By the time the damage shows up on an x-ray, you have been in pain for years and have lost the time that you could have prevented some of the damage. If AS is treated early on, there can be less damage, or it can be postponed for many years. I had pain starting in my elbow at age 19 but I didn't get a Dx until I had severe damage and an x-ray led to the Dx at age 69. I suffered, on and off, for 50 years. So much of my pain could have been prevented.
Donna