If it is completely broken off no. If it is only partially broken you can try binding the two parts tightly together but I wouldn't be too optimistic.

As a last resort you could make a hole big enough to take the branch beside the parent, bury the end at least 9 inches deep, taking off any side growth to the main branch, mulch up high around the whole plant, water well with a weak solution of Tomarite and seal the cut with a piece of tape.

Dr B - how would that work, I'm fascinated.

Well Carol, it's as if you are taking a hard wood cutting. If you cut any shoots off the broken piece above ground, it will bleed, you will have some dieback as normal on those Acers, also the parent plant wil give it shade. It has worked for me before on many shrubs.

I'll remember that!