The difference between sciatica and necrosis of the femoral head is mainly due to different causes, different pain locations and different treatment methods. 1. Different causes: Necrosis of femoral head is usually caused by poor healing of femoral neck fracture or long-term use of hormones, and sciatica is usually caused by lumbar intervertebral disc herniation and compression of nerves. 2. Different pain location: the pain of femoral head necrosis is in the hip joint, proximal thigh, radiating to the knee, limiting hip activities, especially rotational activities. Sciatica pain is mainly in the lumbosacral region, the buttocks, the back of the thighs, calves and other parts of the pain may also be painful, or accompanied by numbness. 3. Different treatment methods: femoral head necrosis should gradually stop using hormones, and serious condition can do artificial hip replacement. Sciatica can be treated with medication under the guidance of a doctor, such as vitamin B1 and other drugs that nourish the nerves. Sciatica and necrosis of the femoral head should go to the hospital in time, under the guidance of the doctor for treatment.