Personally, I don't. I've tried using stabilized antler before, but to me stabilizing gives it an "unnatural" look and feel. As with most things that are stabilized, the stabilizing process does not eliminate movement (shrinking and expanding with temp/humidity changes) it only minimizes it.
Be careful of the type of antler you choose to use, some are "better" then others when it comes to knife handles. Those species that have a lot of pith and little sheath (elk, larger whitetail, and most of the mule deer) are more difficult to work with, and tend to shrink and expand more then those species of antler with less pith and thicker/denser sheaths (sambar, axis). Generally speaking, the larger the antlered animal, the less desirable the antler is for handle material.