| Part I Bacteria16s rRNA,23s rRNA in interface membrane as a marker to detect periprosthetic infectionObjective:To explore the different power bwtween combining bacteria16s rRNA with23s rRNA and use them alone to diagnose periprosthetic joint infection (PJI).Methods:A prospective study of67patients who had a total hip arthroplasty (THA) and were undergoing a reoperation because of infection (23patients) or aseptic loosening (44patients) was conducted. The16S rRNA and23S rRNA in interface membrane were detected by realtime-PCR as a marker to diagnose PJI. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of different diagnosis algorithms (16s rRNA,23s rRNA,16s rRNA/23s rRNA and16s rRNA+23s rRNA) were compared.Results:There were no difference between using16s rRNA and23s rRNA to detect PJI. The sensitivity and negativ predictive value were higher if16s rRNA/23s rRNA were utilized to diagnose PJI than the algorithms of16s rRNA+23s rRNA, respectively (95.7%vs52.2%, P<0.01;97.6%vs79.6%, P=0.01). The specificity, positive predictive value, and accuracy of four diagnosis algorithms were not difference.Conclusions:The diagnosis power of16s rRNA and23s rRNA to detect PJI was similar.Compared with The algorithms of16s rRNA+23s rRNA, the algorithms of16s rRNA?/23s rRNA was more sensitive to detect PJIPart II Interleukin-6in serum and interface membrane diagnoses compare for periprosthetic joint infectionsObjective:To compare the power between Interleukin-6(IL-6) in serum and in interface membrane to detect periprosthetic joint infection.Methods:Total81cases were studied including52cases of aseptic loosening and29case for PJI, while10patients with chronic inflammatory diseases. The serum levels of IL-6were measured by enzyme linked immunosorbent assay (Elisa) and the infection was defined if serum IL-6>10pg/mL. Immunohistochemisty result of IL-6in interface membrane were used to discriminate aseptic loosening and PJI. The diagnosis power of IL-6in serum and interface membrane were calculated either patients with chronic inflammatory diseases were included or not. The mRNA expression and proten of IL-6were compared between normal cases and patients with chronic inflammatory diseases by real-time PCR and Western blot, respectively.Results:Serum IL-6as a marker, the specificity to detect PJI decreased from97.8%to84.6%(P=0.04) if patients with chronic inflammatory diseases were included. However, IL-6in interface membrane were utilized to diagnose PJI, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not change regardless of patients with chronic inflammatory diseases were included or not. The mRNA expression and proten of IL-6were similar between normal cases and patients with chronic inflammatory diseases (28.3vs42.8, P=0.06;38.5vs41.4, P=0.71,respectively)Conclusions:The diagnosis power of serum IL-6were prone to be influenced by chronic inflammatory diseases while IL-6in interface membrane were not. Chronic inflammatory diseases don’t affect the mRNA expression and proten of IL-6in interface membrane.PartⅢ Correlation between C-reactive protein, PGE2and pain in patients with aseptic loosening or periprosthetic joint infection after total hip arthroplastyObjective:To explore the difference in level of pain and pain characteristics by patients with THA between aseptic loosening and periprosthetic infection, and to examine the correlation between CRP, PGE2and pain level. The diagnosis power were calculated for pain characteristics as a algorithms to diagnose PJI,Methods:Fifty-one patients suffering aseptic loosening (31cases) or periprosthetic joint infection (20cases) after THA were included in this study. Both the visual analog scale (VAS) and Harris pain score were used to estimate the level of pain experienced. CRP levels in serum and PGE2in interface membrane were measured. The difference in assessment of pain by VAS and Harris pain score was compared between the two groups, and the correlation between CRP, PGE2and pain was analyzed. Pain characteristics were categorized and compared between two group. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for using pain characteristics to detect PJI.Results:The mean VAS in the aseptic loosening group was5.39compared with5.48in the PJI group; however, the difference was not statistically significant (P=0.85). The mean rank of Harris pain score was26.23in the aseptic loosening group and25.65in the PJI group, but again there was no significant difference (P=0.88). The mean CRP level in the PJI group (72.86mg/L) was obvious higher than that in the aseptic loosening group (6.53mg/L), and the difference was statistically significant (P<0.01). Interface membrane PGE2in PJI group was higher than in the aseptic loosening group.(1.77vs1.36, P<0.01).The VAS was related with the CRP level in the PJI group (r=0.87, P<0.01), and the correlation between Harris pain score and CRP level was conspicuous (r=0.92, P<0.01) in this group. However, those correlations were not evident in the aseptic loosening group (r=0.25, P=0.17; r=0.19, P=0.65). The VAS and Harris pain score were related with the interface membrane PGE2in the PJI group (r=0.98, P<0.01; r=0.99, P<0.01) but not in the aseptic loosening group (r=0.21, P=0.26; r=-0.25, P=0.17). The pain characteristics was different bwtween aseptic loosening group and PJI group (P<0.01). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were80.0%,83.4%,86.7%,76.2%, and82.3%for pain characteristics as a algorithms to diagnose PJI.Conclusion:There is no difference in perception of pain in patients after THA between those with aseptic loosening and those with PJI. However, it is reliable to make a initial diagnosis according to the characteristics of pain. The positive correlation between CRP, PGE2and pian exists in patients with PJI but not with aseptic loosening. |
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