BACKGROUND:In recent years,tranexamic acid has been extensively used to mitigate the substantial blood loss associated with total knee arthroplasty.However,the optimal method of topical application has not yet been established. OBJECTIVE:To evaluate the effectiveness and safety of intraoperative topical application of tranexamic acid combined with physical compression dressing in reducing perioperative blood loss in total knee arthroplasty. METHODS:A retrospective analysis was conducted on 90 patients who underwent total knee arthroplasty at the Honghui Hospital in Xi'an from January 2021 to December 2022.Based on the different topical use methods of tranexamic acid during surgery,patients were divided into three groups,with 30 cases in each group.In the compression dressing group,2 g of tranexamic acid was placed in the articular cavity,and after packing the wound with gauze and cotton pads,a bandage was used to compress the wound.In the periarticular injection group,2 g of tranexamic acid was injected into the surrounding tissue of the articular cavity.In the intra-articular injection group,2 g of tranexamic acid was injected into the articular cavity.The blood loss,operation time,coagulation indicators,inflammatory indicators,and postoperative complications of the three groups were statistically analyzed. RESULTS AND CONCLUSION:(1)In terms of total blood loss,hidden blood loss,and maximum hemoglobin drop,the periarticular injection group had the least amount,and there was no statistically significant difference between the compression dressing group and periarticular injection group(P>0.05).In terms of intraoperative blood loss,the compression dressing group had the least amount,and there were statistically significant differences compared with the periarticular injection group and intra-articular injection group(P<0.05).There was no statistically significant difference in operation time among the three groups(P>0.05).(2)There were no statistically significant differences in coagulation indicators(D-dimer and fibrinogen degradation products)and inflammation indicators(C-reactive protein and erythrocyte sedimentation rate)among the three groups preoperatively and on the first and third days after operation(P>0.05).(3)There was no statistically significant difference observed among the three groups in terms of slow blood flow in the affected limb,intramuscular venous thrombosis,soft tissue swelling,and incidence of wound complications(P>0.05).Additionally,no cases of deep vein thrombosis or pulmonary embolism were detected in any of the groups.(4)The topical application of tranexamic acid combined with compression dressing achieves the same effect as a periarticular injection in terms of simplicity of operation and reduced perioperative blood loss.This method also avoids the trauma caused by repeated punctures and does not increase the incidence of postoperative complications,making it a worthwhile option for clinical promotion.

Objective:To evaluate the mechanical performance of customized metal prosthesis with tibia stems of varying lengths for tibial bone defects reconstruction.Methods:Morphologically matched postoperative finite element models of bone defect revision were developed, with three gradients (15 mm, 30 mm, and 45 mm) according to the degree of bone defect and were reconstructed with 3D printed tantalum metal prosthesis using three tibial stem lengths (80 mm, 120 mm, and 150 mm), respectively. Conventional static and dynamic (walking gait) loading was performed to analyze the peak tibial stress distribution and accumulated sliding distance at the prosthetic interface, and to assess the effects of the three tibial stems of different lengths on the stability of the customized tibial defect restorations and the internal tibial stress state.Results:The peak accumulated sliding distance of the dynamically loaded morphologically matched restorations ranged from 17.94 to 21.31 mm with static loading, which were 68% to 84.3% higher than those of 10.26 to 11.69 mm with static loading. The peak tibial stresses in the dynamically loaded model were greater than those in the statically loaded model, with an increase of 28%-49.2%, including 132.94-143.88 MPa in the statically loaded model and 170.41-200.14 MPa in the dynamically loaded model. The overall accumulated sliding distance of the tibia prosthetic model gradually decreased from the tibial osteotomy surface, and the accumulated peak sliding distances ranged from 10.26 to 11.69 mm for static loading, and from 17.94 to 21.31 mm for dynamic loading. The bone tissue stresses in the anterolateral and medial-posterior tibia increased gradually from top to bottom, and the maximum stress value in each section was in the posterior medial tibia (the maximum value was 200.14 MPa). The highest bone tissue stress in the lateral tibia was affected by the tibial stem length, which resulted in a different location, and it was the area most affected by stress shielding (maximum value of 170.65 MPa).Conclusion:For stability assessment of morphologically matched tantalum customized prosthesis, physiological gait dynamic loading studies are more reliable than static loading; the choice of tibial stem length depends on a combination of accumulated peak sliding distances and tibial bone stress distribution factors.

