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Table 2 Characteristics of patients with surgical site infections following total hip or knee arthroplasty, 2013–2020

From: Development of machine learning models for the detection of surgical site infections following total hip and knee arthroplasty: a multicenter cohort study

Characteristic

Overall Cohort (n = 235)

Superficial SSIs (n = 77)

Deep SSIs (n = 57)

Organ space SSIs (n = 101)

p-value

Age (years), median (IQR)

66 (59–72)

64 (58–75)

67 (60–71)

65 (59–72)

0.879†

Male

129 (54.89)

34 (44.16)

37 (64.91)

58 (57.43)

0.046‡

Charlson comorbidity index

    

0.244‡

 0

195 (82.98)

65 (84.42)

48 (84.21)

82 (81.19)

 

 1

27 (11.49)

11 (14.29)

6 (10.53)

10 (9.90)

 

  > 2

13 (5.53)

1 (1.30)

3 (5.26)

9 (8.91)

 

Procedure type

    

0.021‡

 Knee implantation

138 (58.72)

54 (70.13)

34 (59.65)

50 (49.50)

 

 Hip implantation

97 (41.28)

23 (29.87)

23 (40.35)

51 (50.50)

 

Procedure lateral

    

0.595‡

 Left

118 (50.21)

37 (48.05)

32 (56.14)

49 (48.51)

 

 Right

111 (47.23)

37 (48.05)

25 (43.86)

49 (48.51)

 

 Bilateral

6 (2.55)

3 (3.90)

0

3 (2.97)

 

Blood culture type

    

 < .0001‡

 Superficial wound swab

22 (11.58)

19 (50.00)

2 (3.92)

1 (0.99)

 

 Deep wound

39 (20.53)

2 (5.26)

22 (43.14)

15 (14.85)

 

 Tissue

82 (43.16)

6 (15.79)

17 (33.33)

59 (58.42)

 

 Fluid aspirate

35 (18.42)

10 (26.32)

8 (15.69)

17 (16.83)

 

 Other

12 (6.32)

1 (2.63)

2 (3.92)

9 (8.91)

 

Blood culture result

    

 < .0001‡

 Positive

172 (73.19)

23 (29.87)

50 (87.72)

99 (98.02)

 

 Negative

18 (7.66)

15 (19.48)

1 (1.75)

2 (1.98)

 

 NA

45 (19.15)

39 (50.65)

6 (10.53)

0

 

Days from admission to procedure

0

0

0

0

–

Days from procedure to discharge

3 (2,5)

3 (3,4)

3 (2,5)

3 (2,5)

0.928†

Length of hospital stay, median, days

3 (2,5)

3 (3,4)

3 (2,5)

3 (2,5)

0.940†

Discharge disposition

    

0.138‡

 Home

221 (94.04)

72 (93.51)

51 (89.47)

98 (97.03)

 

 Transfer

10 (4.26)

4 (5.19)

3 (5.26)

3 (2.97)

 

 Death/long term care

0

0

0

0

 

Re-admission

201 (85.53)

45 (58.44)

57 (100.00)

99 (98.02)

 < .0001‡

  1. IQR interquartile range, SSIs surgical site infections
  2. †Wilcoxon rank-sum test;
  3. ‡Chi-square test