Janet,
Today for Easter I went to a coworker's house for dinner and her mother, who is in her late 60s or possibly early 70s, is 3 weeks out from hip replacement surgery. She explained to me that they used titanium and they no longer cut through muscles, but rather push them aside. She was also a very active woman in her younger days, at one point playing in a hockey league (I think back in the 1970s, a time when women's hockey was practically unheard of, except in places like Philadelphia, where she lived). She was telling me about her rehab and how she has good and bad days. She is an overweight woman, and I can't imagine any extra weight would help with something new in one of the lower extremities.
My mother, who is 81, had a knee replacement but she struggles mightily with osteoarthritis which have wracked her lower extremities, so that making it up staircases, getting in and out of cars, etc. is a laborious chore for her. My mother is sharp as a whip mentally, and it bothers her tremendously that she cannot walk around like she once did. At times I can observe the anger and frustration in her face, especially when we go out to eat. However, having visited my parents last week in Florida for 6 days, I concluded she is dealing with it mentally better than she did immediately after her knee replacement surgery in 2007, or at any time since then. I think my mother had the attitude that the surgery was going to enable her to go out and kick soccer penalty kicks, but that is not what happened. My parents both seem very happy with their life in retirement in Florida, and they have aged well apart from the issues my mother has. I do not have a great deal of confidence that I will be able to age as well or live as long as they have- but I am okay with that.