Then I refer you to the extremely long and painful thread in which I discuss that you just have punch properly.
The thread was long, painful, and not particularly fruitful. The reader's digest version of my statements is, "learn to punch right and you have very little chance of breaking your hand."
For exactly how that is done, rather than retype if all yet again, I refer the interested readers to any number of period Pugilism manuals, some of which are referenced in the stickied thread in this sub-forum. But if you don't like 19th Century or early 20th Century English, then just read Jack Dempsey's description. He writes it very well.
Peace favor your sword,
Kirk