@article{BoelchRothArnholdtetal.2018,
  author    = {Boelch, Sebastian P. and Roth, Magnus and Arnholdt, Joerg and Rudert, Maximilian and Luedemann, Martin},
  title     = {Synovial fluid aspiration should not be routinely performed during the two-stage exchange of the knee},
  series = {BioMed Research International},
  volume    = {2018},
  journal   = {BioMed Research International},
  number    = {6720712},
  doi       = {10.1155/2018/6720712},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176800},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{BoelchWeissenbergerSpohnetal.2018,
  author    = {Boelch, Sebastian Philipp and Weissenberger, Manuel and Spohn, Frederik and Rudert, Maximilian and Luedemann, Martin},
  title     = {Insufficient sensitivity of joint aspiration during the two-stage exchange of the hip with spacers},
  series = {Journal of Orthopedic Surgery and Research},
  volume    = {13},
  journal   = {Journal of Orthopedic Surgery and Research},
  number    = {7},
  doi       = {10.1186/s13018-017-0703-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175576},
  year      = {2018},
  abstract  = {Background: Evaluation of infection persistence during the two-stage exchange of the hip is challenging. Joint aspiration before reconstruction is supposed to rule out infection persistence. Sensitivity and specificity of synovial fluid culture and synovial leucocyte count for detecting infection persistence during the two-stage exchange of the hip were evaluated. Methods: Ninety-two aspirations before planned joint reconstruction during the two-stage exchange with spacers of the hip were retrospectively analyzed. Results: The sensitivity and specificity of synovial fluid culture was 4.6 and 94.3\%. The sensitivity and specificity of synovial leucocyte count at a cut-off value of 2000 cells/μl was 25.0 and 96.9\%. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values were significantly higher before prosthesis removal and reconstruction or spacer exchange (p = 0.00; p = 0.013 and p = 0.039; p = 0.002) in the infection persistence group. Receiver operating characteristic area under the curve values before prosthesis removal and reconstruction or spacer exchange for ESR were lower (0.516 and 0.635) than for CRP (0.720 and 0.671). Conclusions: Synovial fluid culture and leucocyte count cannot rule out infection persistence during the two-stage exchange of the hip.},
  language  = {en}
}