I'm not completely sure what your question is, but am going to assume that you want to know if a hip placement would be a good idea for you? If I'm wrong, feel free to ask again and I'll try my best to answer.

I've had both hips replaced and it's wonderful. No more pain, and no more stiffness and did I mention no more pain? My brother-in-law had one of his hips replaced last year and is now running around after his three-year-old twins. Joint replacement can be the solution when nothing else is helping.

That said, personally I'm fairly conservative when it comes to surgery, preferring it to be the last resort. Not everybody is on the same page as I am, but there you have it. How much pain are you in? How much does your lack of flexibility and/or pain limit you? Are you doing okay, with the exception of e.g., sex and the annual Pap smear? If you're doing all right in the other ways, I want to assure you that a little creativity will solve the problems in both sex and the Pap smear (despite my hip replacements, I can't spread my legs very far and still manage to get a Pap smear every year). If your doctor doesn't have that level of creativity when in comes to your annual physical, maybe ask for a referral to a gynecologist or find a doctor who's willing to think creatively. Within the next month or so, I'll be writing a post that deals with RA and sexuality, so look for that. In the meantime, there are a number of resources available on the Internet (like this page showing a number of different positions that accommodate various disabilities) and a number of books on sexual health and disability in larger bookstores (try doing a search on Amazon.com).

I'd suggest that you talk to you rheumatologist about your concerns and how the lack of mobility in your hips affects your quality of life. Depending on how severely you're affected, it may be time to consider the option of a hip replacement.