Sitting was an issue for a while for me.
My opinion (untutored, but educated by events) is that much of the support for sitting comes from the same muscles that have been compromised from the surgery and need to be retaught and restrengthened.
I think in time it attenuates, but for me it lasted a while. Standing was most comfortable, but sitting for long stretches was an issue.
Icing the area helps, but is clumsy.
One great help when sitting for longer stretches was my handy dandy bum icepack (TM) which was invented by my PT nurse and shown me when I got home from surgery #1.
- Take a small towel (I used a thin dish towel)
- Wet towel thoroughly, then wring it so it is wet but not dripping
- Fold the towel in half or quarters, whatever covers a 6 inch by 6 insh square
- Get an appropriate sized ZIP lock freezer storage bag
- Slide the towel in so it fits without buckling.
- Put in the freezer flat
This gives you an icepack that easily fits under you wherever you are sitting, even (and most helpfully) in the car. But it can be used anywhere else and doesn't put any pressure on the hip or leg.
It also melts in about ten to fifteen minutes, so you don't have to worry about frostbite. It also is thin, so it freezes in about the same time, so it gives your body enough time to recover and reapply.
It worked great for me, and was a comfort when I had a longer drive. You also don't have to re-wet the towel, it's a closed ecosystem. I had my little ice pack for a good two years and used it for other things once I got back to working out.