Take the most common artificial hip and knee joints in clinical practice as an example, there are mainly the following types: 1, according to the part of the joint being replaced, there are mainly total joint replacement (total hip, total knee) and hemi-joint replacement (unipolar femoral head, unicondylar replacement); 2, according to the way the joint is fixed after implantation, there are mainly bone cement type, non-bone cement type (biological pressure matching type) and mixed type; 3, according to the way the joint is matched There are metal-to-polyethylene, ceramic-to-ceramic, ceramic-to-polyethylene, metal-to-metal, etc. How to choose the right artificial joint for the specific case is very important for the surgical effect and later functional recovery, here are a few cases: 1, the total hip joint of elderly patients (over 70 years old with loose bone mass) is generally selected for mixed fixation, that is, the femoral side of the prosthesis is fixed with bone cement, and the acetabular side is fixed with non-cemented press-fit type. For young patients (with good bone quality under 60 years old), non-cemented biological fixation can be used for the total hip joint, and metal-to-high cross-linked polyethylene, ceramic-to-ceramic, or metal-to-metal joint can be used to reduce wear and tear if a greater amount of postoperative activity is required. large cases, a total knee joint with a tibial rotation platform and high flexion design can be used. For cases where one side of the knee joint is more damaged while the other side is basically intact, unicondylar knee replacement can be chosen; 4. For elderly people (over 70-75 years old) with femoral neck fracture, who do not require high mobility, or who have partial internal organ dysfunction but can still tolerate surgery, unipolar or bipolar artificial femoral head hemi hip replacement can be chosen. The advantages are shorter operation time, less trauma, less intraoperative bleeding, less postoperative complications, faster recovery and safer throughout the perioperative period. In conclusion, the correct and appropriate selection of the artificial joint is a very important and even decisive part of the entire surgical treatment process.