Have I ruptured my abdominoplasty stitches?

Did you fell a 'pop'? frankly you will not be able to tell on your own whether one of your stitches has ruptured. Let your doc know what happened so he can examine your abdomen at your next post-op appointment. Likely you are getting concerned over nothing. The sutures for an abdominoplasty are pretty strong. Especially the ones of most concern that are used to pull together your abdominal muscles. In the unlikely event that one of these pulls loose, a small incision can be made to repair the suture.