Risks may occur in any surgery, and knee replacement surgery is no exception. Generally, after strict preoperative evaluation and standardized surgical operation, the risks may be small, and not all of them, and allergies, infections, deep vein thrombosis, bone fracture, etc. may occur. 1. Allergy: It refers to the allergic reaction to fentanyl, dizocin and other fine anesthetic drugs, bone cement and other materials, which is manifested by the decrease of blood pressure, accelerated heart rate, and so on, and in serious cases, shock or even death may occur. 2. Infection: mainly refers to the infection around the surgical incision or prosthesis, with symptoms such as redness and swelling at the incision site, oozing fluid, and elevated body temperature. 3. Deep vein thrombosis: on the one hand, prolonged bed rest and lack of exercise after surgery lead to slow venous blood flow, on the other hand, large-scale surgery causes hypercoagulable state of blood, forming deep vein thrombosis of the lower limbs, which is mainly manifested as lower limbs’ edema, pain, and elevated skin temperature. 4. Fracture: mostly seen in patients with osteoporosis, fracture occurs due to osteotomy during the operation, causing knee joint pain, obvious pressure pain, swelling and so on. There are also risks of vascular nerve damage, non-healing of surgical incisions, and repeated surgeries in knee replacement surgery. It is recommended to go to a regular medical institution for targeted treatment under the guidance of a doctor, and to inform the doctor as soon as possible if there is any discomfort.