Abstract: Objective：To investigate the application value of nextgeneration sequencing technology in the detection of pathogenic bacteria in the joint fluid of delayed infection after knee arthroplasty.Methods：41 patients with joint infection after knee replacement in our hospital from February 2014 to March 2019 were selected.The bacteria in joint fluid were identified by nextgeneration sequencing technology and traditional bacterial culture.Then the detection rate of the two methods for different bacteria was calculated.Results：In the secondgeneration sequencing,31.71%,21.95%,24.39%,14.63%,17.07%,9.76% and 12.20% of the patients infected with grampositive Staphylococcus aureus,Staphylococcus epidermidis,Staphylococcus haemolyticus,human Staphylococcus,Streptococcus lactis,Streptococcus pyogenes and Streptococcus lactis were detected,moreover,19.51%,14.63%,4.88%,12.20% and 14.63% of the patients were  infected with gramnegative Pseudomonas aeruginosa,Escherichia coli,Haemophilus influenzae,Klebsiella pneumoniae and Acinetobacter baumannii.Bacterial culture found no Streptococcus lactis.No fungi were detected by the two methods.The detection rate of Staphylococcus aureus was 70.73%(13/41) by nextgeneration sequencing technology,which was higher than 12.20%(5/41) by traditional bacteria culture(P<0.05).The nextgeneration sequencing technology results showed that the average bacterial ACE index(12 834.06±317.52),Chao1 index(8 025.37±351.08),Simpson index(0.53±0.01) and Shannon index(5.06±0.11) in the samples of 41 patients were obtained.Conclusion：nextgeneration sequencing technology has a great advantage in the detection of bacteria in the joint fluid of infected patients after knee replacement,has good application prospect and value.

Key words: nextgeneration sequencing technology, knee arthroplasty, delayed infection, pathogenic bacteria