Objective:To explore the application value of Oxford nanopore technologies (ONT) in the diagnosis and treatment of periprosthetic joint infection (PJI).Methods:A prospective analysis was conducted on 32 patients with PJI admitted to the joint department of Xi'an Honghui Hospital from October 2021 to March 2023, who met the 2018 PJI diagnostic criteria of the American Skeletal Infection Society (MSIS), including 15 males and 17 females with an average age of 63.93±8.93 years. 32 revision patients who did not meet the 2018 MSIS PJI criteria during the same period were collected as controls (non PJI group), including 13 males and 19 females with an average age of 65.53±8.54 years. All patients underwent joint fluid puncture before or during surgery, and the specimens were tested by ONT, metagenomic next generation sequencing (mNGS), and general microbial culture. The receiver operating characteristic (ROC) curves were drawn for both groups, and the sensitivity, specificity, positive predictive value, negative predictive value, and Youden index of the three detection techniques were calculated and compared to evaluate the detection efficiency of different detection methods in PJI.Results:Among the 32 patients with PJI, 30 were positive for ONT, with a total of 30 pathogenic bacteria detected, and the detection time was 22.37±8.36 h. 31 were positive for mNGS, with a total of 33 bacterial species detected, and the detection time was 46.25±9.36 h. 17 were positive for microbial culture, with a total of 8 bacterial species detected, and the detection time was 96.23±15.62 h. Among the 32 patients with non PJI group, 1 was positive for ONT and 5 were positive for mNGS, with a total of 1 and 3 bacterial species detected, respectively. The results of microbial culture were all negative. The detection time and area under the curve (AUC) of ONT and mNGS were 22.37±8.36 h and 0.953[95% CI (0.901, 1.006)], 46.25±9.36 h and 0.906[95% CI (0.835, 0.977)], respectively, which were better than those of microbial culture 96.23±15.62 h and 0.766[95% CI (0.678, 0.853)], and the difference was statistically significant ( P<0.05). The sensitivity of ONT, mNGS, and microbial culture were 0.938, 0.969, and 0.531, respectively, and the specificity was 0.969, 0.844, and 1.000, respectively. The Jordan index was 0.906, 0.813, and 0.531, respectively. Conclusion:ONT testing has higher diagnostic efficacy than mNGS and microbial culture in the diagnosis of PJI, and also has advantages in detection time. It also suggests that some PJI are not caused by a single microbial infection.

Objective To investigate serum levels of soluble apoptosis-related factor ligand(sFasL)and stromal cell derived factor 1(SDF-1)in patients with aplastic anemia(AA)and their correlation with immunosuppressive treatment.Methods Forty-three AA patients who received immunosuppressive therapy for half a year were selected as the observation group,and another 43 healthy subjects at the same period were selected as the control group.Patients in the observation group received immunosuppressive therapy and hematopoietic propoietic therapy,and patients were divided into the ineffective group and the effective group according to the efficacy.Clinical data of patients were collected,and serum levels of sFasL,SDF-1,tumor necrosis factor-α(TNF-α)and interleukin-8(IL-8)were detected by enzyme-linked immunosorbent assay.The correlation between serum sFasL and SDF-1 levels was analyzed.Multivariate Logistic regression analysis was conducted to analyze influencing factors of immunosuppressive treatment in AA patients.The predictive values of serum sFasL and SDF-1 on immunosuppressive treatment were analyzed by receiver operating characteristic(ROC)curve.Results Serum levels of sFasL and SDF-1 were higher in the observation group than those in the control group(P＜0.05).Serum levels of TNF-α,IL-8,sFasL and SDF-1 were higher in the ineffective group than those in the effective group(P＜0.05).Serum sFasL level was positively correlated with SDF-1 level in AA patients(r=0.534,P＜0.001).Increased serum sFasL and SDF-1 levels were independent risk factors for ineffective immunosuppressive therapy in AA patients(P＜0.05).The area under the curve(AUC)of serum sFasL and SDF-1 combined to predict the immunosuppressive treatment effect of AA patients was 0.973(95%CI:0.872-0.999),which was better than that of single diagnosis(P＜0.05),and its sensitivity and specificity were 94.44%and 96.00%,respectively.Conclusion Serum levels of sFasL and SDF-1 are significantly increased in patients with AA.The combined detection of sFasL and SDF-1 has high predictive value for the immunosuppressive treatment effect of AA.

