Once winter is over, move it outside and let it settle in for a few weeks. You should have lots of growth. Then once it is growing nice all over, trim back to the outline you want (And/or the branch structure you are after). Take the plant to a shady spot after trimming to avoid sunburn and watch the buds pop. All the old branches that then do not grow new buds, are dead and can be removed.
Tree is looking healthy now, and should not have any trouble with this treatment