Here's what the vet said, my comments in parentheses: Pepper was found to be pregnant during her spay, likely about 30 days along. This may very well explain her voracious appetite. (The examining vet didn't agree with me that she was pregnant---This may also be because she is soooo skinny that it was hard to tell. I'm thinking the worms and the pregnancy were eating her up.)

We could find no evidence of fracture of either hind foot on x-rays and the knee was stable under anaesthetic, meaning the cruciate ligament is not ruptured, or at least not enough to cause instability. (That's all good news, but she still limps and holds her left hind foot up and often bunny hops as though that hind foot is bothering her. She has cried in pain and tried to bite, too, when I've touched the back foot. So, who knows what exactly is going on.)
She does have mild hip dysplasia on the left side, which may be causing her to limp after increased exercise (I'm wondering if the accident made this worse).
Because of the dysplasia, it will be important to keep Pepper on the thin side--obesity puts more pressure on the joints and increases arthritic symptoms. It would also be a good idea to start Pepper on a daily Glucosamine/Chondroitin Sulfate supplement to help decrease her arthritic symptoms. As she gets older more medication including anti-inflammatories like Metacam may be required to keep Pepper comfortable and pain-free.
(I saw the injuries to her feet when she had just fallen out of their truck and been run over---her hind foot looked really, really bad. There has to be something there---but because it's been five months, the injury may have healed in a way that they can't find anything wrong with it. This doesn't mean it isn't hurting her daily. Poor girl.