Preoperative and follow-up body height, instrumented segment vertical height measurements, and apical vertebral body squaring.
| Variable | Skeletally Immature (Risser 0 to 2) | Skeletally Mature (Risser 3 to 5) | P Value |
| Body height, cm, median (range) | |||
| Preoperative | 156 (138–177) | 169 (159–180) | <0.001 |
| 2-y follow-up | 162 (153–178) | 175 (162–184) | 0.04 |
| Height gain | 8 (2–15) | 3.5 (0–15) | 0.04 |
| Upper and lower instrumented levels vertical height, cm, median (range) | |||
| Preoperative | 15 (13–20) | 20 (14–25) | <0.001 |
| First erect | 18 (13–20)a | 21 (15–26) | <0.001 |
| 2-y follow-up | 19.5 (14–24)a,b | 22 (16–26) | 0.12 |
| First erect gain | 1.5 (0–4) | 1 (0–3) | 0.15 |
| Total gain | 3.5 (1–8) | 1.5 (0–4) | <0.001 |
| Proportional height gain, % | 41.5 (20–71) | 33 (0–67) | 0.15 |
| Apical vertebral body squaring, degree, median (range) | |||
| First erect wedge | 9 (7–15) | 8 (5–13) | 0.13 |
| 2-y follow-up wedge | 3 (0–12)a | 6 (2–12)a | 0.02 |
| Follow-up squaring | 6 (3–8) | 1 (0–6) | <0.001 |