It usually takes 2~3 months after femoral head replacement surgery to be able to sleep on the side of the affected area. After femoral head replacement surgery, it is usually recommended not to sleep on the side for a short period of time, mainly to prevent the lower limbs from crossing over, which will increase the stress on the artificial joint, thus causing posterior dislocation of the femoral head. It usually takes 2~3 months to recover from the surgery, waiting for the surgical site to heal, restore normal blood supply, and normalize the function of activities before adopting the side-lying position. After femoral head replacement surgery, patients need to sleep on their backs, but when lying on their backs, they must avoid crossing both lower limbs at the same time, or else it will easily lead to excessive flexion of the knee and hip joints, which may lead to dislocation of the hip joints. Patients need to stay in bed in the early stage after the replacement surgery, which is easy to cause bedsores, constipation, and even the formation of deep vein thrombosis of the lower limbs, etc. It is recommended that patients and their families should do a good job of daily care, and follow the doctor’s instructions to strictly comply with the postoperative precautions.