I fell yesterday after tripping over a shoe. I tried to correct my balance but couldn t. I ended up on my left knee with carpet burn and a bruise on the anterior surface of my left knee. I am on Coumadin so am prone to bruising. my kids got me back on my feet (despite my weight of 306) and I walked down the hallway to my chair in the livingroom with no difficulty whatsoever. about 45 minutes later I went to stand and had an intense searing pain in my left knee that I fell back into the chair fully aware that I would be completely unable to get myself up. my knee then was in pain (10 out of 10 with movement 7 at rest) and has not changed since. I can not put weight on it despite the pain med I received from a subsequent er visit. xray was normal and I was diagnosed with a knee sprain after very little actual assessment by the PA on duty. I do not remember a popping noise with the injury, only fear, and some pain with the fall. I cannot lift my leg up and my pain when I try is in the posterior lateral aspect of my knee. I also have aching down my anterior knee about 3 inches distally and a burning pain posteriorally (spelling?) up my my thigh (sciatic nerve area).to my buttock. what does this indicate?