I fell on my left side on a sidewalk 6 weeks ago. I sustained a broken elbow in the fall. My left knee was painful and severely bruised from just above my knee to my toes. I am able to walk on that leg, but I limp and it is somewhat painful. Not severely. On my knee, it is still discolored, it is swollen and feels spongy. It is also numb over my entire knee and about 4 inches down my leg on the outside. What could be the cause of all this. I had an xray of my knee, but it was negative.