Take a really, really close look at these 'twigs'. You may see the tiniest signs of growth (often dark red) starting at the nodes. Or, you may see growth starting from ground level. In either case, I would leave it for a while yet to see what happens. Once it does start to come into leaf you will see exactly what needs pruning because any dead wood will be obvious then.

Not sure what you mean by "tree". Is this a standard fuchsia on a tall stem several feet long? If so, test the branches for life by scraping a tiny bit of bark off with your thumbnail. If the wood is green under the bark trim them back to a good framework taking out weak and crossing branches and cutting back to about half their length. Fuchsias seem to flower better on softer new growth and actually grow more quickly than they do if you leave all the old wood on.Mist the bare branches every few days with plain water to encourage them to "break" (ie put out new shoots)
If the branches are dry and brown under the bark they are unlikely to grow but mist them anyway and don't give up on them for a couple of months as you never know. You don't need to do anything to the long stem, except that if new shoots appear on it rub them off. Or leave them to grow to about three inches and then remove and grow on as cuttings.

If a standard fuchsia is left outdoors all winter in this country it is unlikely to survive without protection, so I hope yours was under cover!