I'd like to know more about what the doctors think the risks are. The pulling out of the drysuit story above is sort of telltale. But what are the doctors really afraid of? Cement cracking, no ligaments holding things together, bone breakage, dislocation? My doctor said the same thing that @A_B relayed... if you already do the sport you can go back, but taking on something new you need to watch it.
I had both of my hips replaced a bit more than a year ago and was skiing again 12 weeks after the second one. I am not a shortline skier but I have a far better chance to improve now than I did prior to surgery. Aside from strength, there were no issues, no pain and holy cow my range of motion may be better than ever. On another note, I was ice skating only 5 weeks after each surgery and playing hockey again after six months, and snow skiing after 9 months. My doctors only real concern is a broken femur.
I admit that it has been a lot of work and I am still working out the muscular tweaks and rebuilding stuff that I lost long before surgery, but the benefits far outweigh where I was coming from. Oh, and I'm 58.