TABLE 1 .
Demographic, perioperative biochemical, microbiological, and histopathological characteristics of study subjects
| Characteristic | No. of subjects meeting IDSA criteria for PJI or parameter value (%, unless IQR is specified)a |
P value | |
|---|---|---|---|
| No (n = 252) | Yes (n = 117) | ||
| Age, yr [median (IQR)] | 64 (56, 74) | 62 (56, 70) | 0.2 |
| Female sex | 148 (59) | 45 (38) | <0.001 |
| Prosthetic joint type | 0.01 | ||
| Hip | 106 (42) | 32 (28) | |
| Knee | 104 (41) | 56 (48) | |
| Shoulder | 32 (13) | 17 (15) | |
| Elbow | 10 (4) | 12 (10) | |
| Indication for primary arthroplasty | 0.5 | ||
| Osteoarthritis | 188 (75) | 87 (74) | |
| Rheumatoid arthritis | 12 (5) | 8 (7) | |
| Fracture/trauma | 28 (11) | 16 (14) | |
| Avascular necrosis | 9 (4) | 2 (2) | |
| Tumor | 4 (2) | 2 (2) | |
| Native septic arthritis | 2 (1) | 0 | |
| Developmental dysplasia | 7 (3) | 1 (1) | |
| Other | 0 | 1 (1) | |
| Prior revision arthroplasty performed on index joint | 101 (41) | 73 (63) | <0.001 |
| Documented history of PJI | 35 (14) | 63 (54) | <0.001 |
| No. of days of symptoms prior to surgery [median (IQR)] | 288 (123, 633) | 114 (39, 324) | 0.001 |
| Implant age, days [median (IQR)] | 1,497 (520, 3,865) | 479 (166, 1,391) | <0.001 |
| Presenting symptoms | |||
| Pain | 244 (97) | 97 (83) | <0.001 |
| Erythema along incision | 2 (1) | 23 (20) | <0.001 |
| Swelling | 18 (7) | 34 (29) | <0.001 |
| Drainage from the incision | 1 (0.4) | 42 (36) | <0.001 |
| Sinus tract | 0 | 36 (31) | |
| Fever | 5 (2) | 16 (14) | <0.001 |
| Antibiotics in the 4 wks prior to surgery | 17 (7) | 60 (51) | <0.001 |
| Surgery performed | <0.001 | ||
| Revision arthroplasty (including one-stage exchange) | 218 (87) | 14 (12) | |
| Resection arthroplasty (with or without arthrodesis) | 0 | 1 (1) | |
| Resection with insertion of a spacer | 24 (4) | 73 (62) | |
| Debridement and implant retention | 10 (4) | 27 (23) | |
| Amputation | 0 | 2 (2) | |
| Preoperative C-reactive protein concn, mg/liter [median (IQR)] | 3 (3, 6) | 25 (9, 56) | <0.001 |
| Preoperative erythrocyte sedimentation rate, mm/h [median (IQR)] | 9 (4, 19) | 29 (17, 52) | <0.001 |
| Preoperative synovial fluid aspirate performed | 100 (40) | 60 (51) | 0.04 |
| No. of leukocytes/µl in synovial fluid [median (IQR)] | 872 (365, 2,000) | 34048 (13355, 71502) | <0.001 |
| % neutrophils in synovial fluid [median (IQR)] | 14 (6, 51) | 91 (84, 96) | <0.001 |
| Positive synovial fluid culture | 7 (7) | 44 (75) | <0.001 |
| Pre- and/or intraoperative synovial fluid culture performed | 121 (48) | 65 (56) | 0.2 |
| Positive synovial fluid culture | 7 (6) | 42 (65) | <0.001 |
| Sonicate culture performed | 41 (16) | 39 (33) | <0.001 |
| Positive sonicate culture | 1 (2) | 23 (59) | <0.001 |
| Histopathology specimen obtained | 207 (82) | 68 (58) | <0.001 |
| No. of microbiological specimens obtained [median (IQR)] | 3 (3, 4) | 5 (4, 6) | <0.001 |
| No. of tissue cultures performed [median (IQR)] | 3 (2, 3) | 3 (3, 4) | <0.001 |
a
The number of subjects meeting Infectious Diseases Society of America (IDSA) criteria for prosthetic joint infection (PJI) infection or parameter value (shown as a percentage, unless interquartile range [IQR] is specified) is shown.