Femoral neck fracture (FNF) in the elderly patients is currently a major health challenge worldwide, with excessive consumption of medical resources, high incidence of complications as well as suboptimal outcome and prognosis. Hip joint arthroplasty (HJA) has been the mainstream treatment for FNF in the elderly, but the conventional surgical approaches and techniques are still confronted with a series of bottlenecks such as dislocation, limp and limb length discrepancy. In recent years, direct anterior approach (DAA) for HJA (DAA-HJA) has been a major new choice in the field of joint replacement, which achieves improved clinical effectiveness of HJA in the treatment of elderly FNF, due to the fact that DAA approach involves the neuromuscular interface and accords with the idea of soft tissue retention and enhanced recovery after surgery. However, there is still a lack of unified understanding of standard technique and procedure of DAA-HJA in the treatment of elderly FNF. Therefore, relevant experts from the Hip Joint Group of Chinese Orthopedics Association of Chinese Medical Association, Youth Arthrology Group of Orthopedic Committee of PLA, Orthopedic Committee of Chongqing Medical Association, Branch of Orthopedic Surgeons of Chongqing Medical Doctor Association and Sport Medicine Committee of Chongqing Medical Association were organized to formulate the " Chinese expert consensus on the technical standard of direct anterior hip arthroplasty for elderly femoral neck fracture ( version 2023)" based on evidence-based medicine. This consensus mainly proposed 13 recommendations covering indications, surgical plans, prosthesis selections, surgical techniques and processes, and postoperative management of DAA-HJA in elderly patients with FNF, aiming to promote standardized, systematic and patient-specific diagnosis and treatment to improve the functional prognosis of the patients.

Objective:To investigate the changes and clinical significance of white blood cell (WBC) count and polymorphonuclear cells (PMN) proportion of synovial fluid after primary total knee arthroplasty (TKA).Methods:A total of 59 patients (92 knees) who underwent TKA from April 2021 to July 2021 were included, including 13 males (20 knees) and 46 females (72 knees). The patients were with average age 65.17±7.49 years old (range 48-79) and with body mass index (BMI) 27.64±3.74 kg/m 2 (range 17-36 kg/m 2). There were 26 cases involved lateral knee and 33 cases bilateral knees. The left knee was involved in 46 knees, while other 46 were involved in right side. There were 54 patients diagnosed as osteoarthritis (84 knees) and 5 as rheumatoid arthritis (8 knees). None of the patients received antibiotics after hospitalization. Antibiotics were used prophylactically 30 min before surgery and after surgery. The synovial fluid WBC count and PMN proportion were detected during operation (It reflects the normal preoperative level) and on the 2nd, 5th and 35th day after operation. The changes of these indexes were analyzed. The unmixed synovial fluid was collected after the incision of the joint capsule during the operation. The outer upper edge of the patella was taken as the puncture point to extract the synovial fluid on the 2nd, 5th and 35th days after the operation. The final follow-up end point was a diagnosis of acute periprothetic joint infection (PJI) or 90 days of follow-up for patients without PJI. Results:After operation, the synovial fluid WBC count and PMN proportion showed a trend of increasing and then decreasing. The synovial fluid WBC count were 0.222(0.100, 0.567)×10 9/L, 20.011(14.573, 29.129)×10 9/L, 6.080(3.676, 8.797)×10 9/L, 0.533(0.394, 0.749)×10 9/L before surgery and at 2nd, 5th and 35th day after surgery respectively. The difference before and after operation was statistically significant (χ 2=247.343, P<0.001). The synovial fluid PMN proportion were 19.9%(15.0%, 30.0%), 96.0%(95.0%, 97.0%), 91.0%(89.0%, 93.0%) and 20.5%(15.6%, 26.9%) respectively and with significant difference (χ 2=242.521, P<0.001). Pairwise comparison of synovial fluid WBC count and PMN proportion before and on day 35 indicated no statistical significance ( P>0.05). However, the differences compared with that at other time points were statistically significant ( P<0.05). Conclusion:The synovial fluid WBC count and PMN proportion increased rapidly in the short term after TKA and then decreased to the preoperative level at varied rates. Referring to the Musculoskeletal Infection Society (MSIS) recommended threshold for diagnosing infection during the acute stress period (within 5 d postoperatively) can result in false positives. Recovery to preoperative levels at 35th days postoperatively can be used as a basis for ruling out early infection. Thus, early joint fluid PMN proportion may have more diagnostic value than WBC counts.

