The other day I was playing a soccer game and my knee totally gave out when I was trying to change directions. I fell and was on the ground and it felt like my knee was locked and not able to move. The trainers came to help me up and off the field. After a little they did some testing and my pain went down to a 4/10 and I felt like I was ready to play again. I did jumps and it hurt a little but the pain was manageable. The only weird thing was that when I fully straightened my knee it would make this really loud crack/popping noice and it felt like my knee shifted into place, it just hurt a little. For the last test I was told to sprint and turn, when I planted my left foot to turn my knee gave out again and I fell. I had the same pain and could not move it. Since then I have not put weight on it. It is pretty swollen and I can t bend it or straighten it all the way. The pain is like on the inside of my knee and more toward the inside (that's where the swelling is). today (3 days after the injury) i attempted to put some pressure on it and i could for a couple seconds before it hurting too much either from swelling or the injury.What could it be? Is it worth to get an MRI?