Hi Anna,
I have been following your story, and am so happy that you are at last on the happy road to recovery that allows you start thinking about skiing. As you probably read, I have a resurfaced hip that I ski hard on; 6-8 hours a day seven days a week all winter, and I am very happy with it. I know your question was about THRs, and though I do not have one, I know and teach many people who do. Where I ski, there are at least 5 or 6 full time ski instructors with one or two THRs, and at least the same number of full time ski patrollers. I have had at least half a dozen ski students with THRs, many bi-laterals. Of all those people, I know of two that are going in for revisions this year, but that is after about 15 years each of skiing and other high level activities. I have seen a couple of dislocations on the hill, but these have always been with small heads; probably 28s. Having conferred with a number of hip surgeons about how to advise my ski students who have THRs, here is the consensus they have passed on to me: People can ski safely with a THR. Avoid racing because of the possible vibration crossing chatter marks. Avoid hard landings. Moguls can be skied only if you have the skills to ski them smooth as silk with no impacts. Same with skiing off piste; it is all about the skill that a person has to deal with the conditions. One friend of mine owns a heli skiing operation up in Canada, and he guided in deep powder for years with a THR while carrying a heavy pack.
One minor thing to watch out for. Be careful of reaching down and buckling your boots if you are on your skis. Because of their flexibility, many women do this by rotating their knee far to the inside so that they can sink down to get leverage to tighten their boot buckles. A friend who is a strong racer dislocated her hip by doing this. Better to sit down on a bench somewhere to buckle the boots so that it does not involve any contortions.
I hope that you are able to enjoy getting back into the mountains with your THR, I know lots of people who have.
John