Another worry, My wife and I went out for lunch today, nothing unusual happened, we returned home, I sat in my chair for a while and on getting up my right leg collapsed under me. Six hours on its still doing it, I usually walk with a walking stick but I'm worried about falling so I'm using two for now. There is quite a lot of pain behind my knee, I think because I keep getting up to try it out again. Could this be related to my lower back problem (CMT) or perhaps my right replacement hip ? I live in America now, This will be expensive.