Wow you’ve been thru a lot more tests than I, but I have had very infrequent total loss of muscular control/buckling of a knee (it’s happened with both) that just happens out of the blue. No pain, no forewarning, very disconcerting! It lasts for a brief period and then I’ll get the knee back functioning. I can’t walk while it’s occurring. I’ve mentioned it to my physicians and they don’t know what it is. I’ve got cerebellar ataxia with vision (nystagmus)) issues that cause dizziness/vertigo, stability and balance issues, tremors and loss of fine motor skills. I’m doing ok with all of that but I had to respond to your post, as it has been confounding and quite frustrating for me. All the best to you in finding your way through all this!

MarkE