Table 3.

Characteristics of included control studies

Year/author	Study design	Number of patients/hips (follow-up)		Average age (years)		Gender (M/F)		Initial AVN class (hips)		AVN etiology (patients/hips)		Follow-up time (years) /rate		Validity of the studies
		TIG	Other	TIG	Other	TIG	Other	TIG	Other	TIG	Other	TIG	Other
2016/Zhao/Chinaa [21]	RCT	23/23	25/25	30 ± 7	33 ± 8	14/9	15/10	ARCO: IIA (4)/IIB (5)/IIC (4)/IIIA (4)/IIIB (4)/IIIC (2)	ARCO: IIA (5)/IIB (5)/IIC (3) IIIA (5)/IIIB (4)/IIIC (3)	Steroid (7 patients)/alcohol (7)/others (9)	Steroid (9 patients)/alcohol (5)/others (11)	1/100%	1/100%	Additional file 1: Appendix 2
2006/Yen/Chinab [22]	Case-control	33/39	22/22	40 (26–63)	38 (28–52)	30/3	20/2	Steinberg: II (11)/III (12)/IV (16)	Steinberg: II (4)/III (11)/IV (7)	Steroid (1 patient)/alcohol (15)/idiopathic (17)	Steroid (1 patient)/alcohol (12)/idiopathic (9)	> 4/NA	> 3/NA	Additional file 1: Appendix 2
2003/Hasegawa/Japan+c [23]	Case-control	26/31	63/77	37.9 (25–53)	39 (19–64)	23/3	44/19	Ficat and Arlet: II (28)/III (3) JIC classification: IB (1)/IC (25)/II (4)/III (1)	Ficat and Arlet: II (34)/III (43) JIC classification: IB (3)/IC (62)/II (12)	Steroid (8 hips)/alcohol (16)/idiopathic (7)	Steroid (46 hips)/alcohol (24)/idiopathic (7)	13 (10–15)/3.84%	7 (5–11)/3.07%	Additional file 1: Appendix 2

TIG target intervention group, other other treatments as a control group for the target intervention group, NA not available

^aTIG refers to the Mg screw group (vascularized bone grafting fixed by Mg screws), and other treatments refer to vascularized bone grafting without fixation as a control group

^bTIG refers to vascularized iliac pedicle bone grafting, and other treatments refer to free vascularized fibula bone grafting

^cTIG refers to vascularized iliac pedicle bone grafting, and other treatments refer to transtrochanteric rotational osteotomy