Objective To assess the diagnostic efficacy of extracellular volume fraction(fECV)based on multi-slice spiral CT in evaluating lymph node metastasis of pancreatic ductal adenocarcinoma.Methods A total of 74 patients diagnosed as pancreatic ductal adenocarcinoma from March 2018 to March 2023 in the First Hospital of Jiaxing were retrospectively collected.All patients underwent enhanced multi-slice spiral CT examination.Hematocrit was collected before examination.CT values at the plain phase,portal phase,the equilibrium phase of the lesion and CT values of abdominal aorta at the same level were respectively measured after examination,and fECV was calculated.Using postoperative pathological results as the"gold standard",the efficacy of fECV in diagnosing lymph node metastases of pancreatic ductal adenocarcinoma was evaluated by receiver operating characteristic curve.Results There were 33 cases with lymph node metastasis in positive group and 41 cases in negative group.There was no statistically significant difference in fECV at the portal phase between lymph node metastasis positive group and negative group(t=0.80,P＞0.05).There was statistically significant difference in fECV at the equilibrium phase between positive and negative lymph node metastasis group(t=2.84,P＜0.001).The area under the curve of lymph node metastasis in portal phase and equilibrium phase were 0.517 and 0.870,respectively.Conclusion The fECV based on multi-slice spiral CT equilibrium phase can evaluate lymph node metastasis of pancreatic ductal adenocarcinoma.

Objective To analyze the plantar pressure distribution of knee osteoarthritis ( KOA) patients after medial opening wedge high tibial osteotomy ( MOWHTO), so as to provide biomechanical references for the surgical treatment and rehabilitation of patients. Methods A total of 31 patients with medial single compartmental KOA after unilateral MOWHTO treatment were selected as the experimental group, and 35 healthy subjects at same age were selected as the control group. The Pedomedic 40 􀅺 pressure measuring system was used to test dynamic plantar pressure. By comparing the maximum pressure ( pmax ), force-time integral ( FTI) and contact area (CA) of different plantar zones between the experimental group (operative side and unoperated side) and the control group during walking, the changes of plantar pressure in patients with medial single compartmental KOA after MOWHTO were evaluated. Results Compared with the unoperated side and the control group, the CA and FTI of the 1st metatarsal head (MH1) were higher (P<0. 05), the CA of the 4th metatarsal head (MH4)was smaller (P<0. 001), the pmax and FTI of the 5th metatarsal head (MH5) were smaller (P<0. 05), the CA of the lateral middle foot (MF-L) was smaller (P<0. 001), and the CA of the medial rear foot (RF-M) was larger (P<0. 05). Compared with the control group, the pmax of MH1 and MH2 was smaller (P<0. 05), the CA and FTI of MH5 were larger (P<0. 05), the pmax of MF-L was larger (P<0. 001), and the FTI of lateral rear foot (RF-L) was larger (P<0. 05). Conclusions Compared with healthy people, patients with medial single compartmental KOA have abnormal plantar pressure residual after MOWHTO. In clinical practice, targeted intensive rehabilitation therapy is necessary to restore the normal plantar distributions of patients.

