The idea is that your tendons in your back and abdomen, which hold you hips in place front to back, change which rotates the hip forward. No one is claiming bone change.
I think it does change and I noticed things changing around 6 months or so. I run and it changed my gait slightly.
However, I cannot find any hard evidence if i happens or not. There is a wiki article that says it does, and lots of people saying it, but nothing medical to back it up.