TY  - JOUR
A1  - Boelch, Sebastian P.
A1  - Roth, Magnus
A1  - Arnholdt, Joerg
A1  - Rudert, Maximilian
A1  - Luedemann, Martin
T1  - Synovial fluid aspiration should not be routinely performed during the two-stage exchange of the knee
JF  - BioMed Research International
N2  - Purpose. Detection of infection persistence during the two-stage exchange of the knee for periprosthetic joint infection is challenging. Synovial fluid culture (SFC) and synovial white blood cell count (SWBCC) before joint reimplantation are widespread diagnostic means for this indication. The sensitivity and specificity of SFC and of SWBCC for infection persistence before planned reimplantation were evaluated. Methods. 94 two-stage exchanges of the knee with synovial fluid aspiration performed after a drug holiday of at least 14 days and before reimplantation or spacer exchange (planned reimplantation) were retrospectively analyzed. Only cases with at least 3 intraoperative samples at planned reimplantation were included. SFC and SWBCC were compared to pathogen detection (SFC\(_{(culture)}\)/SWBCC\(_{(culture)}\) and to histopathological signs of infection persistence (SFC\(_{(histo)}\)/SWBCC\(_{(histo)}\) from intraoperative samples at planned reimplantation. For SFC, the sensitivity and specificity were calculated. For SWBCC, the optimal cut-off value with its sensitivity and specificity was calculated with the Youden-Index. Results. Sensitivity and specificity of SFC\(_{(culture)}\) were 0.0% and 98.9%. Sensitivity and specificity of SFC\(_{(histo)}\) were 3.4% and 100%. The optimal cut-off value for SWBCC\(_{(culture)}\) was 4450 cells/μl with a sensitivity of 50.0% and a specificity of 86.5%. The optimal cut-off value for SWBCC\(_{(histo)}\) was 3250 cells/μl with a sensitivity of 35.7% and a specificity of 92.9%. Conclusion. The detection of infection persistence remains challenging and a consented approach is lacking. The results do not warrant the routine performance of SFC during the two-stage exchange at the knee. SWBCC can be used to confirm infection persistence at high cut-offs, but they only occur in few patients and are therefore inappropriate for the routine use.
KW  - knee
KW  - two-stage exchange
KW  - Synovial Fluid Aspiration
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176800
VL  - 2018
IS  - 6720712
ER  - 
TY  - JOUR
A1  - Wagenbrenner, Mike
A1  - Heinz, Tizian
A1  - Horas, Konstantin
A1  - Jakuscheit, Axel
A1  - Arnholdt, Joerg
A1  - Mayer-Wagner, Susanne
A1  - Rudert, Maximilian
A1  - Holzapfel, Boris M.
A1  - Weißenberger, Manuel
T1  - Impact of Tranexamic Acid on Chondrocytes and Osteogenically Differentiated Human Mesenchymal Stromal Cells (hMSCs) In Vitro
JF  - Journal of Clinical Medicine
N2  - The topical application of tranexamic acid (TXA) helps to prevent post-operative blood loss in total joint replacements. Despite these findings, the effects on articular and periarticular tissues remain unclear. Therefore, this in vitro study examined the effects of varying exposure times and concentrations of TXA on proliferation rates, gene expression and differentiation capacity of chondrocytes and human mesenchymal stromal cells (hMSCs), which underwent osteogenic differentiation. Chondrocytes and hMSCs were isolated and multiplied in monolayer cell cultures. Osteogenic differentiation of hMSCs was induced for 21 days using a differentiation medium containing specific growth factors. Cell proliferation was analyzed using ATP assays. Effects of TXA on cell morphology were examined via light microscopy and histological staining, while expression levels of tissue-specific genes were measured using semiquantitative RT-PCR. After treatment with 50 mg/mL of TXA, a decrease in cell proliferation rates was observed. Furthermore, treatment with concentrations of 20 mg/mL of TXA for at least 48 h led to a visible detachment of chondrocytes. TXA treatment with 50 mg/mL for at least 24 h led to a decrease in the expression of specific marker genes in chondrocytes and osteogenically differentiated hMSCs. No significant effects were observed for concentrations beyond 20 mg/mL of TXA combined with exposure times of less than 24 h. This might therefore represent a safe limit for topical application in vivo. Further research regarding in vivo conditions and effects on hMSC functionality are necessary to fully determine the effects of TXA on articular and periarticular tissues.
KW  - tranexamic acid
KW  - hMSCs
KW  - chondrocytes
KW  - osteoarthritis
KW  - toxicity
KW  - differentiation capacity
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219410
SN  - 2077-0383
VL  - 9
IS  - 12
ER  -