[First experiences with fluorodeoxyglucose-positron-emission tomography (FDG-PET) in the evaluation of painful total knee and hip joint replacements]

Wearing face masks as a potential source for inhalation and oral uptake of inanimate toxins - A scoping review

BACKGROUND

From 2020 to 2023 many people around the world were forced to wear masks for large proportions of the day based on mandates and laws. We aimed to study the potential of face masks for the content and release of inanimate toxins.

METHODS

A scoping review of 1003 studies was performed (database search in PubMed/MEDLINE, qualitative and quantitative evaluation).

RESULTS

24 studies were included (experimental time 17 min to 15 days) evaluating content and/or release in 631 masks (273 surgical, 228 textile and 130 N95 masks). Most studies (63%) showed alarming results with high micro- and nanoplastics (MPs and NPs) release and exceedances could also be evidenced for volatile organic compounds (VOCs), xylene, acrolein, per-/polyfluoroalkyl substances (PFAS), phthalates (including di(2-ethylhexyl)-phthalate, DEHP) and for Pb, Cd, Co, Cu, Sb and TiO2.

DISCUSSION

Of course, masks filter larger dirt and plastic particles and fibers from the air we breathe and have specific indications, but according to our data they also carry risks. Depending on the application, a risk-benefit analysis is necessary.

CONCLUSION

Undoubtedly, mask mandates during the SARS-CoV-2 pandemic have been generating an additional source of potentially harmful exposition to toxins with health threatening and carcinogenic properties at population level with almost zero distance to the airways.

Endoglin (CD105) expression differentiates between aseptic loosening and periprosthetic joint infection after total joint arthroplasty

The differentiation between aseptic loosening and periprosthetic joint infection (PJI) after total joint arthroplasty is essential for successful therapy. A better understanding of pathogenesis of aseptic loosening and PJI may help to prevent or treat these complications. Previous investigations revealed an increased vascularization in the periprosthetic membrane in cases of PJI via PET signals. Based on these findings our hypothesis was that PJI is associated with an increased neovascularization in the periprosthetic membrane.

Tissue samples from periprosthetic membranes of the bone-implant interface were investigated histologically for inflammation, wear particles, vascularization and fibrosis. To identify vascular structures antibodies against CD 31, CD 34, factor VIII and CD 105 (endoglin) were applied for immunohistochemical investigations. According to a consensus classification of Morawietz the tissue samples were divided into four types: type I (wear particle induced type, n = 11), type II (infectious type, n = 7), type III (combined type, n = 7) and type IV (indeterminate type, n = 7).

Patients with PJI (type II) showed a pronounced infiltration of neutrophil granulocytes in the periprosthetic membrane and an enhanced neovascularization indicated by positive immunoreaction with antibodies against CD 105 (endoglin). Tissue samples classified as type I, type III and type IV showed significantly less immune reaction for CD 105.

In cases of aseptic loosening and PJI vascularization is found in different expression in periprosthetic membranes. However, in aseptic loosening, there is nearly no neovascularization with CD 105-positive immune reaction. Therefore, endoglin (CD 105) expression allows for differentiation between aseptic loosening and PJI.

Mark B. Coventry Award: synovial C-reactive protein: a prospective evaluation of a molecular marker for periprosthetic knee joint infection

BACKGROUND

C-reactive protein (CRP) serum assays are a standard element of the diagnostic workup for periprosthetic joint infection (PJI). However, because CRP is a marker for systemic inflammation, this test is not specific to PJI.

QUESTIONS/PURPOSES

Our purpose was to assess whether synovial fluid and serum assays alone could differentiate between infected and uninfected revision knee arthroplasties and to determine which of these methods had the greatest diagnostic accuracy.

METHODS

We collected synovial fluid specimens from 66 patients undergoing revision total knee arthroplasty. Patients were judged uninfected or infected by standardized criteria. Synovial CRP levels were measured using an individual CRP assay (15 samples; 10 infected, five uninfected) and a multiplex immunoassay platform (59 samples; 25 infected, 34 uninfected). Results from preoperative standard serum CRP assays conducted were also collected (55 samples; 25 infected, 30 uninfected). Sensitivity, specificity, and receiver operating characteristic curve analyses were performed for each assay with a diagnosis of infection based on previously established criteria.

RESULTS

Synovial CRP concentrations differed between infected and uninfected joints in the multiplex and serum analyses. The area under the curve was 0.84 for the individual assay, 0.91 for the multiplex assay, and 0.88 for the serum CRP assay. Sensitivity and specificity were 70.0% and 100.0% for the individual enzyme-linked immunosorbent assay, 84.0% and 97.1% for the multiplex assay, and 76.0% and 93.3% for the serum CRP assay.

