Age 71. Stumbled hard and fell onto sidewalk three days ago. Knee hit surface, but not very painful. Next day a bit worse and from then on if I walk a while eventually leg aches a lot in area of knee. But no sharp pains of any amplitude on specific movements, or limits in use - just the very strong ache beginning after about one hour of use, as with walking, and a slightly unpleasant feel to the knee even when strong ache has receeded. This ache continues after the exercise or use. Should I give the situation some time, or go to a orthopedist pretty soon?