Background
Methods
Patients
Influencing parameters
(Independent variables) | • Patient parameters:
sex, age, co-morbidities, metabolic diseases (kidney diseases, liver diseases, diabetes mellitus) • Infection parameters:
initial C-reactive protein (CRP), maximum CRP, discharge CRP (≤ 20 mg/l blood versus >20 mg/l)a, time of infection, extent of infection (superficial/deep), time point of infection (early [detected up to 4 weeks after surgery] or late onset [detected more than four weeks after surgery]), soft-tissue damage (according to the Tscherne and Oestern classification) • Germal parameters:
bacterial mixture, identification of bacteria, change in microbial strain during treatment, gram stain, bacterial metabolism (aerobic/anaerobic), bacterial load (Group 1 – very high contamination, Group 2- numerous bacteria, Group 3-isolated bacteria, Group 4-bacteria detectable after enhancement) • Treatment parameters:
Intensive care unit-stay, number of lavages until eradication, re-infection |
Outcome parameters (Dependent variables) | • cure of infection • type of wound closure • preservation or survival of the implant |
Treatment protocol
Statistics
Variable | Description | Cure of infectiona
|
p-valueb
| |||||
---|---|---|---|---|---|---|---|---|
Yes | No | |||||||
n
| mean or % | SD |
n
| mean or % | SD | |||
Gender | Male | 56 | 72.7 | 21 | 72.4 | 0.9743 | ||
Female | 21 | 27.3 | 8 | 27.6 | ||||
Age | 77 | 53.2 | 18.9 | 29 | 55.8 | 17.9 | 0.5588 | |
Stay at ICU | days | 77 | 3.0 | 5.2 | 29 | 5.6 | 7.3 | 0.0790 |
Initial procedure | Open | 1 | 1.3 | 2 | 6.9 | 0.1810 | ||
Closed | 76 | 98.7 | 27 | 93.1 | ||||
Tissue damage | Open Grade 0-2 | 11 | 14.3 | 8 | 27.6 | 0.0437 | ||
Open Grade 3-4 | 7 | 9.1 | 6 | 20.7 | ||||
Closed | 59 | 76.6 | 15 | 51.8 | ||||
Identification of a | Yes | 66 | 85.7 | 26 | 89.7 | 0.7535 | ||
microbial strain | No | 11 | 14.3 | 3 | 10.3 | |||
Presence of a bacterial mixture | Yes | 12 | 15.6 | 9 | 31.0 | 0.2016 | ||
No | 54 | 70.1 | 17 | 58.6 | ||||
No detectable germ | 11 | 14.3 | 3 | 10.3 | ||||
Change in microbial strain | Yes | 65 | 84.4 | 17 | 58.6 | 0.0047 | ||
No | 12 | 15.6 | 12 | 41.4 | ||||
Gram stain | Positive | 57 | 74.0 | 17 | 58.6 | 0.0746 | ||
Negative | 9 | 11.7 | 9 | 31.0 | ||||
No detectable germ | 11 | 14.3 | 3 | 10.4 | ||||
Bacterial metabolism | Aerobic | 3 | 3.8 | 4 | 13.8 | 0.0309 | ||
Anaerobic | 1 | 1.3 | 2 | 6.9 | ||||
Facultative anaerobic | 60 | 77.9 | 16 | 55.2 | ||||
