Orthopaedic interview offers are always given out later than for most of the other specialties. Dont panic just yet. I remember what it was like last year and it is very stressful, but try to be patient. The vast majority of your interview offers will be coming in November & December.
I was obsessive compulsive last year about recording when I got my interviews and after seeing your post I thought maybe some applicants might find the following info interesting. Keep in mind that this was just one person's experience. I mainly applied to the midwest and it seemed there was some regional variation.
My interview offers broken down by month:
October: 12%
November: 63%
December: 22%
January: 2%
Percent of Programs which I never heard from: 14%
People obviously heard both earlier and later than me, but the thing you could take away from this info is that there is still plenty of time. Also, dont get worked up too much if someone gets an interview before you do and you are offered one later. This happens a lot and from my limited experience it seemed that this may mean something at some programs and absolutely nothing at other programs. There were definitely a few places where I felt the interview process was relatively meaningless, but it seemed like at a lot of programs the interview was your chance to make or break yourself (at the very least it seemed like the chance to move up or down a little bit on the good ol' rank lists). Also, I would tend not to be too pushy, but if a few fellow applicants have heard from a program it probably cant hurt to call and check the status of your application in a nice manner. You may find out if your app got a yeah or a neah (sometimes it is just nice to know regardless) and might even get your app looked at again because you are expressing interest in the program. This is just my two cents. Feel free to pm me with any questions. I really feel for all those going through it. It is a painful and stressful process, but it is also a lot of fun getting to meet all of the other applicants and see the different programs.