Objective:To obtain purified protein antigen of guertu virus (GTV) nucleoprotein (NP) and establish a rapid and accurate enzyme-linked immunosorbent assay (ELISA) method for detection of GTV antibody.Methods:Codon optimized GTV NP encoding genes were synthesized, cloned into the pet32a (+) vector, and recombinant expression plasmids were constructed and transformed into BL21 (DE3). Recombinant protein (rNP) obtained from the optimized expression were purified over a Ni column and identified by SDS-PAGE and Western blot. The purified protein was used as the antigen to optimize the reaction conditions, and an indirect ELISA assay for GTV IgG antibody was developed and optimized, which was evaluated and initially applied.Results:The prokaryotic expression plasmid pet32a-NP was successfully constructed, the recombinant protein was highly expressed in E. coli in the form of inclusion bodies, the size was about 44 kD, and the results of Western blot indicated that the recombinant protein had good antigenicity with GTV positive serum. The optimized ELISA (GTV-rNP-iELISA) established in this study showed strong specificity, high sensitivity, and the coefficient of variation within and between batches is less than 10%, and has good repeatability; the detection results are consistent with the IFA detection results. Using the established ELISA method to detect 162 sheep sera from some regions of Xinjiang in 2017-2019, the total positive rate of antibodies was 39.8%.Conclusions:The GTV NP antibody detection ELISA method has good sensitivity, reproducibility, and specificity and has the potential to be a powerful tool for the diagnosis and serological investigation of GTV infection.

Objective:To obtain purified protein antigen of guertu virus (GTV) nucleoprotein (NP) and establish a rapid and accurate enzyme-linked immunosorbent assay (ELISA) method for detection of GTV antibody.Methods:Codon optimized GTV NP encoding genes were synthesized, cloned into the pet32a (+) vector, and recombinant expression plasmids were constructed and transformed into BL21 (DE3). Recombinant protein (rNP) obtained from the optimized expression were purified over a Ni column and identified by SDS-PAGE and Western blot. The purified protein was used as the antigen to optimize the reaction conditions, and an indirect ELISA assay for GTV IgG antibody was developed and optimized, which was evaluated and initially applied.Results:The prokaryotic expression plasmid pet32a-NP was successfully constructed, the recombinant protein was highly expressed in E. coli in the form of inclusion bodies, the size was about 44 kD, and the results of Western blot indicated that the recombinant protein had good antigenicity with GTV positive serum. The optimized ELISA (GTV-rNP-iELISA) established in this study showed strong specificity, high sensitivity, and the coefficient of variation within and between batches is less than 10%, and has good repeatability; the detection results are consistent with the IFA detection results. Using the established ELISA method to detect 162 sheep sera from some regions of Xinjiang in 2017-2019, the total positive rate of antibodies was 39.8%.Conclusions:The GTV NP antibody detection ELISA method has good sensitivity, reproducibility, and specificity and has the potential to be a powerful tool for the diagnosis and serological investigation of GTV infection.

