I have had left knee pain off and on for years and several years back a procedure was performed where shaving of some bone spurs was done. my knee pain has come and gone since. however, about 1 year ago, i injured it by lifting my leg and with some force met the corner of a wall with the top of my knee. x-rays showed no break. doctor prescribed pt, which did not help. pain has continued/worsened. there is now bruising (black and blue) on the inside of my knee. is this worrisome? knee pain?