Signs and symptoms of water on the knee typically include:

  • Swelling. The flesh around your kneecap may puff up noticeably. This swelling is most apparent when you compare the affected knee to the normal one.
  • Stiffness. When your knee joint contains excess fluid, you may not be able to bend or straighten your leg completely.
  • Pain. Depending on the cause of the fluid buildup, the knee may be very painful — to the point that it's impossible to bear weight on it.

When to see a doctor

Seek prompt medical attention if:

  • Self-care measures or prescribed medications don't relieve the pain and swelling
  • One knee becomes red and feels warm to the touch as compared to your other knee
Jun. 16, 2012