My first ever cat had legs similar to that when he was born. He was the smallest in the litter, but we never braced his legs, just massaged them every day, and gently moved them back into position when he was feeding as much as you could and it just got better a little bit every day. He did have a tendancy to drag his back legs behind him and had bald feet for a few weeks, but as he grew they did untwist.

A breeder friend had a kitten with a front leg like that. It also came right by itself, although she did bandage it when he was about 4 weeks old just to give the leg a bit of strength, but she only used that vet wrap and some padding, it wasn't braced.