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 |