Table 3.
Risk factors associated with treatment success and failure among patients with Staphylococcus aureus prosthetic joint infection.
| Success | Failure | p-valuea | OR for failure (95% CI)b | |
|---|---|---|---|---|
| Age, years, median (range) | 72.5 (48–91) | 75 (39–92) | 0.39 | |
| Age ≥ 80 | 22.0% (11/50) | 36.7% (18/49) | 0.11 | 1.96 (0.74–5.17) |
| Obesity (BMI > 30 kg/m2) | 35.4% (17/48) | 22.4% (11/49) | 0.15 | |
| Sex (female) | 52.0% (26/50) | 49.0% (24/49) | 0.76 | |
| Hemoglobin, g/L, median (range) | 124.5 (82–153) | 123.0 (83–166) | 0.54 | |
| ASA ≥ 3 | 36.0% (18/50) | 63.2% (31/49) | 0.007 | 3.61 (1.45–9.01) |
| Active smoking | 10.0% (5/50) | 10.2% (5/49) | 1.00 | |
| COPD | 8.0% (4/50) | 10.2% (5/49) | 0.74 | |
| Autoimmune diseasec | 10.0% (5/50) | 22.4% (11/49) | 0.02 | 5.58 (1.37–22.65) |
| Diabetes | 6.0% (3/50) | 16.3% (8/49) | 0.12 | |
| Immunosuppression | 10.0% (5/50) | 16.3% (8/49) | 0.39 | |
| Drug abuse | 0.0% (0/50) | 6.1% (3/49) | 0.12 | |
| Malignancy | 0.0% (0/50) | 4.1% (2/49) | 0.24 | |
| Prior surgery | 22.0% (11/50) | 32.7% 16/49) | 0.23 | |
| Localization | ||||
| Hip | 68.0% (34/50) | 69.4% (34/49) | 0.88 | |
| Knee | 32.0% (16/50) | 30.6% (15/49) | ||
| Indication for surgeryd | ||||
| Osteoarthritis | 72.0% (36/50) | 56.5% (26/46) | 0.11 | Reference |
| Rheumatoid arthritis | 4.0% (2/50) | 4.3% (2/46) | 0.93 | 1.47 (0.18–11.11) |
| Aseptic loosening | 4.0% (2/50) | 0% (0/49) | 0.27 | * |
| Fracture | 16.0% (8/50) | 21.7% (10/46) | 0.47 | 1.72 (0.55–5.26) |
| Type of implant | ||||
| Cemented | 94.0% (47/50) | 93.9% (46/49) | 0.98 | |
| Uncemented | 6.0% (3/50) | 6.1% (3/49) | ||
| Type of surgery | ||||
| Primary | 84.0% (42/50) | 79.6% (39/49) | 0.57 | |
| Revision | 16.0% (8/50) | 20.4% (10/49) | ||
| Classification | ||||
| Early | 78.0% (39/50) | 36.7% (18/49) | 0.001 | 0.02 (0.00–0.19) |
| Chronic | 0.0% (0/50) | 34.7% (17/49) | 0.001 | Reference |
| Late acute | 22.0% (11/50) | 28.6% (14/49) | 0.45 | 0.07 (0.01–0.63) |
| Positive blood culture | ||||
| No | 48.0% (24/50) | 40.8% (20/49) | 0.47 | |
| Yes | 36.0% (18/50) | 32.7% (16/49) | 0.73 | |
| Yes (>4 weeks before infection) | 0.0% (0/50) | 12.2% (6/49) | 0.12 | |
| No sample | 16.0% (8/50) | 14.3% (7/49) | 0.812 | |
| Symptoms at diagnosis | ||||
| Wound secretion | 70.0% (35/50) | 49.0% (24/49) | 0.03 | 0.40 (0.18–0.93) |
| Pain | 32.0% (16/50) | 87.8% (43/49) | 0.02 | 3.89 (1.32–11.45) |
| Fever | 56.0% (28/50) | 49.0% (24/49) | 0.48 | |
| Redness | 66.0% (33/50) | 55.1% (27/49) | 0.31 | |
| Sinus tract | 14.0% (7/50) | 22.4% (11/38) | 0.31 | |
| C-reactive protein, high (>150 mg/L) | 50.0% (25/50) | 46.9% (23/49) | 0.84 | |
| Blood, leukocyte cell count (>15 × 109/L) | 20.9% (9/43) | 29.5% (14/44) | 0.26 | |
| Change of mobile components | 70.0% (35/50) | 65.3% (32/49) | 0.69 | |
| >1 DAIR | 10.0% (5/50) | 12.2% (6/49) | 0.72 | |
| Biofilm-active treatment | 90.0%(45/50) | 33.8% (23/49) | 0.001 | 0.09 (0.03–0.28) |
| Guideline-compliant treatment + | 84.0%(42/50) | 73.9% (34/46) | 0.22 | |
| Polymicrobial PJI | 38.0% (19/50) | 8.2% (4/49) | 0.001 | 0.13 (0.04–0.44) |
| S. aureus antibiotic resistance | 0.0% (0/50) | 18.3% (9/49) | 0.001 | |
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.