The way to find out about knee effusion is actually relatively simple, in medical terms it is called the floating patella test examination, the floating patella test examination is to place the tiger’s mouth area of one hand on the position of the upper edge of the patella and push the patella forward and down appropriately, in the process of pushing you can use the thumb of one hand to press the patella appropriately. If the patella has a floating sensation means that there is a certain amount of buoyancy in the patella because there is more fluid in the knee joint, the floating sensation will only occur if there is more fluid in the knee joint. If there is less fluid in the knee joint, there is a more solid feeling when you press on the patella, which is a simpler way to determine knee joint fluid.