My son who is 13 was playing basketball, set a screen and a smaller player ran into him and he fell down. Said the players knee hit the inside of his knee right below his knee cap on his right leg. He left the game, iced it and tried to play, but he ran about three times down the court with a limp, so we shut him down. Right now, about four hours later, he can t put much weight on the knee or straighten it and he says the back of his knee, not the front hurts, but the swelling is on the front of the knee.