When my wife had her tumorectomy, they had to excise her entire gluteal process because it was all involved with the tumor. The plastic surgeon moved a flap of her outside quadriceps up and attached it to her hip in place of the gluteus. Dr. Gallus explained to me later that the purpose of the flap was twofold. The secondary purpose was to attempt to replace muscle function so that Lina would be able to walk somewhat normally again. The primary purpose was to fill the void. Dr. Gallus explained that, when a large piece of muscle is excised, the body attempts to fill the void with liquid, which leads to sepsis etc, unless that space is filled with a replacement muscle. I think their choice of muscle for the replacement is based on availability and size equivalence. At any rate, Lina's first flap failed because her hip had been too recently irradiated and hadn't recovered. So, she ended up getting another flap drawn from her hamstring after the quadricep flap failed. She did eventually learn to walk on it pretty well, but not with lots of strength. She had to climb stairs one-legged, but she could brace with the left leg while the right did all the work.
Kim from Georgia, who's "drifting" a little while deadlifting is kicking big ass and needs to keep it up. She's a hero.