Signs and symptoms typically include:  Swelling. The skin around your kneecap can puff up noticeably, especially when you compare the affected knee to your other one. Stiffness. When your knee joint contains excess fluid, you might not be able to bend or straighten your leg completely. Pain. Depending on the cause of the fluid buildup, your knee might be very painful — to the point that it's impossible to bear weight on it. 
signs symptoms typically include:  swelling  skin kneecap can puff noticeably  especially compare affected knee one  stiffness  knee joint contains excess fluid  able bend straighten leg completely  pain  depending cause fluid buildup  knee painful — point it's impossible bear weight it
swollen knee