I've noticed that cat leg amputations aren't usually done right at the knee-joint.
For example, with my cat, the shin bones were shattered and unrepairable, so an amputation was done.
The amputation wasn't done right at the knee -- removing the damaged shin bones and beyond. Instead, the amputation was done further up the leg, up on the thigh bone.
As someone who knows nothing about medical/pet science, I'm curious why the preferred option is to cut mid-way up a good bone (like the thigh bone), rather than preserve the entire thigh bone, and amputate at the knee instead.
In other words, why don't we see more amputations that have the thigh's knee socket-ball in tact? (kind of like what we'd see with a turkey leg at Thanksgiving :)