Oooh been there done that. As in, been the one with the broken leg. Good things are books, magazines, movies, cards, flowers (especially ones that last a long time), sweets, etc. Better things are homemade baked goods, homemade crafts sets for things like learning how to embroider, homemade cards, etc. The BEST things are frequent visits (but always with notice!) and consideration! There's nothing worse than making her feel bad when she asks you to get something for her.
How about a t-shirt printed with something along the lines of "No, I can't get it myself, my leg IS broken!"?
Love this idea!