A pic would be very useful [member=155759]sheeponthebrain[/member] but normally best to tidy-up any breaks and/or splits (i.e. wounds) to produce clean pruning-type cuts to minimise chances of infection.
Every chance it will produce new upper shoots I would say, but watch out for a flush of suckers from the root stock which, of course, should be removed.
(Here's a contrary tale though: a clients plum finally died after 2-3 years of die-back. There were suckers aplenty which I repeatedly cut back apart from just 2, just in case they were coming from a buried bit of the variety rather than the rootstock - nothing to lose and I had in mind that some folk bury a variety/rootstock grafted union below ground ! Really not sure what they were/are; probably rootstock shoots actually, BUT they still produced some really nice-tasting plums last year !!)