I read him quoted as saying it would be titanium. Also, he is working with surgeons to do a procedure that at least considers his after surgery cycling goals. One issue is not just the hip replacement, but the long term consequences of cutting through muscle, but depending how they do the incision they may be able to minimize the post-surgical muscle weakening. My husband, after having his own hip surgery, predicts he won't be able to come back, but I think if he could win the tour on a bum hip, who know how he'll do with a good one, albeit artificial. He'll be the first bionic cyclist!