Skip to main content

Table 2 Diagnostic performance of radiological and non-radiological findings for the diagnosis of infection (overall cohort)

From: The value of conventional radiographs for diagnosing internal fixation-associated infection

Variable Aseptic cases (n [total, %])a Septic cases (n [total,%])a Sensitivity
(%, 95 CI)
Specificity
(%, 95 CI)
PPV
(%, 95 CI)
NPV
(%, 95 CI)
Accuracy
(%, 95 CI)
PLR NLR DOR (95% CI) p value
Radiological findings
 Radiolucent line 29 (of 305 cases, 9.5) 19 (of 116 cases, 16.4) 16.4 (10.2–24.4) 90.5 (86.6–93.5) 39.6 (27.7–52.9) 74.0 (72.3–75.7) 70.1 (65.5–74.4) 1.72 (1.01–2.95) 0.92 (0.85–1.01) 1.86 (1.00–3.48) 0.047
 Implant breakage 43 (305 cases, 14.1) 9 (116 cases, 7.8) 7.8 (3.6–14.2) 85.9 (81.5–89.6) 17.3 (9.5–29.4) 71.0 (69.6–72.4) 64.3 (59.6–69.0) 0.55 (0.28–1.09) 1.07 (1.00–1.15) 0.51 (0.24–1.09) 0.077
 Implant displacement 32 (305 cases, 10.5) 13 (116 cases, 11.2) 11.2 (6.1–18.4) 89.5 (85.5–92.7) 28.9 (18.11 42.7) 72.6 (71.1–74.1) 67.9 (63.2–72.4) 1.07 (0.58–19.6) 0.99 (0.92–1.07) 1.08 (0.54–2.13) 0.832
 Periosteal reaction 16 (305 cases, 5.2) 14 (116 cases, 12.1) 12.1 (6.8–19.4) 94.8 (91.6–97.0) 46.7
(30.6–63.4)
73.9 (72.5–75.3) 71.9 (67.4–76.2) 2.30 (1.16–4.56) 0.93 (0.86–1.00) 2.48 (1.17–5.26) 0.015
Non-radiological findings
 Increased WBC countb 16 (193 cases, 8.3) 21 (93 cases, 22.6) 22.6 (14.6–32.4) 91.7 (86.3–95.5) 56.8 (41.8–70.6) 71.1 (68.6–73.4) 69.2 (63.5–74.5) 2.72 (1.49–4.97) 0.84 (0.75–0.95) 3.2 (1.6–6.5) 0.001
 Increased CRP valuec 32 (193 cases, 16.6) 41 (93 cases, 44.1) 44.1 (33.8–54.8) 83.4 (77.4–88.4) 56.2 (46.4–65.4) 75.6 (71.9–78.9) 70.6 (65.0–75.8) 2.66 (1.80–3.93) 0.67 (0.55–0.81) 3.97 (2.27–7.69) <  0.0001
 Positive tissue cultures 37 (239 cases, 15.5) 94 (111 cases, 84.7) 84.7 (76.6–90.8) 84.5 (79.3–88.7) 71.8 (65.2–77.5) 92.2 (88.4–94.7) 84.6 (80.4–88.2) 5.47 (4.03–7.43) 0.18 (0.12–0.28) 30.19 (16.17–56.36) <  0.0001
 Positive sonication culture 89 (305 cases, 29.2) 107 (116 cases,92.2) 92.2 (85.8–96.4) 70.8 (65.4–75.9) 54.6 (50.0–59.1) 96.0 (92.7–97.8) 76.7 (72.4–80.7) 3.16 (2.63–3.79) 0.11 (0.06–0.21) 28.9 (14.0–59.5) <  0.0001
 Combined microbiologyd 0 112 (116 cases, 96.6) 96.6 (91.4–99.1) 99.3 (97.7–99.9) 100.0 98.7 (96.7–99.5) 99.1 (97.6–99.7) 0.03 (0.01–0.09) 15,275.0 (815.8–286,001.6) <  0.0001
  1. NOTE. PPV Positive predictive value, NPV Negative predictive value, PLR Positive likelihood ratio, NLR Negative likelihood ratio, DOR Diagnostic odds ratio
  2. (a) The denominator of total cases for each comparison is given in parentheses
  3. (b) White blood cell (WBC) count ≥11.000/ mm3
  4. (c) C-reactive protein (CRP) value ≥10 mg/l
  5. (d) Combination of sonication and tissue cultures