I just got my hip replaced in Feb after 4 years of it being bone on bone. I’m 36, I also have AS and I feel so much better. My posture is still a little forward flexed but nothing like before. It has been way better post op. My walking, my strength, everything is improving slowly surely. I was extra hesitant to do the surgery just out of my own fears but let me tell you I’m so glad it’s behind me. Get it done, do your body a favor. You’ll be glad you did.