Facultative aerobic | 2 | 2.6 | 3 | 10.3 | ||||
No detectable germ | 11 | 14.3 | 4 | 13.8 | ||||
Bacterial load | Plentiful | 18 | 23.4 | 9 | 31.0 | 0.9095 | ||
Numerous | 25 | 32.5 | 7 | 24.1 | ||||
Sporadic | 20 | 26.0 | 8 | 27.6 | ||||
Enrichment | 3 | 3.9 | 1 | 3.4 | ||||
No detectable germ | 11 | 14.3 | 4 | 13.8 | ||||
Number of lavages until eradication | sponge changes 0 | 33 | 42.9 | 18 | 62.1 | 0.0431 | ||
sponge changes 1 | 20 | 26.0 | 6 | 20.7 | ||||
sponge changes 2 | 14 | 18.2 | 0 | 0.0 | ||||
sponge changes ≥3 times | 8 | 10.4 | 3 | 10.3 | ||||
Never be eradicated | 2 | 2.6 | 2 | 6.9 | ||||
CRP Initial | [mg/l] | 72 | 78.2 | 92.1 | 25 | 69.6 | 78.4 | 0.8112 |
CRP Maximum | [mg/l] | 76 | 128.8 | 101.7 | 25 | 137.5 | 94.6 | 0.4547 |
CRP Discharge | [mg/l] | 75 | 16.3 | 23.6 | 26 | 46.1 | 52.1 | 0.0077 |
CRP Discharge | ≤20 mg/l | 58 | 77.3 | 12 | 46.2 | 0.0036 | ||
>20 mg/l | 17 | 22.7 | 14 | 53.8 | ||||
Time point of infection | Early | 49 | 63.3 | 16 | 57.1 | 0.5446 | ||
Late | 28 | 36.7 | 12 | 42.9 | ||||
Extent of infection | Superficial | 2 | 2.6 | 1 | 3.4 | 1.000 | ||
Deep | 75 | 97.4 | 28 | 96.6 | ||||
Metabolic diseasec
| Yes | 12 | 15.6 | 7 | 24.1 | 0.3061 | ||
No | 65 | 84.4 | 22 | 75.9 | ||||
Re-infection | Yes | 23 | 29.9 | 14 | 48.3 | 0.0764 | ||
No | 54 | 70.1 | 15 | 51.7 | ||||
Implantat preservation | After fracture consolidation | 40 | 53.3 | 7 | 24.1 | 0.0073 | ||
Before fracture consolidation | 35 | 46.6 | 22 | 75.9 |
Variable | Description | Survival of the implant until bony consolidationa
|
p-valueb
| |||||
---|---|---|---|---|---|---|---|---|
Yes | No | |||||||
n
| Mean or % | SD |
n
| Mean or % | SD | |||
Gender | Male | 38 | 80.9 | 37 | 64.9 | 0.0712 | ||
Female | 9 | 19.1 | 20 | 35.1 | ||||
Age | 47 | 55.5 | 18.5 | 57 | 52.1 | 18.9 | 0.3006 | |
Stay at ICU | days | 47 | 4.5 | 6.5 | 57 | 3.1 | 5.5 | 0.4337 |
Initial procedure | Open | 45 | 95.7 | 1 | 1.8 | 0.5881 | ||
Closed | 2 | 4.3 | 56 | 98.2 | ||||
Tissue damage | Open Grade 0-2 | 7 | 14.9 | 11 | 19.3 | 0.042 | ||
Open Grade 3-4 | 2 | 4.3 | 11 | 19.3 | ||||
Closed | 38 | 80.9 | 35 | 61.4 | ||||
Identification of a | Yes | 43 | 91.5 | 48 | 84.2 | 0.2640 | ||
microbial strain | No | 4 | 8.5 | 9 | 15.8 | |||
Presence of a bacterial mixture | Yes | 5 | 10.6 | 15 | 26.3 | 0.0413 | ||
No | 38 | 80.8 | 33 | 57.9 | ||||
No detectable germ | 4 | 8.5 | 9 | 15.8 | ||||
Change in microbial strain during treatment | Yes | 40 | 85.1 | 40 | 70.2 | 0.0721 | ||
