Usually, when you trim the rootball you trim off some of the foilage on the plant. There is thread on here about it. You should trim about 1/3 of the green foilage when trimming the roobtall. But you weren't trying to trim it. It just broke, so it prob didn't need to be transplanted yet then.

This what I do with my mother plants. Since I don't want to transplant them into ginormous pots, I trim the rootball, put fresh spoil in to replace what was there. Then trim her up. I only do this right after I butcher her for clones tho.

This may have helped you, it probably didn't though.