Yes they can get in back in but any damage that gets done along the way is irreversable. It is called Luxating Patella. Both my dogs have it in both their rear legs. Roxy just had surgery and she is having surgery again b/c her right leg is luxating again. TJ will have surgery too, but not for a few months. Please do a 'search' on YT for Luxating Patella, you will find a lot of really good and helpful information. Also, the best advice I could give you is to please if you are going to have the surgery done - Please Have an Ortho Specialist do the surgery. You can PM any time if you have questions or concerns.