Knee surgery is usually minimally invasive and knee replacement surgery, as well as knee fracture surgery, which also has a swelling time ranging from one week to six months. Minimally invasive arthroscopic surgery is usually followed by a certain amount of fluid and swelling, which will be significantly relieved after two weeks. Patients are usually required to apply elevated brakes, strengthen quadriceps contraction exercises and ankle pump training to promote the swelling of the knee to subside after surgery. In the case of knee fracture surgery, the swelling time is slightly longer, for example, tibial plateau fracture surgery, the swelling time may reach 2-3 months. In the case of knee replacement surgery, the patient may have swelling for about 2-4 weeks after surgery. If swelling is suddenly noticed about 10 days after surgery, it is important to consider ruling out the formation of deep vein thrombosis.