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Table 1 Demographics, clinical characteristics and outcomes between culture-proven non-mycobacterial and rapidly growing mycobacterial (RGM) prosthetic joint infection

From: Rapidly-growing mycobacterial infection: a recognized cause of early-onset prosthetic joint infection

  Culture-proven non-mycobacterial
PJI (n = 111)
RGM PJI
(n = 11)
P value
Age, mean ± SD (yrs) 63.5 ± 13.7 66.27 ± 9.5 .505
Gender, no. (%)
 Male 40 (36) 3 (27.3) .745
 Female 71 (64) 8 (72.7)  
BW (kg), mean ± SD 64.3 ± 11.7 58.3 ± 9.9 .104
BMI (kg/m2), mean ± SD 25.6 ± 4.2 25.2 ± 4.0 .798
BMI ≥25, no. (%) 27/57 (47.4) 5/8 (62.5) .475
Site of PJI, no. (%)
 Knee 67 (60.4) 10 (90.9) .053
 Hip 44 (39.6) 1 (9.1)  
Prior joint disease, no. (%)
 Primary degenerative 64 (57.7) 9 (81.8) .197
 Secondary degenerativea 47 (42.3) 2 (18.2)  
Comorbidity, no. (%)
 Diabetes mellitus 25 (22.5) 2 (18.2) 1.0
 Chronic kidney disease 12 (10.8) 1 (9.1) 1.0
 Chronic lung disease 2 (1.8) 0(0) 1.0
 Chronic liver disease 6 (5.4) 0 (0) 1.0
 Cardiovascular disease 54 (48.6) 4 (36.4) .436
 Malignancy 4 (3.6) 0 (0) 1.0
Immnunosuppressive 3 (2.7) 0 (0) 1.0
No immnunosuppressive 108 (97.3) 11 (100)  
Rheumatologic disease 4 (3.6) 0 (0) 1.0
Duration, median (min, max) (days)b 330 (4, 10,220) 60 (19, 2675) .001
Onset, no. (%)
  ≤ 90 days 19 (17.1) 9 (81.8) < .001
  > 90 days 92 (82.9) 2 (18.2)  
Clinical presentations, no. (%) 110 (99.1) 11 (100) 1.0
 Pain 99 (89.2) 10 (90.9) 1.0
 Loosening 26 (23.4) 0 (0) .118
 Sinus drainage 41 (36.9) 6 (54.5) .333
 Fever 34 (30.6) 2 (18.2) .504
Radiological loosening 36/55 (65.5) 1/6 (16.7) .031
Peripheral WBC count, median (min, max) (cell/mm3)
Log WBC count, mean ± SD
8270 (3020, 42,500)
9.1 ± 0.4
7220 (6320, 14,430)
9.0 ± 0.2
.066
.215
Cr, median (min, max) (mg/L) 0.8 (0.2, 4.4) 0.8 (0.3, 1.6) .634
ESR, mean ± SD (mm/h) 89.6 ± 29.9 92.6 ± 29.7 .758
CRP, median (min, max) (mg/L) 46.3 (3, 401) 50.9 (3, 117) .733
Synovial fluid WBC, median (min, max) (cell/mm3) 37,700 (3050, 300,800) 1100 (1100, 1100) .109
Periprosthetic tissue cultures, no. (%)
 Single isolate growth 87 (80.6) 11 (100) .560
  ≥ 2 isolate growth 12 (11.1) 0 (0)  
 No growth 9 (8.3) 0 (0)  
Initial ATB therapy, no. (%)
 Appropriate 52 (47.7) 0 (0) .005
 Inappropriate 57 (52.3) 11 (100)  
 Duration, median (min, max) (days) 47 (6, 270) 42 (14, 129) .272
Maintenance oral ATB therapy, no. (%)
 Single 62 (75.6) 0 (0) < 0.001
 Combined 20 (24.4) 11 (100)  
 Duration, median (min, max) (days) 134 (14, 605) 365 (60, 910) .025
Surgical treatment, no. (%)
 Retention of prosthesis 19 (17.8) 1 (9.1) .688
 Removal of prosthesis 88 (82.2) 10 (90.9)  
Outcomes at 6 months, no. (%)
 Favorable 69 (79.3) 6 (66.7) .405
 Unfavorable 18 (20.7) 3 (33.3)  
Outcomes at 12 months, no. (%)
 Favorable 58 (77.3) 5 (83.3) 1.0
 Unfavorable 17 (22.7) 1 (16.7)  
  1. Abbreviations: ATB antibiotics, BMI body mass index, BW body weight, Cr creatinine, CRP Creactive protein, ESR erythrocyte sedimentation rate, PJI prosthetic joint infection, SD standard deviation, WBC white blood cell
  2. aIncluding prior surgery, previous fracture, avascular necrosis, rheumatoid arthritis, post infection, gout and tumor
  3. bTemporal duration from prosthesis implantation to clinical diagnosis of PJI