HI. this could be usually one of two things in my mind. the most common is a quadriceps tendon tear. these can come on suddenly and without warning or by overworking the muscle, especially in women over the age of 40, I will attach a webpage on this problem, the best thing to do is get a knee brace for a few days and see if that helps the problem if you take pressure off the tendon, and use a NSAID like aleve.
the other thing that comes to mind has to do with Hunter's Canal, It is called adductor canal syndrome, and is usually found in athletes. there is a spot just above the insertion of vastus medialis, were the saphenous nerve exits to innervate around and then below the knee. This can cause a sudden stabbing pain which is occasional. There is a muscle, sartorius, that lies over the nerve and sometimes by crossing you leg, you can irritate this area. I will attach a webpage on this. The treatment is usually just NSAID like aleve. IF it does not get better, you can inject the area (do a nerve block on the saphenous nerve)
please get back to me if you have questions regarding these possible diagnosis, I cannot accurately diagnose your condition online, but might be able to give you some direction. Dr Frank T
Should I see my doctor - if not now, how long should I allow for symptom to clear up before seeking medical attention if it does not.
Both of the options you have presented lead me to believe that this is not something I should get overly worried about - the level of pain is what has me worried - If I am not holding on to or near something to hold on to when the pain hits it drops me to the floor.
Since writing my initial question the stabbing pain has happened 3x more/