* A comfortable mat or bed or a couple of thick, comfy towels lining the entire bottom of the crate. (paw-rescue.org)
Tend to be noisier than plastic crates when your dog moves around, but this can usually be resolved by placing a thick piece of cardboard between the floor tray and the wire bottom of the crate (thehousebreakingbible.com)
However, it may be enough to simply make sure the entire bottom of the crate is covered by good padding (and crate pan / liner) and to make sure the collar is not loose and thus prone to getting caught on things. (paw-rescue.org)