Why is Macduff able to kill Macbeth?

Macduff was able to kill Macbeth because of a prophecy delivered by three witches. The prophecy foretold that no man of woman born would be able to harm Macbeth. However, Macduff was not born in the traditional sense, but instead was "untimely ripped" from his mother's womb. This technicality allowed Macduff to be the only one capable of killing Macbeth.