GS puppy with leg injury

Question
Hi!

my girlfriend found a very young (prolly 1 day old) german shepherd pup in the dumpster, his brother dead besides him. rats had chewed on his hind legs (paws) and tail. she took him to a vet immediately which amputated two mangled fingers on his right back paw and three on the left.

he's 2 1/2 months old now, about 7-8 kilos and he's developing a limp on his left back leg, the one with the three fingers missing. it's intermittent, sometimes he's limping, sometimes he's not. he recently moved from my girlfriend's place (apartment, carpets everywhere) to my house (tiles, hard concrete). i speculate that the hard surfaces combined with his increasing weight are causing the limp. he seems to love the grass in the yard and hangs out there every chance he gets.  he only has one finger,toe on his back paw and a somewhat mangled and scarred palm. as i felt around the injury, i got the impression that there are some bones missing too, or at least that there's something not quite right there comparing with his right paw and the back feet of my other dog, an airedale terrier. he's not crying or showing any clear signs of pain, though.

will it get better, worse, is there anything the vet can do for him?

Answer
Hi,  I think the hard surfaces could be causing him some pain, also he is going through growth spurts, so with the weight changes, his feet will have to suffer a little to adjust to his growing.  He could also be getting something called panostitous.  It is basically like growing pains in kids.  Very common in larger breed dogs like shepherds.  Normally you don't see it until they are a little older (around 10 months to a year in males).  I would definitely keep him on soft surfaces as much as possible.  Also watch his exercise.  Don't let him do too much at a time.
When he gets older he may get arthritis, if so you can give him glucosamine, but otherwise there is really not a lot you can do.  
Hope this helps,

Dawn