Despite the availability of a battery of tests, the diagnosis of periprosthetic joint infection (PJI) continues to be challenging. Serum D-dimer assessment is a widely available test that detects fibrinolytic activities that occur during infection. We hypothesized that patients with PJI may have a high level of circulating D-dimer and that the presence of a high level of serum D-dimer may be a sign of persistent infection in patients awaiting reimplantation.
This prospective study was initiated to enroll patients undergoing primary and revision arthroplasty. Our cohort consisted of 245 patients undergoing primary arthroplasty (n = 23), revision for aseptic failure (n = 86), revision for PJI (n = 57), or reimplantation (n = 29) or who had infection in a site other than a joint (n = 50). PJI was defined using the Musculoskeletal Infection Society criteria. In all patients, serum D-dimer level, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level were measured preoperatively.
The median D-dimer level was significantly higher (p < 0.0001) for the patients with PJI (1,110 ng/mL [range, 243 to 8,487 ng/mL]) than for the patients with aseptic failure (299 ng/mL [range, 106 to 2,571 ng/mL). Using the Youden index, 850 ng/mL was determined as the optimal threshold value for serum D-dimer for the diagnosis of PJI. Serum D-dimer outperformed both ESR and serum CRP, with a sensitivity of 89% and a specificity of 93%. ESR and CRP had a sensitivity of 73% and 79% and a specificity of 78% and 80%, respectively. The sensitivity and specificity of ESR and CRP combined was 84% (95% confidence interval [CI], 76% to 90%) and 47% (95% CI, 36% to 58%), respectively.
It appears that serum D-dimer is a promising marker for the diagnosis of PJI. This test may also have a great utility for determining the optimal timing of reimplantation.
Level of Evidence:
Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.