No | 7 | 14.9 | 17 | 29.8 | ||||
Gram Stain | Positive | 34 | 72.3 | 39 | 68.4 | 0.8615 | ||
Negative | 8 | 17.0 | 10 | 17.5 | ||||
None | 5 | 10.6 | 8 | 14.0 | ||||
Bacterial metabolism | Aerobic | 3 | 6.4 | 4 | 7.0 | 0.2172 | ||
Anaerobic | 1 | 2.1 | 2 | 3.5 | ||||
Facultative anaerobic | 38 | 80.9 | 37 | 64.9 | ||||
Facultative aerobic | 0 | 0.0 | 5 | 8.8 | ||||
No detectable germ | 5 | 10.6 | 9 | 15.8 | ||||
Bacterial load | Plentiful | 10 | 21.3 | 17 | 29.8 | 0.7030 | ||
Numerous | 17 | 36.2 | 15 | 26.3 | ||||
Sporadic | 13 | 27.7 | 14 | 24.6 | ||||
Enrichment | 2 | 4.3 | 2 | 3.5 | ||||
No detectable germ | 5 | 10.6 | 9 | 15.8 | ||||
Number of lavages until eradication | sponge changes 0 | 23 | 48.9 | 27 | 47.4 | 0.6821 | ||
sponge changes 1 | 13 | 27.7 | 13 | 22.8 | ||||
sponge changes 2 | 4 | 8.5 | 9 | 15.8 | ||||
sponge changes ≥3 times | 7 | 14.9 | 4 | 7.0 | ||||
Never be eradicated | 0 | 0.0 | 4 | 7.0 | ||||
CRP Initial | [mg/l] | 45 | 81.5 | 94.1 | 50 | 72.6 | 85.1 | 0.7201 |
CRP Maximum | [mg/l] | 47 | 147.6 | 102.6 | 52 | 115.2 | 95.2 | 0.2187 |
CRP Discharge | [mg/l] | 46 | 23.2 | 39.2 | 53 | 24.9 | 32.9 | 0.6668 |
CRP Discharge | ≤20 mg/l | 34 | 73.9 | 35 | 66.0 | 0.5113 | ||
>20 mg/l | 12 | 26.1 | 18 | 34.0 | ||||
Time Point of Infection | Early | 36 | 76.6 | 27 | 48.2 | 0.0032 | ||
Late | 11 | 23.4 | 29 | 51.8 | ||||
Extent of Infection | Superficial | 0 | 0.0 | 2 | 3.5 | 0.4998 | ||
Deep | 47 | 100.0 | 55 | 96.5 | ||||
Metabolic diseasec
| Yes | 8 | 17.0 | 9 | 15.8 | 0.8657 | ||
No | 39 | 82.0 | 48 | 84.2 | ||||
Re-infection | Yes | 14 | 29.8 | 23 | 40.4 | 0.3951 | ||
No | 33 | 70.2 | 34 | 59.6 | ||||
Curing the Infection | Yes | 40 | 85.1 | 35 | 61.4 | 0.0086 | ||
No | 7 | 14.9 | 22 | 38.6 |
Cure of Infection | Multiple logistic regression modela
| |||
---|---|---|---|---|
Influencing Parameters | vs. | OR | [95% CI] |
p
|
CRP – discharge ≤ 20 mg/l | > 20 mg/l | 3.6 | [1.31-10.08] | 0.0134 |
Change of microbial strain Yes | No | 3.2 | [1.13-8.99] | 0.0289 |
Survival of the implant | Multiple logistic regression modela
| |||
---|---|---|---|---|
Influencing Parameter | vs. | OR | [95% CI] |
p
|
Bacterial mixture Yes | No | 5.0 | [1.41–17.92] | 0.0126 |
No detectable germ | No | 3.4 | [0.82–14.11] | 0.0932 |
Time point of infection late | acute | 5.1 | [1.93–13.41] | 0.0010 |
Soft tissue damage | ||||
Open grade 0–2 | Closed | 2.6 | [0.76–8.78] | 0.1262 |
Open grade 3–4 | Closed | 10.2 | [1.88–55.28] | 0.0072 |