Table 4.
Subgroup analysis and respective results for sensitivity and specificity. PTC, peri-implant tissue culture; SFC, sonicate fluid culture
| Total (%) | Sensitivity | Specificity | ||||||
|---|---|---|---|---|---|---|---|---|
| SFC | PTC | p | SFC | PTC | p | |||
| Initial diagnosis | ||||||||
| Suspected infection (local signs) | 93 | 40.4 | 89.2 | 84.3 | .22 | 50.0 | 30.0 | .63 |
| Non-union | 68 | 29.6 | 92.3 | 76.9 | .63 | 78.2 | 90.9 | .12 |
| Implant dislocation | 47 | 20.4 | 100.0 | 90.9 | – | 80.6 | 88.9 | .51 |
| Peri-implant fracture | 8 | 3.5 | –a | – | – | 50.0 | 87.5 | .38 |
| Hardware irritation | 6 | 2.6 | – | – | – | 50.0 | 83.3 | .63 |
| Chronic osteitis | 5 | 2.2 | – | – | – | 60.0 | 100.0 | – |
| Posttraumatic osteoarthritis | 3 | 1.3 | – | – | – | 100.0 | 100.0 | – |
| Bone | ||||||||
| Femur | 93 | 40.4 | 93.1 | 89.7 | 1 | 76.6 | 93.8 | .013 |
| Lower leg | 71 | 30.9 | 90.4 | 82.7 | .13 | 73.7 | 78.9 | 1 |
| Humerus and shoulder girdle | 29 | 12.6 | 100.0 | 87.5 | – | 66.7 | 90.5 | .13 |
| Spine | 15 | 6.5 | 91.7 | 83.3 | 1 | 33.3 | 66.7 | 1 |
| Forearm | 9 | 3.9 | 100.0 | 100.0 | – | 87.5 | 100.0 | – |
| Pelvis | 8 | 3.5 | 100.0 | 100.0 | – | 60.0 | 60.0 | 1 |
| Foot | 5 | 2.2 | 0.0 | 0.0 | – | 66.7 | 66.7 | 1 |
| Fracture fixation device | ||||||||
| Plate and screws | 167 | 72.6 | 90.0 | 82.9 | .18 | 73.2 | 89.7 | .004 |
| Nail | 26 | 11.3 | 100.0 | 93.8 | – | 60.0 | 100.0 | – |
| Screws | 24 | 10.4 | 83.3 | 77.8 | 1 | 83.3 | 66.7 | 1 |
| Multiple | 9 | 3.9 | 100.0 | 100.0 | – | 82.2 | 71.4 | 1 |
| (Cerclage) wires | 4 | 1.7 | 100.0 | 100.0 | – | 66.7 | 100.0 | – |
| Early vs. delayed vs. lateb | ||||||||
| Early | 11 | 4.8 | 100.0 | 100.0 | – | 77.8 | 77.8 | 1 |
| Delayed | 71 | 30.9 | 86.4 | 77.3 | .22 | 59.3 | 92.6 | .004 |
| Late | 148 | 64.3 | 93.4 | 88.5 | .38 | 77.0 | 88.5 | .08 |
| Preoperative antibioticsc | ||||||||
| Yes | 35 | 15.2 | 85.2 | 70.4 | .22 | 62.5 | 50.0 | 1 |
| No | 195 | 84.8 | 92.5 | 88.8 | .38 | 73.9 | 91.3 | .001 |
| Sinus excludedd | 180 | 78.3 | 98.2 | 93.0 | .25 | 73.2 | 88.6 | .003 |
| 3+ tissue culturese | 88 | 38.3 | 86.0 | 79.1 | .45 | 75.6 | 82.2 | .61 |
| Sinus excluded AND 3+ tissue cultures | 66 | 28.7 | 100 | 90.5 | – | 75.6 | 82.2 | .61 |
a–, missing values/not calculable
bEarly: < 2 weeks after device implantation; delayed: 2–10 weeks; late: > 10 weeks
cAny administration of antibiotics within 14 days prior to surgery
dPatients with sinus tract and/or wound breakdown excluded from sub-analysis
ePatients with less than three retrieved corresponding tissue cultures excluded from sub-analysis