Arthroscopic knee surgery is usually performed without fluid accumulation in 3 to 5 days. Knee joint trauma and many knee pathologies require arthroscopic surgery, after which a drain is placed to drain exudate and blood from the joint; it is usually set aside in 3 to 5 days when there is no fluid accumulation. After knee arthroscopy, a drain will be placed in the joint to drain intra-articular exudate and blood, and to observe the amount and nature of the drainage effusion, which will gradually stop in 3 to 5 days; the observation of the drainage effusion is very important to determine whether there is any post-operative bleeding and infection and other complications through the amount and nature of the effusion. After surgery, the knee joint should be closed to reduce the amount of activities, which is conducive to reducing the production of joint effusion and accelerate the absorption of fluid. If you feel unwell, you should go to the hospital and consult your doctor.