A few hours ago, I was struck on the inside of my left knee during a contact sports game by the knee of another player who was running full speed toward me. I did not hear any distinctive popping noises but went down to the ground immediately and was not able to bend/move my leg because of intense pain. Within fifteen minutes, the pain had begun to decrease it and within 20-25 minutes I was able to lightly walk on it. I am trying not to put too much pressure on the left leg because of pain that occurs to the right (inside) of my kneecap. I can extend and bend the leg, but I cannot straighten/bend the knee all the way because of a feeling of "pressure" when it approaches either extreme. Just sitting in a chair with my leg slightly bent and resting on the ground, I can feel a slight sort of pressure and some pain/discomfort on the inside side of the knee. If I press about an inch to the right (inside) of the middle of my kneecap I can feel a soreness/pain. There is no swelling/bruising as of yet, but I have been icing it.
Can anyone give me a likely diagnosis for this injury? Best answer will be chosen, most likely one that explains why you make such a diagnosis. Thanks for the help.