TABLE 1 

Demographic, perioperative biochemical, microbiological, and histopathological characteristics of study subjects

CharacteristicNo. of subjects meeting IDSA criteria for PJI or parameter value (%, unless IQR is specified)aP value
No (n = 252)Yes (n = 117)
Age, yr [median (IQR)]64 (56, 74)62 (56, 70)0.2
Female sex148 (59)45 (38)<0.001
Prosthetic joint type0.01
    Hip106 (42)32 (28)
    Knee104 (41)56 (48)
    Shoulder32 (13)17 (15)
    Elbow10 (4)12 (10)
Indication for primary arthroplasty0.5
    Osteoarthritis188 (75)87 (74)
    Rheumatoid arthritis12 (5)8 (7)
    Fracture/trauma28 (11)16 (14)
    Avascular necrosis9 (4)2 (2)
    Tumor4 (2)2 (2)
    Native septic arthritis2 (1)0
    Developmental dysplasia7 (3)1 (1)
    Other01 (1)
Prior revision arthroplasty performed on index joint101 (41)73 (63)<0.001
Documented history of PJI35 (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
    Pain244 (97)97 (83)<0.001
    Erythema along incision2 (1)23 (20)<0.001
    Swelling18 (7)34 (29)<0.001
    Drainage from the incision1 (0.4)42 (36)<0.001
    Sinus tract036 (31)
    Fever5 (2)16 (14)<0.001
Antibiotics in the 4 wks prior to surgery17 (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)01 (1)
    Resection with insertion of a spacer24 (4)73 (62)
    Debridement and implant retention10 (4)27 (23)
    Amputation02 (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 performed100 (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 culture7 (7)44 (75)<0.001
Pre- and/or intraoperative synovial fluid culture performed121 (48)65 (56)0.2
Positive synovial fluid culture7 (6)42 (65)<0.001
Sonicate culture performed41 (16)39 (33)<0.001
    Positive sonicate culture1 (2)23 (59)<0.001
Histopathology specimen obtained207 (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.