I've read studies that say braces don't do anything and studies that show a marginal benefit. However, with all the time and money that I've spent on surgery I'm willing to use the brace even if it only helps the tiniest bit. At the very least it's a good reminder to take it somewhat easy.
Like uglymoney said, work hard at PT! At a minimum I would say plan on 1 hour a day of exercises, stretches, mobilization, etc. If you can dedicate 2 hours per day that would be ideal.