Efficacy of the femoral neck system in femoral neck fracture treatment in adults: A systematic review and meta-analysis

Table 1 Characteristics of the studies analyzed in the current meta-analysis

Complications		A; B; C; D; E	A; B; C; F; G	A; B; D; E	A; B; E	B; I
Outcomes		Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up	Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up	Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up	Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up	Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up
Type of fracture		Garden II/III/IV	Pauwels I/II/III	Garden II/III/IV	Garden II/III/IV	Garden I/II/III/IV
Study type		Retrospective study	Retrospective study	Retrospective study	Retrospective study	Retrospective study
Follow-up time		≥ 6 mo	5-18 mo	≥ 12 mo	3-18 mo	Unknown
G2		CCS	CCS	CCS	CCS	CCS
G1		FNS	FNS	FNS	FNS	FNS
Participants (n, age: mean ± SD)	G2	38, 48.8 ± 10.1	47, 43.7 ± 13.1	57, 53.2 ± 11.3	58, 49	19, 41.2
(n, age: mean ± SD)	G1	32, 49.4 ± 11.0	47, 47.8 ± 9.8	62, 54.0 ± 13.0	24, 52	15, 42.0
First author, year		Ren C (2021) [11]	Yang J (2021) [12]	Xiong W (2021) [13]	Yan C (2021) [14]	Yang Y (2021) [15]
Complications		A; B; E; H	A; D; E	B; E; H; I	A; B; E; D	B
Outcomes		Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up	Operation time; intraoperative blood loss; HHS at the last follow-up	Operation time; fracture healing time; HHS at the last follow-up	Operation time; intraoperative blood loss; fracture healing time; HHS at the last follow-up	Operation time
Type of fracture		Pauwels I/II/III	Pauwels III	Garden I/II/III/IV	Pauwels I/II/III	Garden I/II
Study type		Retrospective study	Retrospective study	Retrospective study	Retrospective study	Retrospective study
Follow-up time		≥ 6 mo	10-22 mo	12-24 mo	14-24 mo	3-6 mo
G2		CCS	CCS	CCS	CCS	CCS
G1		FNS	FNS	FNS	FNS	FNS
Participants (n, age: mean ± SD)	G2	24, 50.46 ± 9.26	30, 53.14 ± 7.19	36, 47.58 ± 10.31	45, 54.8 ± 11.7	32, 85 ± 6.6
(n, age: mean ± SD)	G1	20, 50.45 ± 8.45	30, 54.53 ± 6.71	33, 50.61 ± 10.30	47, 57.4 ± 15.0	15, 86.1 ± 4.6
First author (year)		Hu H (2021) [16]	Zhou X (2021) [17]	He C (2021) [18]	Tang Y (2021) [19]	Vazquez O (2021) [20]

G1: Treatment group; G2: Control group; HHS: Harris Hip score; A: Avascular necrosis of the femoral head; B: Femoral neck shortening; C: Deep venous thrombosis; D: Loosening of screws; E: Delayed union or nonunion; F: Thigh irritation; G: Postoperative infection; H: Screw penetration; I: Screw back-off.

Table 2 Other complications reported in the analyzed studies

Complications	Number of cases (FNS/other implants)	OR (95%CI)	P	I2 (%)
Deep venous thrombosis	3/5	0.64 (0.15, 2.78)	0.55	0
Thigh irritation	0/15	0.02 (0.00, 0.38)	/	/

FNS: Femoral Neck System; OR: Odds ratio; CI: Confidence interval.