Providing you can sit down to do your duties, then I must be the only one who thinks that it's totally reasonable to work with a broken leg. By all means, take couple of days off to get over the immediate shock and pain, but if you're an office worker I would say that it's entirely fine to work!
Of course, if there are elements of your job that require you to walk around a lot, then your work should come up with an alternative, but I'm guessing that the majority of your duties do not require this.
I've been in a cast and on crutches before, but because it was a desk job, I could sit down, pop a couple of painkillers and work entirely normally....