CONCLUSIONS

An assay measuring CRP in synovial fluid may be more accurate in diagnosing PJI than the standard serum CRP assay. We believe such an assay holds promise as a new diagnostic marker for PJI.

Use of 18F-FDG-PET in the diagnosis of endoprosthetic loosening of knee and hip implants

INTRODUCTION

To diagnose septic and aseptic loosening 18-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) has been described with good results for hip arthroplasties. The purpose of the present study was to examine whether there is a difference of feasibility in detecting loosening of hip versus knee prostheses by use of (18)F-FDG-PET.

PATIENTS

Thirty-two patients with lower limb arthroplasty complaints (74 components) were studied preoperatively with (18)F-FDG-PET. The interpretation of (18)F-FDG-PET was done according to evaluated criteria. The final diagnosis based on intraoperative findings in all cases including microbiological examinations.

RESULTS

For hip arthroplasty sensitivity/specificity of (18)F-FDG-PET towards implant loosening was 80%/87%. For infectious loosening of hip endoprostheses sensitivity/specificity was 67%/83%. In knee endoprostheses sensitivity/specificity for loosening was 56%/82% and 14%/89% for infection. The sensitivity of the results for knee and hip joints in regard to infectious versus aseptic loosening was significantly different.

CONCLUSION

We confirm that (18)F-FDG-PET is an appropriate tool to diagnose hip arthroplasty loosening. Differing from that (18)F-FDG-PET showed a significant lower sensitivity/specificity in detecting septic loosening of knee endoprostheses. It may therefore be necessary to use different methods to diagnose loosening of endoprostheses depending on the type of implant which is examined.

FDG-PET for diagnosing prosthetic joint infection: systematic review and metaanalysis

PURPOSE

The aim of this study was to systematically review and metaanalyze published data on the diagnostic performance of (18)F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in detecting prosthetic hip or knee joint infection.

METHODS

A systematic search for relevant studies was performed of the PubMed/MEDLINE and Embase databases. Two reviewers independently assessed the methodological quality of each study. A metaanalysis of the reported sensitivity and specificity of each study was performed. Subgroup analyses were performed if results of individual studies were heterogeneous.

RESULTS

The inclusion criteria were met by 11 studies; there was a total sample size of 635 prostheses. Overall, the studies had good methodological quality. Pooled sensitivity and specificity of FDG-PET for the detection of prosthetic hip or knee joint infection were 82.1% (95%CI = 68.0-90.8%) and 86.6% (95%CI = 79.7-91.4%), respectively. Heterogeneity among the results of individual studies was present (I (2) = 68.8%). Diagnostic performance was influenced by type of joint prostheses (hip prostheses vs. knee prostheses) and type of reconstruction method used (filtered back vs. iterative) (p = 0.0164 and p = 0.0235, respectively).

CONCLUSION

In this metaanalysis, overall diagnostic performance of FDG-PET was moderate to high. Caution is warranted, however, because results of individual studies were heterogeneous and could not be fully explored. Future studies should further explore potential causes of heterogeneity and validate the use of FDG-PET for diagnosing prosthetic joint infection.

Comparison of subtraction arthrography, radionuclide arthrography and conventional plain radiography to assess loosening of total knee arthroplasty / Vergleich von Subtraktionsarthrographie, Radionuklidarthrographie und konventionellem Röntgen zur Erfassung von Prothesenlockerungen in der Knierevisionschirurgie

The value of plain radiographs, digital subtraction arthrography and radionuclide arthrography was analysed in 23 cases of failed total knee arthroplasty. The preoperative diagnosis was compared with the intraoperative assessment. Sensitivity, specificity and the positive and negative predictive value for assessing a loose component were determined separately for the femoral and tibial components. At revision we found 13 loose femoral and 12 loose tibial implants. In eight cases both components were unstable. Plain radiography had a sensitivity of 77% for loosening of the femoral and 83% for the tibial component; digital subtraction arthrography 77% for the femoral and 8% for the tibial component and radionuclide arthrography 31% and 8%. The specificity for plain radiography was 90% for the femoral and 72% for the tibial implant. For subtraction arthrography it was 50% and 82% and for subtraction arthrography 70% and 82%. Radiography had the highest positive and negative predictive values for both components compared with the other two techniques. As a diagnostic tool to detect implant loosening, plain radiography is the most effective in this study. Subtraction arthrography and radionuclide arthrography are not suitable for use as routine methods for detection of total knee arthroplasty loosening.