My leg has been feeling like it is about to collapse when I am walking off and on for about 3 months. I am always able to catch it so that at worst it is a just a stumble. Sat. I was leaving a friend's house and as I stepped down the stairs on the porch my leg collapsed and I ended up in a heap on the lawn in a fair amount of pain. The fall wasn't that bad - only 2 steps - but my left leg is really sore. I broke my left leg in 4 places and almost lost the leg 30 years ago so it doesn't bend past 90 degrees. The fall attempted to bend it further. The scary part is the leg collapsing. My symptoms, pain, numbness, etc. started 2 years ago. This is just the first fall I've taken because of PN and I'm a little shaken. My DX is Idopathic Polyneuropathy, which means they don't know what's wrong.