Table: Baseline characteristics. Data are shown as number (percentage), median [range] or mean [standard deviation]

Factor	Total		Union		Nonunion
	(n = 62)		(n = 50)		(n = 12)		p-value
Sex, male	46	(74)	38	(76)	8	(67)	0.5
Age	32	[16–85]	30	[16–85]	40	[11.7]	0.2
Injury Severity Score	25	[17–48]	26	[17–48]	24	[4.9]	0.3
New Injury Severity Score	27	[17–50]	27	[17–50]	28	[6.2]	0.6
Femur fracture localization
Shaft	43	(69)	36	(72)	7	(58)	0.5
Distal	19	(31)	14	(28)	5	(42)	0.5
Type of femur fractures (AO):
Simple extra-articular	27	(44)	29	(60)	6	(50)	0.8
Complex extra-articular	21	(34)	10	(20)	3	(25)	0.7
Intra-articular	14	(23)	11	(22)	3	(25)	1.0
Soft tissue injury (Gustilo)
0: closed fracture	35	(57)	29	(58)	6	(50)	0.5
1: wound <1cm	8	(13)	5	(10)	3	(25)	0.2
2: wound >1 cm	6	(10)	5	(10)	1	(8)	1.0
3a: adequate soft tissue cover	4	(7)	3	(6)	1	(8)	1
3b: inadequate soft tissue cover	2	(3)	2	(4)	0		1
3c: associated arterial injury	0		0		0
Unknown	7	(11)	6	(12)	1	(8)
Type of fixation
External fixation + IMN	6	(10)	5	(10)	1	(8)	1
External fixation + plates	9	(15)	7	(14)	2	(17)	1
External fixation + screws	1	(2)	1	(2)	0		1
IMN	35	(57)	30	(60)	5	(42)	0.4
Plates	10	(16)	6	(12)	4	(33)	0.1
Screws	1	(2)	1	(2)	0		1
Number of surgical procedures	3	[1–18]	3	[1–13]	3	[1–18]	0.4
Inflammatory complications
Urinary tract infection	6	(10)	5	(10)	1	(8)	1
Surgical site infection	3	(5)	2	(4)	1	(8)	0.5
Pneumonia	10	(16)	9	(18)	1	(8)	0.7
MODS	3	(5)	2	(4)	1	(8)	0.5
Nonunion	13	(21)
Atrophic	11	(18)			11	(92)
Hypertrophic	1	(2)			1	(8)
Infected nonunion	2	(3)			2	(17)
ICU stay (days)	2	[0–68]	2	[0–46]	0	[0–68]	0.2
Hospital stay (days)	20	[4–154]	20	[4–95]	16	[4–154]	0.3

Baseline variables of patients with nonunion are compared with baseline variables of patients with union with the use of Fisher’s exact test or Mann-Whitney U test as indicated. IMN = intramedullary nailing, ICU = intensive care unit, MODS = multiple organ dysfunction syndrome.