Not at all. I think earth spear is ridiculously overrated, it has almost no feats (and the "diamond hard" is from the notoriously unreliable databook, in other words meaningless). Further to that, even if it isn't, Tsunade has multiple ways of trashing Kakuzu.
1) She's got lightning affinity, so there goes Earth Spear,
2) Her Medical jutsu attacks beneath skin level, going for the nerves, so hard skin doesn't protect from it,
3) Her physical strength alone is shown to trash things tougher than Earth Spear, like being able to crack Susanoo (remember that thing that tanks Kirrin, even when it is in the invisible stage, something that would one shot Earth Spear regardless of affinity)
4) She can reverse his electrical impulses, which his tough skin is again no defence to.
That says nothing about the giant slug that shoots huge quantities of acid, or her physical strength that will let her bat him around effortlessly (or just poke his frickin eyes out). I get annoyed by Kakuzu fans though... if earth spear was half as tough as they claimed, Kakuzu wouldn't spend so much time dodging attacks, or be getting nailed destroyed by Rasengan didn't have affinity advantage, or losing multiple hearts to frickin TenTen).
Given her chakra levels, which are enormous, there's no reason she couldn't make a Kage Bushin, send one to deal with Hidan (that'll take all of what, 30 seconds), and then go finish off Kakuzu. She's one of the better hand to hand combantants we know, so there's no reason to think Hidan is hitting her, and once he's disarmed and ripped into bits, she can toss him into different mini-katsuyu's for safe keeping (not before reversing the electrical impulses in his brain so he can't say anything annoying for the rest of the fight).
The she goes and finishes off Kakuzu, who is strong, but has nothing to take down someone with Tsunade like durability and recovery. He also gets hit by fodders alot, and is not especially good at close fighting. Fight over. Problems?