My knee was so sore that could not apply pressure for a couple of days. It wAs swollen. The pain was not on the bone. Sometimes it moved around . It was my left knee. I took two alive two days in a row. I noticed the relief when I went to the bath room. It is better now I can walk on it but there is a little soreness. I did not hit it. My concern is that it may return. Can gas build up cause this problem