Objective:To investigate whether the prophylactic use of a dose of sensitive antibiotics before revision for periprosthetic joint infection (PJI) may affect the positive rate of intraoperative specimen culture.Methods:This prospective study recruited the patients who underwent revision due to PJI from July 1, 2017 to February 1, 2019 at Department of Orthopaedics, The First Affiliated Hospital to Fujian Medical University. After use of antibiotics was stopped in all patients for 2 weeks before operation, synovial fluid was extracted for culture to confirm pathogenic bacteria and drug sensitivity and some/all of the prostheses were removed during operation. According to their sequence number of admission, the patients were randomly divided into group A and group B. Samples were taken in group A after a dose of sensitive antibiotics was administered 30 to 60 minutes before revision while a dose of sensitive antibiotics was given in group B after all samples were taken. Intra-operatively, synovial fluid, tissue grinding fluid (TGF) and ultrasonic prosthesis lysate (UPL) were taken for aerobic and anaerobic culture. According to whether there was a positive culture of at least one microbiological specimen, the preoperative and intraoperative culture results were analyzed and compared between the 2 groups.Results:A total of 32 PJI patients were included in this study due to positive culture of synovial fluid before operation, with 16 cases in group A and 16 in group B. The most common infection bacteria were staphylococci (59.3%, 19/32). There was no significant difference in age, gender, mode of operation, Tsukayama classification, prosthesis removal, preoperative ESR, CRP, synovial fluid white blood cell count (SF-WBC) or polymorphonuclear cell percentage (PMN) between the 2 groups. The positive rates of synovial fluid, tissue, TGF and UPL were 81.3% (13/16), 62.5% (10/16), 93.8% (15/16) and 93.8% (15/16) for group A, and 87.5% (14/16), 68.8% (11/16), 93.8% (15/16) and 100.0% (16/16) for group B, showing insignificant differences between the 2 groups ( P>0.05). The positive rates of TGF and UPL culture showed no significant difference between them in group A or in group B ( P>0.05), but they were significantly higher than those of traditional tissue culture ( P<0.05). Conclusions:As prophylactic use of antibiotics before PJI revision may not affect the positive rate of intraoperative specimen culture, it is not necessary to postpone use of prophylactic antibiotics before PJI revision. Furthermore, as positive rates of TGF and UPL culture are similar but significantly higher than those of traditional tissue culture, tissue grinding can be used to improve the positive rate of tissue culture.

Objective To construct the rheumatoid arthritis fibroblast-like synoviocytes(RAFLS)model,and to investigate the effects of usnic acid on the inflammatory pathway of high-mobility group protein B1(HMGB1)/receptor for activated glycation end products(RAGE)and the expression levels of vascular en-dothelial growth factor(VEGF),interleukin(IL)-6 and IL-1β.Methods The patients with RA undergoing joint replacement surgery in the orthopedic department of the Second Affiliated Hospital of Guizhou Universi-ty of Traditional Chinese Medicine were selected and the synovial tissues were obtained during operation.The cells were divided into the blank control group(fetal calf serum),solvent control group(fetal calf serum+10％hydroxypropyl betacyclodextrin),usnic acid high dose group(usnic acid 50 μg/mL),usnic acid middle dose group(usnic acid 10 μg/mL),usnic acid low dose group(usnic acid 2.5 μg/mL)and hydroxychloroquine group(hydroxychloroquine 50 mmol/L).The cell proliferation after different concentrations of usnic acid treatment was detected by MTT,the HMGB1 and RAGE protein expression in cells of each group was detec-ted by Western blot,and the expression levels of HMGB1,VEGF,IL-6 and IL-1β were detected by ELISA.Re-sults Compared with the blank control group,the proportions of cellular apoptosis in the usnic acid high,middle and low doses groups and hydroxychloroquine group were increased(P＜0.05);the expression levels of HMGB1 and RAGE protein in the usnic acid high,middle and low doses groups and hydroxychloroquine group were significantly decreased(P＜0.05),the expression levels of HMGB1,VEGF,IL-6 and IL-1β were decreased(P＜0.05);compared with the hydroxychloroquine group,the cellular apoptosis proportions of the usnic acid high,middle and low doses groups were decreased(P＜0.05),the HMGB1 protein expression level in the usnic acid low dose group was significantly increased(P＜005),the RAGE protein expression level in the the usnic acid middle amd low doses groups was significantly increased(P＜0.05).Conclusion Usnic acid alleviates the inflammatory reaction of synoviocytes possibly by regulating HMGB1/RAGE inflammatory pathway and VEGF,IL-6 and IL-1β inflammatory factors expression levels.