Repairing a Drywall Joint?

In my bedroom, the metal strip between the wall and ceiling has separated leaving a long running crack. My husband says the whole strip has to come off to fix that corner, but then that means I have to sacrifice my wallpaper. Is there anyway to reattach (glue?) the back of the strip, and then apply joint compound and then sand? Thank you. I can't imagine having to remove an entire room full of wallpaper I still like.

By Kelly