Determination of D - lactate in synovial fluid for the diagnosis of bacterial infection

Objectives Periprosthesic infection (PJI) is a serious complication after arthoplasty, which causes permanent pain, an increase in the stay length of patients in the hospital, numerous revision surgeries, functional disability and even mortality. Detection of infectious complications remains a serious problem. There is no “gold” standard for diagnosis. The most acceptable diagnostic test is aspiration of synovial fluid (SF) to perform general and differential studies, as well as seeding. The main disadvantage of the latter technique is the duration of its implementation. Recently, the increasing relevance in the determination of bacterial metabolites in biological fluids. Studies on the presence of D-lactate in synovial fluid are rare.

Purpose To determine the possibility of determining D-lactate in synovial fluid for the early diagnosis of periprosthetic infection.

Methods The main group of 24 patients was represented by patients with PJI. The control group (n = 24) included patients with degenerative-dystrophic lesions of the knee joint (n = 12) and patients with chronic injuries of intra-articular structures (n = 12). The age of the patients was 52 (41; 61). The distribution of the studied persons by gender was as follows: men - 29 (60.5 %), women 19 (39.5 %).

Qualitative and quantitative assessment of D-lactate in synovial fluid was determined using the D-Lactam test system, the test result was ready in 1 hour.

Statistical analysis of the results of the study was carried out with the analytical package Statistica 10.0. ROC analysis with the construction of ROC curves and calculation of the “cut-off” values of D-lactate was performed in the program MedCalc 10.2.

Results and Conclusion Results. In the patients of the control group (n = 24), the median of the D-lactate level in the SF was 0.32 (0.26; 0.37), max - 0.48 mmol/l, min - 0.11 mmol/l. No statistically significant differences in the concentration of D-lactate in the SJ in the group were found (p> 0.05).

In patients of the main group (n = 24) with inflammatory purulent processes, the median concentration of D-lactate in SJ was 1.44 (0.99; 1.70) mmol/l, max - 2.70 mmol/l, min - 0, 28 mmol/l.

In the course of the ROC analysis, it was found that the level of D-lactate, exceeding 0.32 mmol/l, indicates the presence of bacterial contamination in the patient with a sensitivity of 95.65 % (95 % CI: 78.0 … 99.3) and specificity 100 % (95 % CI: 85.6 … 100), the area under the curve AUC = 0.968, which makes it possible to consider the determination of the level of D-lactate as a good method of express diagnosis of a bacterial infection of a native and prosthetic joint.

Conclusion. The presence of high levels of D-lactate in the synovial fluid exceeding 0.48 mmol/l, with the presence of local inflammatory changes with a high degree of confidence (p <0.01) indicates the presence in the patient of an infectious process in the articular area.

Stichwörter arthroplasty, periprosthesic infection, knee joint, diagnosis, D-lactate

Publication History

Article published online:
15 October 2020