Two or three weeks ago we had some friends over, and in course of things Phae got stepped on. Her foot, specifically. She gave a little yip and limped away, did the whole holding her paw up thing, but two minutes later she was walking around normally like nothing had happened. We didn't worry.
Couple days later, her foot looks funny. The middle claw was a little crooked, and the toe was swollen. We took her the vet and they x-rayed it. The toe wasn't broken, but looked infected. They gave us a round of antibiotics. That didn't have much effect, but we did the full course. On Saturday (with two days of antibiotics to go) the toe formed a pustular head and began to discharge. I probably should have taken her in then, but figured we should let the antibiotics finish their course. Also, by now, the middle claw was discolored near the base, and was basically sideways.
Turns out the nail was broken off at the root. When they cut the toe open, they found the bone itself was pretty infected and had to amputate up to the first joint. It's described as being pretty much the same operation as declawing a cat.
She's home now and recovering well. She can't climb stairs, so I spent last night on the couch in case she needed something. Probably there tonight, too. She's pretty good about the bandage, but we've had to cone her, anyway. Such a pie.