Hamsters need to run about 3 miles a day/night to keep healthy. They normally do this at night, but some hamsters can become addicted to their wheels (sounds odd, but it's the truth). By the sounds of it, this is what has happened to yours. I'd leave his wheel in there at night so he doesn't get bored but take it out sometimes in the day so he goes on it less. This will also help his leg - if he's running a lot on it and he only has 3 paws, the other will be under a bit of pressure to keep up, as it's not as sturdy. If you're really worried about his leg and it shows signs of irritation I'd take him to the vet. Better to be safe than sorry. Hope I've helped and I hope your hamster is okay
Figure out what's making his wheel noisy and fix it. It's possible to have a quiet wheel. I know because that's what I did. It lasts a little while. Then fix it again. Doesn't take much. Kinda funny too when the little dude is truckin and not a sound is heard.