An unclean shutdown can result in corrupted information being written into a directory structure. That effectively wipes out all record of a files' *name*. However, the exhaustive search of the filesystem contents done by fsck(8) can still locate the files *contents*. Rather than just throwing that data away the files are preserved by making a directory entry in the 'lost+found' directory. Unfortunately, since the file name is lost, the system has to make up it's own name, which it does based on the inode number of the file. That's a good choice, because it's guaranteed to be unique amongst all of the files on that filesystem.
Unfortunately there isn't going to be some sort of nice automated system you can use to restore everything to the way it was before the crash: if there was, fsck(8) would do that already for you. You're going to have to go through all of those orphaned files and by inspecting the contents try and work out what they were and where they belong.