I'm not sure whether or not this is connected with BFS. Ghayes, it's pretty interesting that your knee buckling only started after your BFS. I can't think of any reason why that might be, but then again there is no explanation for the random twitches we get either. Anyway, like all problems BFS and otherwise, if it's something serious, it'll start happening more and more frequently with increasing severity. And, if you keep thinking about it, it'll keep happening even though there is no problem present. For example, when I manage to take my mind off of bulbar ALS and eat food, my swallowing feels completely normal and natural with no coughing or choking, but as soon as I start thinking about it, I become painfully aware of my swallowing, the swallowing itself feels very awkward, it feels like food and liquid is going down the wrong pipe, I start coughing, etc., and this is all psychogenic! This is why anxiety is the underlying problem behind most BFS symptoms other than muscle twitching (and in many cases, that's due to anxiety too).