Pain after orthopedic surgery is mainly due to nerve damage caused by surgical trauma, as well as hematoma compression caused by bleeding, local tissue congestion, inflammatory reaction leading to increased tension, and these factors lead to nociception of local sensory nerves. Generally, the factors that produce nociception 72 hours after surgery are gradually relieved or even eliminated. Therefore, the pain after orthopedic surgery is usually around 3 days, and the pain will be relieved significantly after 3 days. 3 days or so, the bleeding has stopped, the hematoma can be absorbed mechanically, the inflammatory reaction will also dissipate, the local swelling and increased tension will also be relieved, and the trauma caused by the surgery will also be slowly adapted to the pain after orthopedic surgery.