My crepe mrytle looks exactly as you described. I am starting to believe the top part is dead and may have to be removed. James

Mine looks the same way ! It is/was only about 6'tall and spindly, and has not bloomed because it is too shaded. It is "Tonto". I'm afraid I'd kill it if I tried to move it, so I am just hoping it will get tall enough to get enough sun to make it bloom. It is the first Crepe Myrtle that I have ever succeeded in growing.

My neighbor cut the tops off a row of crepe myrtles soon after the frost and hers are looking great. I only have rose of sharon and it looks sad. it's not dead but the leaves are just scattered along the branches.
vickie

You can scratch the bark on the part that looks dead. If it's green or yellow-green, it should leaf out. Yellow or brown will probably not leaf out. It seems like it should've leafed out by now. You might be better off cutting off the old trunks and letting the plant grow from the new shoots coming out of the base. Whatever you do, PLEASE don't flat-top the plants next winter. Let the crepes grow the way God(ess) intended.