It's more about your bones than your muscles. Guichet recommended that his patients developed muscles in their legs before surgery, but I wasn't able to find a paper on the reasons for that. He did mention, though, "wide bone, heavy, muscular, caucasian type patients" have an easier time with the healing.
You want to maintain a great diet until (and after) your surgery. You don't want to have subpar calcium, vitamin D and vitamin K intake.