I don't know anything about the damage but I did opt for jpouch surgery 7 years ago because I began fearing the long term side effects of steroids more than I feared surgery. Along with bone issues prednisone can also affect the eyes so be sure to have annual eye exams and let your optometrist know of your pred history. As a former pred user I urge you to find other options to pred if you flare again. I was fortunate to have zero pred side effects after 2.5 years of consistent use; others aren't as lucky.
Sue