knee pain/injury?

[dadong72]

Hello,

Hurt my knee during a football match yesterday. I think I kicked the ball at the same time from opposite directions with another guy (who was massive), and the shock went straight up to my knee.

I don't think its serious, because I played the rest of the game and walked 4 kilometers to get back home after that and it didn't hurt at all as long as I kept it straight, but I had to limp a bit.

The only area that hurts upon contact is on the side of the knee (not the side of the kneecap) but when I twist it a bit in some ways then a jolt of pain goes through the whole of my kneecap (which worries me).

The next day, the pain is worse and its stiffened up. There is no visible deformity either, so once again probably not serious, but I was wondering what type of injury this is and how long it could last.

Thanks