As you prob. already know, it's not just the claws that are surgically removed, it's the first digit of the toe. The bone can grow back and most often does which is one of many reasons it's been outlawed and where not outlawed, some vets just refuse to do it (except those in for the money)...
A friend of mine had a declawed cat that this happened to, she was leaving spots of blood everywhere she walked/limped where the toe was growing back and had to go back into surgery at age 13! Too old for invasive surgery but it had to be done.
When they are declawed, it's not easy to know if enough has been removed to prevent regrowth. It's pretty much hit or miss from what I understand...