Does D-Dimer really help in the diagnosis of chronic periprosthetic joint infections (PJI)? A case-control study

Introduction The differential diagnosis between aseptic and septic total joint arthroplasty (TJA) revision is fundamental in order to be successful in the surgical treatment. Several serum biomarkers have been proposed as gold standards in the diagnosis of Periprosthetic Joint Infections (PJI). The aim of the current study was (1) to evaluate serum levels of D-dimer in a retrospective series of PJIs diagnosed by traditional methods and (2) to compare the D-dimer performance as a diagnostic test with other well established PJI biomarkers in a case-control study. Materials and methods A total of 159 TJA revisions were included in the study database: 55 implants in 55 patients met the inclusion criteria. The final study group included 33 aseptic and 22 septic (with micro-organism isolation) TJA revisions; these two groups were not statistically different in terms of demographics. All patients were preoperatively tested with the following serologic tests: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen, D-dimer and white blood cell (WBC) count. A standard univariate logistic analysis was performed in order to investigate the association between chronic PJI and the serologic tests. Results A gram-positive microorganism was isolated in 15 patients whereas a gram-negative microorganism was isolated in 7 patients. Univariate analysis showed that high D-dimer, ESR or fibrinogen were not associated with a PJI occurrence, whereas high CRP and WBC count >10.000 cells/mm3 were significantly elevated in chronic PJI patients. A multivariate analysis confirmed that leukocytosis was a significant predictor of PJI. Conclusions This study showed that D-dimer had a low sensitivity and specificity in diagnosing chronic PJI, especially when evaluated as a single diagnostic biomarker.