Figure 1

Standing posterior-anterior radiographs of a patient with a type 6 curve. The patient's postoperative transverse plane pelvic rotation (TPPR) increase resolved: preoperative (Fig. 1-A), postoperative (Fig. 1-B), and at 2 years, 7 months postoperative (Fig. 1-C). The method of measuring the left/right hemipelvis ratio, which directly relates transverse plane pelvis rotation, is illustrated. The landmarks are the inferior ilium at the sacroiliac joint medially and the anterior superior iliac spine laterally. The horizontal distance between these 2 points on each hemipelvis is expressed as a left/right hemipelvis ratio.