Outcomes of autologous bone grafts vs bone substitutes in tibial plateau fractures: A meta-analysis

Table 1 Included study characteristics with subgroup classifications

Ref.	Year	Country	Region	Sample size (BS/AG)	Mean age (BS/AG)	Gender ratio (M:F)	Fracture classification	Fracture complexity	Study quality
Pernaa et al[12], 2011	2011	Finland	Western	5/10	52/58	7:8	Not reported	Unknown	B
Jónsson et al[13], 2015	2015	Sweden	Western	11/9	48.7/49.4	9:11	Schatzker II-III	Simple	B
Heikkilä et al[14], 2011	2011	Finland	Western	14/11	57/50	12:13	AO 41-B2, 41-B3	Complex	A
Russell et al[15], 2008	2008	United States	Western	82/38	43/43	73:46	Schatzker I-VI	Mixed	B
Hofmann et al[8], 2020	2020	Germany	Western	65/68	47.0/46.3	58:75	AO 41-B2, 41-B3, other	Complex	A
An et al[16], 2021	2021	China	Asian	37/37	46.18/48.02	53:21	Schatzker II-VI	Mixed	A
Chen AF et al[17], 2020	2020	China	Asian	20/18	40.3/44.2	18:20	Not reported	Unknown	A

BS: Bone substitute; AG: Autologous bone graft; M:F: Male:Female ratio.

Table 2 Fracture pattern analysis results

Fracture complexity	Autologous bone graft		Bone substitute		Effect size (95%CI)	P value
	n	Mean (SD)	n	Mean (SD)
Joint depression (mm)
Simple fractures	9	1.49 (1.05)	11	1.30 (1.22)	MD = 0.19 (-0.81, 1.19)	0.70
Complex fractures	11	2.00 (3.00)	14	2.00 (2.00)	MD = 0.00 (-2.06, 2.06)	1.00
Unknown complexity	10	1.60 (1.85)	5	1.40 (0.80)	MD = 0.20 (-1.14, 1.54)	0.77
Secondary collapse
Simple fractures	37	5 (13.5%)	37	5 (13.5%)	RR = 1.00 (0.32, 3.17)	1.00
Complex fractures	64	43 (67.2%)	58	37 (63.8%)	RR = 1.05 (0.81, 1.36)	0.70
Mixed complexity	70	15 (21.4%)	103	15 (14.6%)	RR = 1.47 (0.77, 2.81)	0.24

MD: Mean difference; RR: Risk ratio.

Table 3 Geographic and demographic subgroup analyses, n (%)

Subgroup	Autologous bone graft		Bone substitute		Effect size (95%CI)	P value	Subgroup difference (P value)
	n	Mean/Events	n	Mean/Events
Joint depression (mm)
Western	30	Various	30	Various	MD = 0.17 (-0.58, 0.91)	0.66	N/A
Asian	-	-	-	-	-	-
Secondary collapse
Western	134	63 (47.0)	161	48 (29.8)	RR = 1.45 (1.07, 1.97)	0.02	0.09
Asian	37	5 (13.5)	37	9 (24.3)	RR = 0.56 (0.21, 1.50)	0.25
Operative time (minute)
Western	62	112.0 (42.0)	62	104.0 (36.0)	MD = 8.00 (-5.77, 21.77)	0.25	0.04
Asian	55	110.9 (17.1)	57	87.2 (15.5)	MD = 23.65 (17.63, 29.68)	< 0.001
Blood loss (mL)
Western	73	244.0 (248.7)	76	127.6 (152.9)	MD = 89.97 (42.28, 137.66)	< 0.001	0.48
Asian	18	190.3 (15.6)	20	120.5 (12.3)	MD = 69.80 (60.80, 78.80)	< 0.001
Infection rate
Western	99	2 (2.0%)	147	3 (2.0%)	RR = 0.99 (0.17, 5.82)	0.99	N/A

MD: Mean difference; RR: Risk ratio; N/A: Not applicable (insufficient data for comparison).

Table 4 Methodological factors impact analysis

Factor	Subgroup	Joint depression	Secondary collapse	Operative time	Blood loss
Publication period	2008-2015	MD = 0.17 (-0.58, 0.91)	RR = 2.01 (0.98, 4.11)	-	MD = 200.00 (-94.29, 494.29)
	2016-2021	-	RR = 0.98 (0.73, 1.31)	MD = 21.14 (15.62, 26.66)	MD = 70.38 (61.53, 79.22)
	P value for difference	N/A	0.08	N/A	0.17
Study quality	A-rated	MD = 0.00 (-2.06, 2.06)	RR = 0.98 (0.73, 1.31)	MD = 21.14 (15.62, 26.66)	MD = 70.49 (61.65, 79.34)
	B-rated	MD = 0.19 (-0.61, 0.99)	RR = 2.01 (0.98, 4.11)	-	-
	P value for difference	0.87	0.08	N/A	N/A
Sample size	< 50 participants	MD = 0.19 (-0.61, 0.99)	RR = 1.00 (0.32, 3.17)	MD = 19.80 (9.59, 30.01)	MD = 106.69 (47.74, 165.64)
	≥ 50 participants	MD = 0.00 (-2.06, 2.06)	RR = 1.10 (0.82, 1.48)	MD = 21.50 (14.90, 28.10)	MD = 87.00 (29.33, 144.67)
	P value for difference	0.87	0.91	0.79	0.62

Number of studies for each outcome in the order: Joint Depression/Secondary Collapse/Operative Time/Blood Loss; MD: Mean difference (autograft - bone substitute); RR: Risk ratio; All effect sizes shown with 95% Confidence Intervals; N/A: Not applicable (insufficient data for comparison).