Hello, I am. 70 yr old woman, in general good health. In the recent past I have had two or three instances of a sharp pain in my leg. About half way between ankle and knee, on the inside of leg. I weigh about 130 lbs and am 5 4 tall. I do yoga exercise 3-4 classes a week, of various forms. Pain feels like a knife stab, most usually happening when I get up from bed, and find it hard to step down on floor. Usually stop to rub area, and it begins to feel a little better. Has returned more frequently recently. any ideas?