Table 1.

Demographic data

	Control group	DDH group
		IVa (n = 27)	IVb (n = 26)	P valure
Males/females (no.)	6/40	3/24	3/23	χ2 = 0.002, P = 0.961
Age, years (SD; range)	45.2 (13.96; 20 to 72)	38.78 (14.78; 20 to 70)	43.69 (12.24; 23 to 65)	t = 1.316; P = 0.194
Height, cm (SD; range)	162.85 (7.25; 155 to 185)	157.74 (10.30; 141 to 175)	156.08 (9.10; 143 to 175)	t=-0.622; P = 0.536
BMI, kg/m2 (SD; range)	24.02 (2.94; 18.00 to 35.42)	23.78 (3.96; 18.73 to 30.08)	22.68(5.05 13.33 to 35.42)	t=-0.891; P = 0.377

^#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