With the continuous improvement of people’s life, China has entered into an elderly society. And geriatric diseases, including osteoarthrosis of the knee, osteoarthrosis of the hip, femoral neck fracture and aseptic necrosis of the femoral head due to trauma and non-trauma, are increasing. According to statistics, 50% of people over 50 years of age suffer from osteoarthrosis, and 90% of women and 80% of men over 65 years of age suffer from this disease. These diseases seriously affect the quality of life of the elderly and even pose a threat to their lives; elderly patients not only suffer from the pain of the disease, but also bring many burdens to their families and society. Nearly 30 years of experience has proven that for severely diseased joints, artificial joint replacement has the combined advantages of relieving joint pain, maintaining joint mobility, maintaining joint stability and not affecting or repairing limb length. Total hip replacement and total knee replacement is one of the most effective ways to treat age-related osteoarthrosis, improve the quality of life of the elderly and extend their life expectancy. Total Knee Arthroplasty (TKA): This is a total knee arthroplasty in which the diseased femoral, tibial and patellofemoral surfaces are removed and replaced with a metal surface, separated by a polymer polyethylene pad. The metal materials used are t-molybdenum and titanium alloys, which are histocompatible with human tissue and have no rejection; at the same time, the design of the modern artificial knee joint is more in line with the requirements of human biomechanics. Total knee replacement is mainly used for osteoarthritis and rheumatoid arthritis of the knee joint. The purpose of total knee replacement is firstly to solve the patient’s pain problem; secondly to provide stable joint motion; and finally to correct the deformity. With a successful knee replacement, the patient’s painful symptoms disappear and he or she is able to restore his or her normal walking and stair function and appropriate physical activity. Total Hip Arthroplasty (THA): The human hip joint is composed of the femoral head, the acetabulum and the surrounding soft tissues. Total hip arthroplasty is the replacement of the human femoral head and acetabulum with artificial materials. The metal materials used are mainly titanium alloy and polymer polyethylene. It also has good histocompatibility and meets the requirements of human biomechanics. It is mainly used for osteoarthritis of the hip joint, femoral head necrosis, femoral neck fracture and congenital hip dislocation. The purpose of total hip arthroplasty is mainly to solve the patient’s pain problem; secondly, to provide stable joint movement; and finally, to provide bilateral lower extremity equilibrium.