The incidence and risk factors for femoral head necrosis after femoral neck fracture in pediatric patients: a systematic review and meta-analysis

Table 2 Subgroup analysis of femoral head necrosis rate

Subgroups	No. of studies	No. of total fractures	Number of AVN	AVN incidence (%)	95% CI	I² (%)	P value	Model
Time
1962–1999	7	299	87	26	13–39	87.8	< 0.001	R
2000–2010	11	301	72	21	13–30	76.8
2011–2022	12	593	144	22	16–28	60.3
Country
Africa	2	74	27	36	25–47	0	< 0.001	R
Europe	4	134	44	26	8–44	82.4
North America	9	299	84	23	13–34	81.8
Asian	15	686	148	19	14–25	69.9
Sample size
≥ 39	10	759	209	28	22–34	73.7	< 0.001	R
< 39	20	435	95	19	13–25	69.5
Delbet grade
Delbet I	22	60	34	45	31–59	0	0.859	F
Delbet II	27	587	191	32	26–39	66.1	< 0.001	R
Delbet III	28	416	57	17	14–21	0	0.740	F
Delbet IV	23	103	5	12	2–22	0	0.987	F
Age
< 12 year	13	289	61	22	14–30	50.9	0.026	R
≥ 12 year	13	281	85	28	18–39	71.6	< 0.001	R

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