Objective To investigate the efficiency of 16S rRNA Real-time reverse transcription PCR technique in the diagnosis of periprosthetic joint infection,and compare its sensitivity and specificity with conventional culture.Methods There were 43 revision cases from July 2013 to December 2015.Synovial fluid collected by puncture preoperatively,tissues from five different parts around the prosthesis collected intra-operatively were cultured by blood plate and BacT/Alert FN respectively.The 16S rRNA in interface membrane was detected by real-time reverse transcription PCR as a marker to diagnose PJI.At the same time,the synovial fluid was routinely bacterial cultured.We compared the sensitivity and specificity of two methods.Results There are 22 THAs and 21 TKAs respectively in 43 cases,23 cases diagnosed prosthetic joint infection and 20 cases diagnosed non prosthetic joint infection.The sensitivity of 16S rRNA Real-time reverse transcription PCR is higher than the conventional bacterial culture (78.2％ vs.47.8％).There was no difference in the specificity and PPV and NPV.For PCR in prosthetic joint infection group,Staphylococcus epidermidis in 5 cases,Staphylococcus aureus in 3 cases,streptococcus in 4 cases,E.coli in 2 cases,Staphylococcus lugdunensis,Pseudomonas aeruginosa,Staphylococcus haemolyticus and Mycoplasma in 1 case respectively.For culture in prosthetic joint infection group,Staphylococcus epidermidis in 5 cases,Staphylococcus aureus in 2 cases,Staphylococcus lugdunensis,Pseudomonas aeruginosa,Staphylococcus haemolyticus and E.coli in 1 case respectively.For non prosthetic joint infection group,PCR and culture are all negative.Conclusion The sensitivity of 16S rRNA Real-time reverse transcription PCR is higher than the conventional bacterial culture.

Objective:To explore the clinical outcomes of articulating spacers in the treatment of chronic knee periprosthetic joint infection (PJI).Methods:A retrospective study was conducted of the 38 patients who had undergone stage-two revision for chronic knee PJI from January 2014 to January 2020 at Department of Articular Surgery, The First Affiliated Hospital to Fujian Medical University. They were 8 men and 30 women, aged from 37 to 84 years (average, 66.2 years). The PJI was unilateral in all, affecting 19 left sides and 19 right sides. According to the kind of spacers used in the stage-one revision, they were divided into 3 groups: metal-polyethylene one (10 cases), metal-cement one (15 cases) and cement one (13 cases). In the stage-two revision following infection control, the spacers were removed for sonication and microbial culture. Infection control, range of motion (ROM), Knee Society Score (KSS), and complications were followed up.Results:The 38 patients were followed up for an average of 30.8 months (from 13 to 75 months). All patients underwent spacer implantation at stage-one revision and infection was controlled in 37 of them (97.4%, 37/38). After stage-one revision, metal-polyethylene, metal-cement and cement groups achieved 95.0°±11.3°, 92.9°±8.3° and 75.5°±11.9° in ROM, 79.4±6.1, 77.3±4.0 and 73.0±7.2 in clinical KSS and 67.5±11.8, 69.0±10.4 and 60.8±11.0 in functional KSS, showing significant improvements in the above indexes between preoperation and postoperation ( P<0.05). The ROMs for the metal-polyethylene and metal-cement groups were significantly better than for the cement group ( P<0.05). A total of 32 patients completed stage-two revision, with 7 in the metal-polyethylene group, 12 in the metal-cement group and 13 in the cement group. Respectively, ROMs after stage-two revision were 104.6°±9.8°, 98.5°±8.7° and 86.1°±8.9°, clinical KSSs 85.3±4.6, 82.7±4.3 and 78.0±4.8 and functional KSSs 78.6±6.9, 77.3±8.2 and 69.5±8.3 for the metal-polyethylene, metal-cement and cement groups, showing significant improvements after stage-one revision ( P<0.05). The postoperative sonication fluid culture showed negative results in all. Conclusions:Articulating spacers can effectively control knee PJI and improve the knee function during revision interval and after revision. Metal spacers may lead to a better range of motion than traditional cement ones.

