After the hip surgery the sciatic
pain disappeared. My guess is that the hip
pain was altering the way I walked, sat, stood, etc, which can easily lead to pain elsewhere in the body.
If you've been on mtx alone in the past and it didn't work, try it again and combine it with one of the newer meds like Enbrel or Humira. I was on mtx alone for a long time and though it worked relatively well, I'd still get flares and need occasional prednisone.