Abstract
Aim
Diagnosis of periprosthetic joint infection (PJI) presents a real challenge in some patients. Batteries of tests are available to reach this diagnosis. It is unknown if blood cultures have any role in diagnosis of PJI. The objective of this study was to evaluate whether blood cultures, taken in a group of patients with PJI, was useful in identifying the infecting pathogen.
Methods
The institutional database was used to identify all patients treated at our institution between 2000 – 2015 for PJI according to the latest MSIS criteria. There were a total of 864 patients with mean age of 68 years. Synovial fluid sample and/or deep tissue samples were analyzed and cultured in all of these patients. In 371 (42.9%) patients with PJI, blood cultures were also taken. Statistical analyses were performed for correlation purposes.
Results
In 246 (66.3%) patients in whom an organism was isolated from joint fluid, blood cultures were negative. 32 (8.6%) patients had both negative blood and synovial joint tissue culture. Of the 93 (25%) patients with positive blood cultures, 77 (82.7%) patients had identical organism in the joint and 16 (17.2%) had different organisms. Interestingly one infection that was fungal in nature showed no growth on tissue/fluid culture, yet a fungal organism was isolated in blood culture. Additionally, of the 93 patients with positive blood cultures, 57 (61.2%) had signs of systemic sepsis with leukocytosis and increased PMN/left shift. Within the 57 patients, 50 (87.7%) had identical blood and joint culture and 7 (12.2%) were from different culture organisms. 36 (38.7%) patients had subclinical infection with no signs of systemic sepsis.
Discussion
Although this study does not advocate the routine use of blood culture for diagnosis of PJI, the finding that blood culture is successful in isolating the infecting organism as the joint in a handful of cases is compelling. Thus, the result of blood culture when performed should be considered as representative of the infecting organism in PJI cases.
