Hello
@Ballina I can't explain why your nee suddenly swelled. Has it improved again?
My 8-year-old knee suddenly swelled up and became very stiff about a month ago, after I had been sitting with it bent for too long. It would hardly bend at all at first.
I spent the following three days resting, while icing and elevating that knee and the swelling and stiffness gradually went away again.
I did go and see my surgeon, who could find nothing wrong with my knee and his possible explanation was that keeping my knee bent for too long had restricted its circulation and when I straightened it again the blood came rushing back fast, along with some additional fluid, so the knee swelled up.
It would probably reassure you if you saw your surgeon, just to check that your knee is all right.
However, it is summer and it may be that the heat and humidity are causing you to retain fluid. That's quite common, as many people suffer from swollen ankles in the hot weather.