Table 4.
Risk factors for microbiologically persistent Staphylococcus aureus prosthetic joint infection.
| Eradicated | Non-eradicated | p-valuea | OR for non-eradication (95% CI)b | |
|---|---|---|---|---|
| Age, years, median (range) | 73 (46–91) | 76.5 (39–92) | 0.22 | |
| Age ≥ 80 | 18.6% (12/59) | 42.5% (17/40) | 0.013 | 3.83 (1.44–10.23) |
| Obesity (BMI > 30 kg/m2) | 33.3% (19/57) | 22.5% (9/40) | 0.25 | |
| Sex (female) | 54.2% (32/59) | 45.0% (18/40) | 0.37 | |
| Hemoglobin, g/L, median (range) | 124 (82–153) | 123 (83–166) | 0.40 | |
| ASA ≥ 3 | 39.0% (23/59) | 65.0% (26/40) | 0.01 | 3.30 (1.30–8.35) |
| Active smoking | 10.2% (6/59) | 10.0% (4/40) | 1.00 | |
| COPD | 8.5% (5/59) | 10.0% (4/40) | 1.00 | |
| Autoimmune disease | 10.2% (6/59) | 20.0% (8/40) | 0.17 | |
| Diabetes | 8.5% (5/59) | 15.0% (6/40) | 0.34 | |
| Immunosuppressionc | 11.9% (7/52) | 15.0% (6/40) | 0.65 | |
| Drug abuse | 1.7% (1/59) | 5.0% (2/40) | 0.56 | |
| Malignancy | 1.7% (1/59) | 5.0% (2/40) | 0.56 | |
| Prior surgery | 25.4% (15/44) | 30.0% (12/40) | 0.62 | |
| Localization | ||||
| Hip | 60.3% (41/68) | 39.7% (27/68) | 0.83 | |
| Knee | 58.1% (18/31) | 41.9% (13/31) | ||
| Indication for surgeryd | ||||
| Osteoarthritis | 72.9% (43/ 59) | 51.4% (19/37) | 0.05 | Reference |
| Rheumatoid arthritis | 3.4% (2/57) | 5.4% (2/37) | 0.64 | 2.27 (0.29–17.97) |
| Aseptic loosening | 3.4% (2/59) | 0.0% (0/39) | 0.52 | * |
| Fracture | 13.6% (8/59) | 27.0% (10/37) | 0.10 | 2.56 (0.84–7.82) |
| Type of implant | ||||
| Cemented | 94.9% (56/59) | 92.5% (3/40) | 0.62 | |
| Uncemented | 5.1% (3/59) | 7.5% (3/40) | ||
| Type of surgery | ||||
| Primary | 83.1% (49/59) | 80.% (32/40) | 0.70 | |
| Revision | 16.9% (10/59) | 20.0% (8/40) | ||
| Classification | ||||
| Early | 67.8% (40/59) | 42.5% (17/40) | 0.02 | 0.31 (0.10–0.95) |
| Chronic | 11.9% (7/59) | 25.0% (10/40) | 0.19 | Reference |
| Late acute | 20.3% (12/59) | 32.5% (13/40) | 0.23 | 0.87 (0.25–3.00) |
| Positive blood culture | ||||
| No | 45.8% (27/59) | 42.5% (17/40) | 0.75 | |
| Yes | 32.2% (19/59) | 37.5% (15/40) | 0.59 | |
| Yes (>4 weeks before infection) | 3.9% (2/59) | 10.0% (4/40) | 0.18 | |
| No sample | 18.6% (11/59) | 10.0% (4/40) | 0.24 | |
| Symptoms at diagnosis | ||||
| Wound secretion | 66.1% (39/59) | 50.0% (20/40) | 0.11 | 0.49 (0.21–1.13) |
| Pain | 71.2% (42/59) | 87.5% (35/40) | 0.06 | 3.59 (1.15–11.24) |
| Fever | 54.2% (32/59) | 50.0% (20/20) | 0.68 | |
| Redness | 61.0% (36/59) | 60.0% (24/40) | 0.92 | |
| Sinus tract | 16.9% (10/59) | 20.0% (8/40) | 0.70 | |
| C-reactive protein High (>150 mg/L) | 181.9/ 137.9 | 167.4/156.0 | 0.86 | |
| Blood, leukocyte cell count (>15 × 109/L) | 25.5% (1/51) | 33.3% (12/36) | 0.48 | |
| Change of mobile components | 74.6% (44/59) | 57.5% (23/40) | 0.08 | 0.46 (0.19–1.09) |
| >1 DAIR | 8.5% (5/59) | 15.0% (6/40) | 0.31 | |
| Biofilm-active treatment | 79.7% (47/59) | 47.5% (19/40) | 0.004 | 0.70 (0.11–0.70) |
| Guideline-compliant treatment+ | 84.7% (50/59) | 70.3% (26/37) | 0.09 | 0.42 (0.16–1.12) |
| Polymicrobial PJI | 33.9% (20/59) | 7.5% (3/40) | 0.003 | 0.13 (0.04–0.50) |
| S. aureus antibiotic resistance | 1.7% (1/59) | 20.0% (8/40) | 0.003 | 15.99 (1.88–135.91) |
aχ2-test, Fisher’s exact test, or Mann–Whitney U test.
bCovariates with possible associations (p < 0.12) were entered into logistic regression model with adjustments for sex and age. Odds ratios with p-values <0.05 are in bold.
cRheumatoid arthritis, systemic lupus erythematosus, sarcoidosis.
dTen patients had other indications.
*Too few patients to perform a valid statistical analysis.
+Three patients who died before oral treatment stopped were excluded.