It's interesting that the hip is one of the joints that always seems to wear out as people get older. So many people over 60 need to get a hip replacement or even two. I guess people were not originally evolved to live as long as we do now.
I think it is usually the top of the leg bone, going into the hip, that gets replaced, and only rarely the pelvis area is replaced by an artificial cup in place of the joint.
I know a few people who have had it done, but I hope I never have to have the same surgery. It's supposed to be very safe and effective but the idea of having foreign material in my body like that creeps me out a little.