In reply to Steve nevers:
If you're concerned you're putting on weight then maybe the best thing is to modify your diet rather than exercise. The high fat low carb diets seem to work pretty well for people, or the more extreme version which is the ketogenic diet. Dave Macleod was having success with this after an injury stopped him running and he couldn't keep the weight off any other way.
In terms of exercise the high intensity interval training is said to be as good as, and takes much less time than, traditional cardio. You couldn't do sprinting but working around your hip find which exercises you can do. You really want to involve major muscle groups to get your heart rate right up, so compound movements would be better, pull ups, dips, and whatever core exercises you could do (those lying or sitting down, or hanging from a bar might be OK with your hip). Otherwise some kind of circuit training with minimal rests. Swimming would be another option.
Plenty to choose from, so it really depends what your most motivated for. If you don't keep it up it won't work.