That sounds like a great result for Cleo. I've never heard of "Bamboo spine", but the idea makes sense. I've had to replace a couple of my litter boxes with ones that have higher walls because Sara wasn't squatting all the way and was peeing over the edge sometimes. So far she's been able to jump over the edges of the new boxes and get in, and the remaining box has a low front but is quite large, so so far, it's been working out okay.

I hope the Metacam keeps working for Cleo. Isn't it a great feeling when you see their pain get resolved?

If the knee is a stretched ligament, that's probably going to take quite a while to get better. As someone who has dealt with problem knees pretty much all my life, you have my sympathy! Just keep on keepin' on (which I know you do!).