Retrospective Analysis of Infection Factors in Secondary Internal Fixation after External Fixation for Open Fracture of a Long Bone: A Cohort of 117 Patients in a Two-Center Clinical Study

Table 1

Univariate predictors for SSI of preoperative variables.

Variable	SSI ()	No SSI ()	Infection rates (%)	value
Age (years)
≤50 years	14 (82.4%)	87 (77.0%)	14/101 (13.9%)	0.762
>50 years	3 (17.6%)	26 (23.0%)	3/29 (10.3%)
Gender, number (%)
Male	15 (88.2%)	85 (75.2%)	15/100 (15%)	0.357
Female	2 (11.8%)	28 (24.8%)	2/30 (6.7%)
Injured area
Humerus	0	5 (4.4%)	0	0.416
Ulna and radius	1 (5.9%)	15 (13.3%)	1/16 (6.3%)
Femoral	4 (23.5%)	24 (21.2%)	4/28 (14.3%)
Tibia and fibula	12 (70.6%)	69 (61.1%)	12/81 (14.8%)
Multiple trauma
+	15 (88.2%)	78 (69.0%)	15/93 (16.1%)	0.149
-	2 (11.8%)	35 (31.0%)	2/37 (5.4%)
Type of open fracture (Gustilo classification)
I or II	2 (11.8%)	46 (40.7%)	2/48 (4.2%)	0.001^a
IIIA	3 (17.7%)	36 (31.9%)	3/39 (7.7%)
IIIB	6 (35.3%)	23 (20.4%)	6/29 (20.7%)
IIIC	6 (35.3%)	8 (7.1%)	6/14 (42.8%)
AO type
A	3 (17.6%)	39 (34.5%)	3/42 (7.1%)	0.416
B	6 (35.3%)	32 (28.3%)	6/38 (15.8%)
C	8 (47.1%)	42 (37.2%)	8/50 (16.0%)
Degree of soft tissue damage
Mild	10 (58.8%)	69 (61.1%)	10/79 (12.7%)	0.176
Moderate	1 (5.9%)	23 (20.3%)	1/24 (4.2%)
Severe	6 (35.3%)	21 (18.6%)	6/27 (22.2%)
Debridement time
≤6 h	5 (29.4%)	26 (23.0%)	5/31 (16.1%)	0.296
>6 h	12 (70.6%)	87 (77.0%)	12/99 (12.1%)
Duration of external fixation
≤14 d	4 (23.5%)	58 (51.3%)	4/62 (6.5%)	0.031^a
14-28 d	2 (11.8%)	19 (16.8%)	2/21 (9.5%)
≥28 d	11 (64.7%)	36 (31.9%)	11/47 (23.4%)
Pin-site infection
+	4 (23.5%)	8 (7.1%)	4/12 (33.3%)	0.052
-	13 (76.5%)	105 (92.9%)	13/118 (11.0%)
WBC (/L)
/L	10 (58.8%)	94 (83.2%)	10/104 (9.6%)	0.044^a
/L	7 (41.2%)	19 (16.8%)	7/26 (26.9%)
(/L)
/L	15 (88.2%)	92 (81.4%)	15/107 (14.0%)	0.736
/L	2 (11.8%)	21 (18.6%)	2/23 (8.7%)
CRP (0-6 mg/L)
≤6 mg/L	3 (17.6%)	41 (36.3%)	3/44 (6.8%)	0.012^a
>6 mg/L	14 (82.4%)	72 (63.7%)	14/86 (16.3%)
ESR (male 0-15 mm/h, female 0-20 mm/h)
≤15/20 mm/h	2 (11.8%)	41 (36.3%)	2/43 (4.7%)	0.031^a
>15/20 mm/h	15 (88.2%)	72 (63.7%)	15/87 (17.2%)
Fasting plasma glucose (3.9-6.1 mmol/L)
3.9-6.1 mmol/L	15 (88.2%)	94 (83.2%)	15/109 (13.8%)	0.862
>6.1 mmol/L	2 (11.8%)	19 (16.8%)	2/21 (9.5%)
ALB (35-55 g/L)
<35 g/L	9 (52.9%)	27 (23.9%)	9/36 (25.0%)	0.019^a
35-55 g/L	8 (47.1%)	86 (76.1%)	8/94 (8.5%)

^a denotes significance.