The Method And Result Analyses Of Pathogenic Bacteria Culture On Chronic Periprosthetic Joint Infection After Total Knee Arthroplasty And Total Hip Arthroplasty

Objective:To describe the methods of pathogenic bacteria culture on chronic periprosthetic joint infection after total knee arthroplasty (TKA) and total hip arthroplasty (THA) and to analyze the results of culture. Methods:The medical data of 23 patients with chronic periprosthetic joint infection after TKA or THA from September 2010 to March 2014 were reviewed.15 cases of TKA and 8 cases of THA were included in this study. There were 12 males and 11 females with the mean age of 62 (range from 32 to 79) and among them,9 patients with sinus. All patients discontinued antibiotic therapy for a minimum of 2 weeks before arthrocentesis, taking pathogenic bacteria culture and antimicrobial susceptibility test by using synovial fluid taken preoperatively and intraoperatively of revision. Common pathogenic bacteria culture and pathological biopsy were taken on tissues intraoperatively of revision. Culture-negative specimens were prolonged the period of incubation for fourteen days. Results:The overall culture-positive rate of all 23 patients for one week before revision was 30.4%(7/23), and the positive rate of culture-negative samples which prolonged for fourteen days was 39.1%(9/23). Possible reasons were analyzed as insufficiency of synovial fluid, bring-in of antibacterial substance and deficiency of incubation period. The overall culture-positive rate of patients for one week intraoperatively of revision was 60.9%(14/23), and the positive rate of culture-negative samples which prolonged for fourteen days was 82.6%(19/23). The incubation results of 7 cases (30.4%) preopratively conformed to that of intraoperation. Conclusion:The culture-positive rate of pathogenic bacteria culture can be increased evidently by discontinuing antimicrobial therapy for a minimum of two weeks prior to the definite diagnosis, strict aseptic processing of specimens, reasonable extension of the incubation period and close collaboration with microbial department. All of these can guide the clinical use of antibiotics and improve the control rate of infection after revision.