Why no upper body work? There is a guy at our gym that broke his leg. He just train his upper body. Humps around on his crutches with a stiff leg. That don't stop him. Did your doctor tell you not to train at all?
When I couldn't walk because of knees problem, I did massive upper body training. Crunshes,sit ups, Dumbbells being sit:-) you can find some work out that are ok with your condition and continue to train.