I had both hips replaced in 2008. TOTAL agreement with bionicycle about the upright bike and Schwinn Air would be a solid choice. Don't put it off, if you need it get it ASAP. Your body will adjust to the pain of the bad hip and start doing damage to the other hip and lower back. I have the ceramic on ceramic (Encore Hip) replacements. They are better than original parts!

I primarily ride single track and the hips have taken some serious falls and have had no problems at all.

In my experience with a recumbent position, it is all wrong for bad hips. I talked to sales people at a Sports Store, 20 somethings. They sold me on the recumbent position. It totally aggravated the bad hips and caused a ton of grief.

Good luck on the surgery. 3 months post surgery you will be riding like a maniac and disco dancing all night long.