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 explore whether MRI WARP sequence can provide clearer musculoskeletal images to guide the operation for patients with periprosthetic joint infection (PJI) by comparing MRI WARP sequence images with conventional sequence images.Methods:The data were analyzed retrospectively of 23 PJI patients who had been diagnosed and treated at Department of Orthopedics, The First Affiliated Hospital to Fujian Medical University from January 2020 to February 2021. They were 13 females and 10 males, with an average age of 62.8 years (from 32 to 88 years). According to the MRI sequences, they were divided into a WARP group ( n=14) subjected to MRI scanning by WARP sequence and a conventional group ( n=9) subjected to MRI scanning by conventional sequence. The gender, age, erythrocyte sedimentation rate (ESR) and C-reaction protein (CRP) were recorded for both groups. The signal-to-noise ratios were compared between the 2 sequences and 2 experts evaluated the clarity and surgical guidance of the images. Results:There was no significant difference in gender, age, CRP or ESR between the 2 groups, showing comparability ( P>0.05). The 2 experts showed consistency in evaluation of image sharpness and surgical guidance ( P<0.05). The WARP group was significantly better than the conventional group in image sharpness score [2.25(2.0, 2.6) versus 1.00 (0.5, 1.0)], surgical guidance score [2.00(1.5, 2.5) versus 0.50(0, 0.8)], and signal-to-noise ratio [47.28 (32.8, 74.3) versus 21.67(13.5, 31.4)] ( P<0.05). Conclusion:MRI WARP sequence can provide clearer musculoskeletal images than conventional MRI sequence to better guide the operation for PJI patients.

Objective To investigate the role of next generation sequencing technology in the detection of pathogenic bacteria in synovial fluid of prosthetic joint infection.Methods Nine samples of synovial fluid specimens of prosthetic joint infection patients with positive microbial culture from October,1 2016 to April 1,2017 were collected.Each specimen (200 μl) was used for next generation sequencing.Total DNA was extracted from synovial fluid samples.The collected DNA samples were amplified by PCR in the V4 region of 16S rDNA gene.The amplified products were sequenced using the Illumina Miseq platform,2× 250 bp double-end sequencing strategy.The sequencing results were compared with the SILVA database to analyze the types of bacteria and relative abundance in the DNA samples.A total of 200 μl sterile double-distilled deionized water was used as control.Results Nine cases of microbial culture positive prosthetic joint infection synovial fluid DNA samples were sequenced by 16S rDNA amplicon sequencing and yielded 3 132 415 high-quality reads and 3 752 operational taxonomic units (OTU).At the level of bacteria,a total of 9 different bacterial gates were detected on 9 DNA samples.At the level of bacteria,34 different bacteria were detected by 16S rDNA amplicon sequencing.Each DNA sample was detected by 16S rDNA amplicon sequencing and the bacterial genus was identical to that of laboratory culture.16S rDNA amplicon sequencing detected more species of bacteria [6(3,9.5)] than bacterial cultures [(1.0(1.0,1.0)].There was statistically significant difference in the number of bacteria detected in the same specimen between the 16S rDNA amplicon sequencing and the laboratory culture (Z=2.533,P=0.011).Among them,the dominant bacterial population (highest abundance) detected by 16S rDNA amplicon sequencing in four DNA samples was consistent with the results of laboratory culture.Conclusion In the prosthetic joint infection,the 16S rDNA amplicon sequencing technology can accurately detect pathogens that are consistent with the laboratory culture,and can detect other bacteria outside the laboratory culture.This technology can provide the basis for clinical diagnosis and antibiotic selection.

Objective:To analyze the clinical efficacy of two-stage total hip arthroplasty in the treatment of chronic septic hip arthritis.Methods:From January 2008 to March 2020, 17 patients with chronic septic hip arthritis (17 hips) received two-stage total hip arthroplasty at Department of Orthopaedic Surgery, The First Affiliated Hospital to of Fujian Medical University. They were 11 males and 6 females, with an average age of 54.5 years (from 19 to 77 years) and 9 left and 8 right hips affected. There were 10 cases of primary septic hip and 7 cases of secondary infection after hip surgery. Three patients had undergone debridement in other hospitals and one patient had developed a sinus tract. In the first stage operation, the diseased femoral head and neck were resected to implant an articulating spacer after thorough debridement; in the second stage operation, the spacer was removed to implant a uncemented artificial hip prosthesis in 16 cases or a cemented artificial hip prosthesis in one case. Recorded were the results of microbial culture, operation time, intraoperative blood loss, and therapeutic outcomes of the patients.Results:Pathogenic data were available in 13 patients and the culture was negative in 4. The pathogens were detected by metagenomic next-generation sequencing in 2 patients with culture negative. In the first stage operation, operation time averaged 140.6 min (from 90 to 176 min) and intraoperative blood loss 361.8 mL(from 100 to 1 000 mL); in the second stage operation, operation time averaged 130.3 min (from 91 to 166 min)and blood loss 291.2 mL(from 50 to 700 mL). The average interval between the first and the second stage operations was 115.0 days(from 66 to 227 d). During the interval, spacer fracture occurred in one case, spacer dislocation in one case and lower extremity deep venous thrombosis in one case. All the patients were followed up for 12 to 82 months (average, 36.7 months) after second stage operation. The inflammatory indexes decreased to normal in all the 17 patients and infection recurrence was observed in none of them.Conclusions:Two-stage total hip arthroplasty may result in a high rate of successful treatment of chronic septic hip arthritis. Specific use of sensitive antibiotics after identification of specific pathogenic microorganisms by multiple methods is the key to a successful treatment.