Objective:To study whether early leukocytosis after total joint arthroplasty (TJA) requires further workup to exclude infection by observing changes in peripheral blood white blood cell (WBC) count after TJA.Methods:This study included the 294 patients (infection-free group) who had undergone primary hip or knee TJA from June 2019 to June 2020 but reported no periprosthetic joint infection (PJI) within one month after surgery and the 31 patients (infection group) who had undergone the same TJA but reported infection within one month after surgery from May 2012 to June 2020 at Department of Joint Surgery, The First Affiliated Hospital to Xinjiang Medical University. Peripheral blood WBC counts were measured and recorded before surgery and 1 to 5 days after surgery. Differences were compared between time points and multiple linear regression analysis was used to screen the factors associated with early postoperative leukocytosis. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of WBC for early PJI.Results:The peripheral WBC level in the infection-free group showed a trend of increasing at first and then decreasing. It reached the peak on day 2 after surgery, increasing by 8.08×10 9/L±2.33×10 9/L compared to pre-surgery, and then began to decrease to a level slightly higher than the preoperative value on day 5 after surgery. The changes in WBC count in the first 2 days after surgery ranged from 6.24×10 9/L to 26.32×10 9/L. The incidence of leukocytosis in the first 5 days after surgery was 95.6% (281/294). The factors associated with postoperative leukocytosis included preoperative WBC count and bilateral surgery. For every increase of 1.00×10 9/L in preoperative WBC count, the postoperative WBC value increased by an average of 0.98×10 9/L [ β=0.984, 95% confidence interval (95% CI): 0.821-1.148, P<0.001]. The postoperative WBC count in the patients undergoing bilateral surgery increased by an average of 1.03×10 9/L compared with that in the patients undergoing unilateral surgery ( β=1.026, 95% CI: 0.565-1.486, P<0.001). The area under the curve (AUC) for prediction of early PJI by absolute WBC count difference (the absolute difference between the maximum postoperative WBC value and the baseline) was 0.655 (95% CI: 0.546-0.764, P<0.05), providing a threshold of 7.96×10 9/L, a sensitivity of 57.5% and a specificity of 74.2%. Conclusions:Leukocytosis is a common phenomenon after TJA, indicating a normal physiological response to surgery. The preoperative WBC count is a predictor for postoperative leukocytosis. In the absence of abnormal clinical symptoms or signs, there is no need for further workup to check infection if the postoperative WBC does not deviate from its changing range and trend.

Objective:To investigate the relevant factors on serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) which did not meet the 2011 Musculoskeletal Infection Society (MSIS) diagnostic criteria in patients with periprosthetic joint infection (PJI).Methods:During December 2011 to December 2019, a total of 328 patients with PJI were hospitalized for surgery or antibiotic administration, including 152 males and 166 females, aged 62.10±13.74 (range 24-87) years. All patients underwent CRP and ESR before the antibiotic administration or the revision surgery. PJI was diagnosed based on the 2011 MSIS diagnostic criteria. There were 172 knee PJIs (52.4%), 151 hip PJIs (46.0%), 4 elbow PJIs (1.2%) and 1 shoulder PJI (0.3%). Patients were classified according to Tsukayama type, pathogen and immune status. We, further, analyzed relevant factors on CRP and ESR levels in PJI patients.Results:There were 119 patients with CRP and ESR did not meet the MSIS diagnostic criteria, accounting for 36.3% (119/328). Furthermore, there was no significant difference in Tsukayama types among them (χ 2=7.224, P=0.065). In addition, the ratio was 46.4% in patients with negative culture results, which was higher than that in positive culture results (27.4%, χ 2=12.276, P<0.001). The ratio was 42.9% in patients with normal immune status (grade A), which was higher than that of immune grade B (30.6%) and of immune grade C (23.8%) (χ 2=6.586, P=0.037). Multivariate logistic regression analysis showed the negative association between positive culture results and immune grade B with nonconformity ( OR=0.420, P=0.001; OR=0.578, P=0.04). Conclusion:The serum tests level unmet the threshold in MSIS criteria usually present in PJI patients with normal immune status and negative culture results. Thus, we should utilize other methods for diagnosing PJI.

