Sorry, but going to a club on crutches is utterly stupid. Everywhere has loads of stairs and you'll inevitably get people trying to take the crutches off you. Plus as clubs are so cramped, you're bound to get someone knocking into/stepping on your cast and risk doing further damage. Would you even be able to use them properly if you're drunk?
I broke my leg and was in a cast for an entire term, I was so tempted to go out. My closest friend from uni was really encouraging it and offered to keep an eye on me, but at the time she was the sort of person who'd go off and get with people. So I knew that i'd just be ruining her night, and I doubt i'd have enjoyed myself either.
You can still go to the pub, go out for meals, go round peoples houses or even just sit in the kitchen and talk to people. Obviously you can still go to your lectures as well. It's not like you'll be a social outcast!