broken ankle, help??

I have been trying to lose about 10 pounds, which is the weight I have put on since the holidays and sitting around with a broken ankle for the past 6 weeks. I will not get my cast off for another 3 weeks, and I still cannot put weight on the leg. I would like to know is there anyway to lose weight, with this disability. Or atleast being able to maintain the weight that I am now. It's so frustrating to be forced into a sedentary lifestyle, when you want to lose weight.