Table 2.

Subgroup comparison of clinical parameters

Variable	Group 1 (Postop TK ≥ 20°)	Group 2 (Postop TK<20°)	P value
Gender (female/male)	13/4	32/8	0.765
Age at surgery (year)	14.41 ± 1.50	14.38 ± 1.96	0.945
Rod diameter (5.5 mm/6.0 mm)	4/13	15/25	0.306
Rod material (Ti/CoCr)	7/10	28/12	0.041
Fused levels	12.18 ± 1.33	11.38 ± 1.69	0.088
Total screw number	18.06 ± 3.82	16.43 ± 3.53	0.124
Screw number of concave side	10.35 ± 1.73	9.15 ± 1.90	0.029
Screw number of convex side	7.71 ± 2.37	7.28 ± 2.03	0.488
Total screw density	1.49 ± 0.28	1.45 ± 0.25	0.637
Screw density of concave side	0.85 ± 0.13	0.81 ± 0.14	0.279
Screw density of convex side	0.63 ± 0.18	0.64 ± 0.15	0.854

Values are mean ± standard deviation, number of participants, or as otherwise indicated

Ti indicates titanium, CoCr cobalt chromium