Earlier this afternoon a 70 Labrador Retriever accidentally ran into me and hit the front of my knee. I was knocked down and unable to stand initially. After a few minutes I could stand, bear weight and walk around. I have iced it and there doesn t appear to be swelling or bruising. However, when I walk it feels a bit unstable and there is pain (moderate) that begins behind my knee and goes up the back of my leg. Your thoughts on what the injury may be and what my next steps should be.