Ive had a couple incidents of leg injuries, there's so many frogs and toads where I am they tend to get stepped on frequently. Anyway you can try splinting the leg, its not easy but I've seen pics and vids with minimal instructions on the internet that have had success. I had no such success with splinting but simply took the toad in, keep him in a very simple tank with paper towels, a shallow water bowl and a small plastic, opaque cup for him to hide in and fed him calcium dusted crickets then gave him time to heal. It took several months but he's completely fine and in the beginning couldn't use it at all and held it up or propped it up on things.
he's now a permanent pet because he stayed with us so long but I had 4 others that accepted him well
Good luck