Carpet and lino/tile/wood flooring can exacerbate Rex hock problems. They need a surface that enables then to position their feet/toes as they would on grass/deep hay. This is not possible on any type of hard flooring. Carpet can also be abrasive and it can wear away the fur on the plantar regions. Rexes have no guard hairs in their coat.
So what type of indoor flooring do your Rexes spend most time on ?
Do you insure that their toenails are always cut short and are they at all overweight ? I know it can be a challenge to keep a Rex at a good weight as they are usually so greedy !!