Objective:To analyze the pathogen distribution and drug resistance in acute,delayed and chronic periprosthetic joint infection (PJI).Methods:The clinical data of 316 patients with periprosthetic infection after primary hip and knee arthroplasty admitted to the Department of Arthroplasty,the First Affiliated Hospital,Xinjiang Medical University from August 2010 to August 2020 were retrospectively analyzed.There were 146 males and 170 females,aged (62.3±14.2) years (range:22 to 89 years).One hundred and sixty one patients underwent total hip arthroplasty and 155 patients underwent total knee arthroplasty.According to the time of postoperative infection,the patients were divided into acute PJI group (65 cases),delayed PJI group (83 cases) and chronic PJI group (168 cases).The results of pathogen species,composition ratio and drug susceptibility tests were collected,and the independent sample t test,Chi-square test or Fisher′s exact probability test were used for comparison. Results:Gram-positive bacteria were the main pathogens of PJI (49.7%,157/316),and the positive rates of culture in patients with acute PJI,delayed PJI and chronic PJI were 33.8% (22/65),55.4% (46/83) and 53.0% (89/168),and the difference was statistically significant(χ2=8.343, P=0.015).The common bacteria were coagulase-negative Staphylococcus (54.8%,86/157) and Staphylococcus aureus (30.6%,48/157),The drug-sensitivity to linezolid,vancomycin and tigacycline was 100%.The gram-negative bacteria were mainly Escherichia coli and Enterobacter cloacae,and the drug resistance rate to carbapenems was low,ranging from 0 to 9.09%.The drug resistance rates of acute PJI patients to rifampicin,ciprofloxacin and erythromycin were significantly higher than those of late onset and chronic PJI patients,the difference was statistically significant(rifampicin:χ2=14.332, P=0.001;ciprofloxacin:χ2=12.086, P=0.002;erythromycin:χ2=9.096, P=0.010);The drug resistance rate of acute PJI patients to levofloxacin,clindamycin and tetracycline was higher than that of chronic PJI patients,and the difference was statistically significant(levofloxacin:χ2=10.500, P=0.002; clindamycin: χ2=7.103, P=0.007; tetracycline: χ2=6.909, P =0.012).The resistance rate of ampicillin/sulbactam in acute PJI (60.0%) was significantly higher than that in chronic PJI (16.7%),and the difference was statistically significant(χ2= 5.853, P=0.040). Conclusion:Gram-positive bacteria are the main pathogens of PJI,and the resistance rate of pathogens of acute PJI is higher than that of late onset and chronic PJI.

Objective:To analyze the pathogen distribution and drug resistance in acute,delayed and chronic periprosthetic joint infection (PJI).Methods:The clinical data of 316 patients with periprosthetic infection after primary hip and knee arthroplasty admitted to the Department of Arthroplasty,the First Affiliated Hospital,Xinjiang Medical University from August 2010 to August 2020 were retrospectively analyzed.There were 146 males and 170 females,aged (62.3±14.2) years (range:22 to 89 years).One hundred and sixty one patients underwent total hip arthroplasty and 155 patients underwent total knee arthroplasty.According to the time of postoperative infection,the patients were divided into acute PJI group (65 cases),delayed PJI group (83 cases) and chronic PJI group (168 cases).The results of pathogen species,composition ratio and drug susceptibility tests were collected,and the independent sample t test,Chi-square test or Fisher′s exact probability test were used for comparison. Results:Gram-positive bacteria were the main pathogens of PJI (49.7%,157/316),and the positive rates of culture in patients with acute PJI,delayed PJI and chronic PJI were 33.8% (22/65),55.4% (46/83) and 53.0% (89/168),and the difference was statistically significant(χ2=8.343, P=0.015).The common bacteria were coagulase-negative Staphylococcus (54.8%,86/157) and Staphylococcus aureus (30.6%,48/157),The drug-sensitivity to linezolid,vancomycin and tigacycline was 100%.The gram-negative bacteria were mainly Escherichia coli and Enterobacter cloacae,and the drug resistance rate to carbapenems was low,ranging from 0 to 9.09%.The drug resistance rates of acute PJI patients to rifampicin,ciprofloxacin and erythromycin were significantly higher than those of late onset and chronic PJI patients,the difference was statistically significant(rifampicin:χ2=14.332, P=0.001;ciprofloxacin:χ2=12.086, P=0.002;erythromycin:χ2=9.096, P=0.010);The drug resistance rate of acute PJI patients to levofloxacin,clindamycin and tetracycline was higher than that of chronic PJI patients,and the difference was statistically significant(levofloxacin:χ2=10.500, P=0.002; clindamycin: χ2=7.103, P=0.007; tetracycline: χ2=6.909, P =0.012).The resistance rate of ampicillin/sulbactam in acute PJI (60.0%) was significantly higher than that in chronic PJI (16.7%),and the difference was statistically significant(χ2= 5.853, P=0.040). Conclusion:Gram-positive bacteria are the main pathogens of PJI,and the resistance rate of pathogens of acute PJI is higher than that of late onset and chronic PJI.

