Femur fracture is most severe with fracture injury involving vascular nerves, femoral neck is most severe with post-fracture femoral head necrosis, and distal femur fracture is most severe with secondary knee deformity. Femur fracture includes proximal, diaphysis and distal fracture, among which femoral neck fracture, femoral diaphysis fracture and femoral condyle fracture cause the most serious secondary lesions. 1. Vascular and nerve injury: Femoral stem fracture, such as the middle and lower 1/3 fracture will cause blood vessel and nerve injury when it is severely displaced, resulting in lower limb sensory and motor disorders, as well as the arterial pulsation is weakened or disappeared. Severe cases can cause hemorrhagic shock. 2. Necrosis of femoral head: femoral neck fracture is a common type of proximal femoral fracture, and the most serious consequence is necrosis of femoral head caused by femoral neck fracture, which requires femoral head or total hip replacement in order to restore the joint function. 3. Joint deformity: for distal fractures, such as femoral condyle fracture involving the knee joint, mainly intra-articular fracture will be secondary to traumatic arthritis in the late stage, which can develop into knee deformity in the late stage. Therefore, femur fracture needs to clarify the degree of fracture as early as possible to avoid fracture affecting the late healing.