Objective:To investigate the value of metagenomic Next-Generation Sequencing (mNGS) in etiological diagnosis of osteoarticular nontuberculous mycobacterial (NTM) infection.Methods:From January 2014 to October 2019, 119 patients were definitely diagnosed as osteoarticular infection at Department of Bone Tumor & Joint Surgery, The First Affiliated Hospital to Fujian Medical University. All of them underwent conventional culture followed by mNGS to screen out those with NTM infection by the etiological testing. Optimized culture was conducted for NTM infections. Demographic data, and results of conventional culture, mNGS and optimized culture were recorded for patients with NTM infection.Results:mNGS showed that 12 of the 119 patients with osteoarticular infection (12/119, 10.1%) had NTM infection. They were 6 males and 6 females aged from 31 to 82 years(average, 51.1 years). There were 5 cases of slowly-growing mycobacterial type and 7 cases of rapidly-growing mycobacterial type. The positive rate of primary culture was only 16.7% (2/12) by the conventional culture, but increased to 66.7% (8/12) by the optimized culture. The positive rate of optimized culture was 100% (7/7) for the rapidly-growing mycobacterial type and 20% (1/5) for the slowly-growing mycobacterial type.Conclusion:As the positive rate of conventional culture is low for patients with osteoarticular NTM infection, mNGS is superior due to its advantage in accurate etiological diagnosis, especially for that of rapidly-growing mycobacterial type.

Objective: To investigate and compare the capability of metagenomic next-generation sequencing (mNGS) in detecting pathogens and diagnosing of periprosthetic joint infection (PJI) from synovial fluid and sonicate fluid of patients who underwent revision arthroplasty. Methods: Thirty-five consecutive patients who underwent revision arthroplasty from May 2018 to November 2018 were included prospectively. There were 22 males and 13 females, 11 hip revisions and 24 knee revisions. All the patients were divided into the PJI group and aseptic loosening (AL) group. Synovial fluid and sonicate fluid of the explanted prostheses were obtained for microbiological culture and mNGS tests. Periprosthetic tissues were only collected for culture. Synovial fluid of three patients undergoing primary arthroplasty been treated by sonication as the negative control group concurrently. Comparisons of microbiological results and diagnostic value from mNGS and culture tests were performed. Results: In the 13 culture-positive PJI patients, mNGS results of synovial fluid were positive in 12 cases, while culture and mNGS results were completely consistent at species level in 7 cases, consistent at the genus level in 1 case. mNGS results of sonicate fluid were positive in 13 cases, while culture and mNGS results were completely consistent at species level in 9 cases, consistent at the genus level in 1 case. In 7 culture-negative PJI patients, 6 cases had consistent mNGS results at species level both from synovial fluid and sonicate fluid, however, one case had positive mNGS result only from sonicate fluid. All culture results and mNGS results of synovial fluid were negative in all 15 AL patients, however, mNGS results of sonicate fluid was positive in 1 AL case. Cultures and mNGS results were negative in all three pairs of negative-control samples. In all 70 samples, mNGS detected 24 pathogens in sonicate fluids and 22 pathogens in synovial fluids. There was no significant difference in number of raw reads and human reads ratio between mNGS of sonicate fluid and synovial fluid. mNGS of sonicate fluid generated significantly higher number of microbial reads and of stringently mapped reads of pathogen in species-level than that of synovial fluids. There was no significant difference in diagnostic sensitivity of PJI between mNGS of sonicate fluids and synovial fluids (90.0% vs 100.0%). Both of them were significantly higher than that of culture of synovial fluid, periprosthetic tissues. Diagnostic sensitivity of sonicate fluid mNGS was not significantly higher than that in culture of sonicate fluid (65%). The specificities were similar among various microbiological testing methods. Conclusion mNGS of either synovial fluid or sonicate fluid from patients who underwent revision arthroplasty can be used to detect the presence of pathogens effectively and diagnose PJI accurately. mNGS can identify more pathogens and generate a higher number of pathogenic reads from sonicate fluids than synovial fluid. mNGS of synovial fluids has met the clinical diagnostic demands for most PJI patients. mNGS of sonicate fluid could be applied in some cases.