Table 2.

Acetabular anatomy and morphological parameters for Crowe Iva, IVb DDH and control group

	Control group	DDH group
		IVa (n = 27)	IVb (n = 26)	P valure
Dislocation rate, % (SD; range)	/	30.04 (3.71; 21.60 to 37.87)	25.08 (5.17; 19.63 to 38.38)	t=-4.019; P < 0.001**
Acetabular Length, mm (SD; range)	54.50 (2.02; 51.37 to 59.12)	38.70 (4.57; 30.53 to 46.62) ##	39.63 (3.97; 34.98 to 50.65) ##	t = 0.789; P = 0.434
Acetabular Height, mm (SD; range)	34.37 (3.08; 28.20 to 42.40)	28.53 (4.22; 19.41 to 38.27) ##	30.06 (4.15; 21.30 to 38.25) ##	t = 1.332; P = 0.189
Acetabular Width, mm (SD; range)	50.09 (2.95; 42.27 to 55.41)	27.27 (6.84; 18.02 to 41.62) ##	28.12 (6.60; 15.38 to 45.39) ##	t = 0.463; P = 0.645
Acetabular Depth, mm (SD; range)	27.27 (2.62; 23.89 to 33.30)	13.35 (3.37; 7.52 to 21.72) ##	14.44 (3.15; 7.51 to 21.90) ##	t = 1.212; P = 0.231
Acetabular Volume, mm3 (SD; range)	37234.31 (7395.23; 29995.27 to 48034.93)	6934.87 (2148.18; 5002.00 to 12270.37) ##	8221.78 (2106.68; 5066.66 to 13757.24) ##	t = 1.684; P = 0.103
Cup Size, mm (SD; range)	52.65 (2.41; 50 to 58)	44.22 (0.85; 44 to 48) ##	44.15 (0.54; 44 to 46) ##	t = 0.348; P = 0.729
Cup-CE, deg (SD; range)	45.74 (5.58; 31.74 to 55.69)	24.74 (7.08; 12.93 to 40.13) ##	20.70 (7.59; 8.20 to 38.71) ##	t=-2.007; P = 0.050*
Cup-Sharp, deg (SD; range)	35.93 (4.16; 27.39 to 46.84)	47.43 (4.00; 40.93 to 56.12) ##	51.20 (6.05; 34.95 to 62.79) ##	t = 2.688; P = 0.010*
Anteversion Angle, deg (SD; range)	20.07 (7.24; 7.13 to 37.68)	30.17 (9.06; 11.41 to 50.14) ##	36.49 (5.37; 27.74 to 49.48) ##	t = 3.075; P = 0.003**
Medial Thickness, mm (SD; range)	3.63 (1.24; 2.21 to 6.66)	7.21 (3.21; 2.57 to 14.31) ##	6.13 (2.40; 2.53 to 10.93) ##	t=-1.382; P = 0.173

IVa: without false acetabulum; IVb: with false acetabulum;

^#p < 0.05, ^##p < 0.01, compared with the control group; *p < 0.05, ** p < 0.01, for the comparison between the type IVa DDH and type IVb DDH