Quote Originally Posted by Atlas View Post
The top open litter boxes are ok for smaller/younger cats. But I've heard they can be bad on the joints. Jumping up from a loose footing like litter can be hard on them, as well as the idea of jumping down into it and landing in poop.
I would like to kindly disagree with this. Firstly because the box isn't deep enough for them to have to jump in or out of the box - they can simply climb in/out. My kitty uses the part away from the entry hole to do his business and doesn't step in his own waste (which he buries anyway).

But secondly because physical activity helps keep muscles strong which actually helps reduce strain on joints and allows for continued activity even in the face of arthritis. It's why we recommend swimming so much for doggies with osteoarthritis in their hips due to hip dysplasia. When many pets get degenerative joint disease it's due to changes that were there since a young age that predisposed them to arthritis and not from repetitive motion injury (not that I think jumping in and out of a box qualifies as that in the least).