Don't know anything about C-reactive P, well I didn't until Hern responded. Thanks.
I agree that it's a great idea to get several opinions, especially for different types of procedures. Phillipon is one of or maybe the most experienced when it comes to arthro techniques on the hip, so I would think that if he doesn't think arthro will be very useful for you, then it probably isn't going to be useful.
I went to an arthro ortho before landing on HR and he was fairly confident from the x-rays that the hip would become unstable if he carved too much of the acetubular rim away, which he'd have to do to get the ROM back. In addition, there was not a lot of cartilage left between the acetab and fem, so it wouldn't have gained me much. I suspect that might be one of the more common answers for the folks that have severe-enough OA to go with total/HR.
Good Luck