TABLE 1.
Characteristics of study subjects
| Characteristic | Values for subjects in: |
|
|---|---|---|
| Derivation set (n = 204) | Validation set (n = 204) | |
| Mean (range) age (yr) | 65.2 (18–93) | 65.4 (30–89) |
| No. (%) of male subjects | 95 (46.6) | 110 (53.9) |
| No. (%) of subjects with the following type of prosthetic joint: | ||
| Hip | 63 (30.9) | 64 (31.4) |
| Knee | 141 (69.1) | 140 (68.6) |
| No. (%) of subjects with the presence of a sinus tract | 30 (14.7) | 22 (10.8) |
| No. (%) of subjects receiving antibiotics within 4 wk prior to surgery | 56 (27.5) | 79 (38.7) |
| No. (%) of subjects with the following preoperative laboratory findingsa : | ||
| White blood cell count of >10 × 109/liter | 40 (19.6) | 26 (12.7) |
| Erythrocyte sedimentation rate of >30 mm/h | 74 (36.3) | 83 (40.7) |
| Serum C-reactive protein concn of >10 mg/liter | 96 (47.1) | 102 (50.0) |
| No. (%) of subjects with: | ||
| Visible purulence at implant site | 88 (43.1) | 97 (47.5) |
| Acute inflammation on histopathology | 55 (26.9) | 60 (29.4) |
| Identical organism identified in ≥2 periprosthetic tissue specimen cultures | 62 (30.4) | 49 (24.0) |
| No. (%) of subjects in the following category: | ||
| Prosthetic joint infection | 103 (50.5) | 110 (53.9) |
| Aseptic failure | 101 (49.5) | 94 (46.1) |
a
The white blood cell count was the result within 1 week prior to surgery; other laboratory findings were the results closest to the time of surgery within the 6 months preceding the surgery.