About half an hour ago, I was running upstair to get the phone. It was dark and I hit the top of my knee against a fairly thick wooden chair at full speed. I was sprawled on the ground, clutching my knee in pain for about 10 seconds, after which I walked fine, even balancing on that leg perfectly. There is small bump at the point of impact, ever slightly pinkish, it feels soft like a muscle rather than a bone. Touching the area, it feels fine, no pain, everything feels the way it should be. There's actually no pain when I walk, I feel a slight pull when I lift me leg up to my chest, and when I do a sitting down motion I feel a stronger strain, maybe a little crack as if I was cracking my knuckles. So I guess any sort of fracture is out the window, but what does it sound like this could be? I always like to know the worst case scenario.