The length of the femur varies from person to person and is about 1/4 of one’s height. The femur is the longest and strongest long bone in the body and can be divided into the femoral body and the two ends of the femur. The upper end has the femoral head facing inward and upward, and the thinner part of the femoral head slightly below is called the femoral neck, while the area where the femoral neck joins the femoral body is called the femoral intertrochanter. The femoral neck and femoral intertrochanter are prone to fracture in elderly patients. The distal femur has a medial and lateral condyle, which form the knee joint with the tibial plateau, respectively. The femoral trochlea is formed in front between the medial and lateral condyles, and the articular surface of the patella forms the patellofemoral joint, which is prone to local injury when going up and down stairs, forming patellofemoral joint degeneration and leading to patellofemoral arthritis, and patients may have symptoms such as pain and restricted activity. The femoral stem is prone to fracture under violent violence, causing displacement, and usually requires surgical incision and internal fixation treatment to recover.