Objective To present clinical effects of debridement, antibiotics, irrigation and retention of implant (DAIR) with integrated antibiotics application in treating periprosthetic joint infection (PJI) occurred within 3 months after primary surgery. Methods We retrospectively analyzed patients who received DAIR between January 2011 and October 2015. A total of 49 pa?tients with a mean age of 62.38±14.56 years (range, 26-82 years) were included in this study, including 29 males and 20 females. There are 27 knees and 22 hips. Twenty?three patients has sinus tract. Failure was defined as subsequent surgical intervention for infection after the index procedure; persistent fistula, drainage, or excessive joint pain at the last follow?up; death related to the PJI; chronic suppression with antibiotics. Results There were 18 (36.7%) culture negative cases and 31 (63.3%) culture positive cases, including 28.6% (14/49) methicillin?sensitive staphylococcus aureus, 4% (2/49) methicillin?resistant staphylococcus aure?us, 2% (1/49) methicillin?resistant staphylococcus epidermidis, 2%(1/49) mixed infection with fungus and so on. Within the 68.34± 14.02 months (range, 39-94 months) follow?up duration, the Knee Society Score (KSS) score was improved from 38.37 ± 12.39 points (range, 18-62 points) pre?operatively to 82.26±10.50 points (range, 49-96 points) post?operatively (t=-17.09, P<0.001). KSS function score was improved from 42.19±10.14 points (range, 26-67 points) pre?operatively to 75.22±11.60 points (range, 41-90 points) post?operatively (t=-12.53, P<0.001). Harris hip score was improved from 47.41±8.39 points (range, 32-58 points) pre?operatively to 86.41±6.07 points (range, 71-96 points) post?operatively (t=-23.38, P<0.001). There were 6 patients receiving sub?sequent surgical intervention as failure. The mean duration from the index surgery to failure was 5.75±3.00 months (range, 1.5-10 months). Conclusion The present protocol of DAIR for dealing with early?stage PJI, which is less than 3 months after primary TKA or THA, is fairly effective.

Objective To establish a mouse model of pneumonia with C57BL/6 and MyD88KO mice after infection with an isolated ST23 Klebsiella pneumonia (KP) strain, which was an epidemic strain and identified by multilocus sequence typing (MLST). Methods Fifty C57BL/6 mice were randomly di-vided into three groups:KP infection,control and immunosuppressive groups. Thirty MyD88KO mice were divided into KP infection and control groups. All mice in the KP infection groups were infected with 50 μl of ST23 KP strain through nasal dripping. Equal volume of PBS was used to set up the control groups. Mice in the immunosuppressive group were first injected with cyclophosphamide for three days and then infected with equal volume of ST23 KP strains through nasal dripping. Clinical signs and survival curves during KP infec-tion were monitored. Moreover,pulmonary bacterial loads and histopathological changes in the KP-infected mice were detected at different time points. Results ST23 KP-infected C57BL/6 mice showed inflammatory cell infiltration in lung tissues on the 10th day and remained alive on the 21st day. All ST23 KP-infected MyD88KO mice died on the 5th day with severe histopathological damage in lung tissues. C57BL/6 mice that pretreated with cyclophosphamide had similar symptoms with MyD88KO mice after infection and died on the 5th day. Some critical inflammatory mediators such as TNF-a,nitric oxide synthase 1 (NOS1) and NF-κBp65 were up-regulated in lung tissues of mice after KP infection. No inflammatory syndromes were found in the mice of PBS control groups. Conclusion This study suggests that the mouse model of pneumonia is successfully established with KP strain. It will help researchers to study the characteristics and pathogenesis of ST23 KP strain-induced pneumonia and to seek safe treatments in the future.