally speaking, mild cases are treated with maintenance, supplemented by appropriate medication. For moderate patients, in addition to the above measures, sodium hyaluronate can be injected into the knee joint, usually once a week for five weeks, with satisfactory results in most patients; for severe patients, if there is fluid in the joint, hormonal drugs can be injected into the joint after puncture and fluid extraction to inhibit inflammatory response. However, in general, conservative treatment is often ineffective and the patient has difficulty in obtaining sustained pain relief, which in turn affects the function of the knee and daily life, and it is time to solve the problem surgically. There are a variety of surgical options, but if the degeneration of the knee joint is really severe, the only option is to have a knee arthroplasty. Total knee arthroplasty is an effective treatment for severe knee osteoarthritis, which is performed by reconstructing the knee joint to relieve pain and improve function. During the surgery, the surgeon removes all the worn cartilage surfaces of the upper and lower knee joints, i.e., the femur and tibia, and then installs metal femoral and tibial prostheses to restore normal physiological function of the knee joint by reconstructing the alignment of the knee joint, correcting the line of force of internal and external rotation, and re-establishing soft tissue balance. Currently, total knee replacement surgery is widely performed in large hospitals in China and is technically very mature, with satisfactory postoperative follow-up results.