Definitely would mention that at your next dr. appt if you haven't already especially that you were stiffer than expected, and still participated in gymnastics which can be a form of PT, and could have slowed your progression some. It's a wonderful sport for staying active and limber, did it myself as a child, and I think that along with the host of other sports I played is what kept me upright when my back went out on me.

Slouching is a killer and something I failed to learn to do as a child. After the knees and ankles went remembering C O B, has saved me from numerous falls. In just wish I could find an definitive answer for you. Again though best of luck, i hope you can find answers soon