Is there any way to "repair, rebuild, recalibrate, etc." the MySQL tables?

The reason I ask is that I have a forum set out for FAQs only so 1 Thread = 1 Post but one of my forums states 12 Threads | 11 Posts. I want it to display correctly - 12 Threads | 12 Posts.

I also have a forum that displays 1 Thread | 1 Post but there are actually 2 threads in there.