If a human hand were amputated with the sharpest surgical tools in existence and then was immediately reattached by clinicians trained in the most sophistocated techniques currently available, what would the result be?

Most likely, the hand could be reattached (not a guarantee, mind you!) and the owner of the hand would retain some or all of the function of the hand. However, it’s likely that all of the nerves, for example, wouldn’t be reattached correctly, so you’d lose some feeling in parts of the hand, some range of motion, or something similar.