broken leg
I don't think there's really much you can do for him. I checked in wal-mart and they don't have any knee braces for pdf's.. it's a shame because I had the same thing happen to me, but mine was a little more dramatic. I'm up at tech and brought some froglets home over the weekend to sell to someone, and they were on my dresser. Saturday morning, I hear a huge crash and wake to find that my cat had knocked over the rubbermaid container that they were in and it fell five feet to land upside down on the floor. they were all fine except for one guy, who's leg looked to be broken. I thought he was done for, and put him in another container. When I checked on his leg later during the week and it was perfectly fine. He had gimped around for a couple of days but apparently it had healed ok. Apparently they can heal on their own sometimes. Just hope for the best and make sure he's eating. His weakened ability to hunt might affect his eating habits, and any other frogs in the tank will dominate during feeding time. You might want to separate him to monitor him, but be careful. Just hope for the best.
Good luck,
Kasey