Once the hip joint is diseased, the cartilage of the joint surface will be severely worn and damaged, or even deformed and cause pain, which will lead to limitation of daily life activities. Common causes include osteoarthritis (degenerative arthritis), rheumatoid arthritis, ischemic necrosis of the femoral head, and fracture of the femoral neck. The damaged joint, the head of the femur, and the acetabular surface are surgically reconstructed and replaced with an artificial hip joint. After surgery, the following improvements can be achieved: (1) no more pain in the joint; (2) no need for long-term pain medication; (3) restoration of normal hip function; (4) release of psychological pain and depression.