That's what happened to New Zealand meatpacker Bryan Speers. While cutting meat with a band saw, he slipped and accidentally severed his left hand. He was rushed to hospital where the attempt to reattach his limb was hindered by scarring from a previous operation to attach the same hand after a previous accident!
Eventually surgeons did manage to successfully reattach his hand, and while he is expected to make a recovery, he will have to remain in hospital for quite a while while he regains the usage of his hand.
From the Upcoming ueue, submitted by Jake.