"Draining fluid makes it come back" — that's a myth
Your knee joint naturally contains a small amount of synovial fluid that acts as a lubricant to keep the joint moving smoothly.
When inflammation occurs in the knee, the body produces too much of this fluid, causing the knee to swell. This is what people call "water on the knee."
A common myth is that draining the fluid makes it come back more. This is not true. What matters is treating the underlying cause.
Cartilage wear, injury, or disease triggers inflammation within the joint
The tissue lining the inside of the joint reacts to the inflammation
The membrane produces far more fluid than normal
Accumulated fluid makes the knee feel tight and difficult to bend or straighten
Simply draining the fluid may provide temporary relief, but it can recur if the underlying problem remains. Proper diagnosis and targeted treatment can lead to lasting improvement. Ongoing inflammation has been reported to make changes in the cartilage progress more easily, so it is important to treat the underlying inflammation as well as drain the fluid.
"Draining fluid makes it come back" is a myth.
Draining fluid does not cause it to return. If fluid keeps building up, it means the underlying cause has not yet been addressed. Don't hesitate — get a proper diagnosis for the real problem.
But see a doctor urgently in these cases. A fever, a knee that is red, hot and severely painful, or sudden swelling that stops you bending or straightening the knee may mean septic arthritis or crystal arthritis (gout or pseudogout). Do not wait and see — get it checked.