Objective:To investigate the effect of fat mass index (FMI) on early recovery after total knee arthroplasty (TKA).Methods:Patients who underwent primary unilateral TKA in Xi'an Honghui Hospital from July 2020 to July 2021 were retrospectively analyzed. The preoperative body composition was measured by dual energy X-ray absorptiometry and the FMI was calculated. Patients were divided into normal group (male: 3.0-6.0 kg/m 2; female: 5.0-9.0 kg/m 2), overweight group (male: 6.1-9.0 kg/m 2; female: 9.1-13.0 kg/m 2), and obese group (male: >9 kg/m 2; female: >13 kg/m 2) according to level of FMI, and the operation time, blood loss, and incidence of postoperative complications were collected. Multifactorial analysis of the effect of FMI on early recovery after TKA was performed using a generalized linear model. Draw the receiver operating characteristics (ROC) curve of BMI and FMI on the predicted effect of postoperative Western Ontario and McMaster Universities (WOMAC) osteoarthritis index scores and Knee Society Score (KSS) to compare the effect of FMI with BMI on early recovery after TKA. Results:A total of 100 patients were included in the study, 24 males and 76 females, aged 65.0±8.2 years (range, 42-81 years). There were 15 cases in normal group, 55 cases in overweight group and 30 cases in obese group. All patients successfully completed the operation and were followed up for 3.15±0.72 months (range, 2.8-3.2 months). The WOMAC scores of the obese group at 2 weeks, 1 and 2 months postoperative were 34.57±3.68, 22.03±2.79, and 15.77±2.96, which were greater than those of the normal group (28.73 ±2.58, 19.07±2.71, 12.27±3.10), as well as the overweight group (30.05±4.09, 19.33±2.42, 14.84±2.42), with statistically significant differences ( P<0.05). The KSS scores of the obese group at postoperative 1 and 2 months were 68.83±5.52 and 81.17±4.49, which were lower than those of the normal group (77.33±5.63, 87.33±4.17), as well as the overweight group (72.64±5.43, 83.73 ±5.02), with statistically significant differences ( P<0.05). The WOMAC score, KSS score, and postoperative complications at 2 months postoperatively were selected as outcome indicators to plot the ROC curve, and the ROC curve for the WOMAC score at 2 months postoperatively showed an area under the curve corresponding to FMI of 0.744 (95% CI: 0.54, 0.82), which was greater than that of BMI [0.624 (95% CI: 0.51, 0.74)], and the difference was statistically significant ( Z=2.19, P=0.021). The ROC curve for the KSS score at 2 months postoperatively showed an area under the curve corresponding to FMI of 0.718 (95% CI: 0.62, 0.82), which was greater than that of BMI [0.612 (95% CI: 0.52, 0.74)], with a statistically significant difference ( Z=2.58, P=0.016). The ROC curve for postoperative complications showed an area under the curve of 0.639 (95% CI: 0.41, 0.88) for FMI and 0.605 (95% CI: 0.37, 0.84) for BMI, with no statistically significant difference ( Z=0.48, P=0.632). Conclusion:The greater the FMI the poorer the early functional recovery after initial TKA, and FMI is more valuable than BMI in predicting the early functional recovery.

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 compare the clinical effect of buttress plate fixation and cannulated screw fixation of Regan-Morrey type II ulnar coronoid fractures.Methods:A retrospective case control study was made on 53 patients with Regan-Morrey type II ulnar coronoid fractures admitted to Wuxi No.9 People 's Hospital from April 2015 to January 2018，including 36 males and 17 females，aged from 21 to 63 years［（36.3±7.1）years］. Among them，24 patients were treated using buttress plates（plate group），and 29 patients using cannulated screws（screw group）. The operation time and fracture healing time were documented. The visual analogue score（VAS），range of motion of elbow flexion and extension and forearm rotation and Mayo elbow performance score（MEPS）were assessed at postoperative 1，3，6 months and at the last follow-up. The incidence of complications was observed as well. Results:All patients were followed up for 15-18 months［（15.9±1.3）months］. The operation time in plate group［（150.6±24.2）minutes］was longer than that in screw group［（126.8±18.3）minutes］（ P<0.05）. There was no significant difference in fracture healing time or VAS between the two groups（ P>0.05）. After 1，3，6 months and during the last follow-up，the range of motion of elbow joint flexion and extension in plate group［（87.2±5.8）°，（109.2±7.1）°，（121.3±6.2）°，（127.3±5.4）°］was higher than that in screw group［（70.5±9.1）°，（90.2±4.5）°，（108.3±5.1）°，（116.2±4.6）°］，the range of motion of forearm rotation in plate group［（78.3±9.1）°，（98.7±8.6）°，（130.2±7.1）°，（139.2±6.7）°］was higher than that in screw group［（60.1±5.1）°，（80.6±8.7）°，（116.1±5.5）°，（127.3±4.1）°］，and the MEPS in plate group［（30.6±7.6）points，（68.1±6.1）points，（90.2±4.3）points，（95.2±2.1）points］was higher than that in screw group［（27.2±8.1）points，（54.1±7.1）points，（82.1±5.3）points，（88.2±5.2）points］（all P<0.05）. In plate group，one patient sustained superficial wound infection at postoperative 1 week，which was healed uneventfully after surgical debridement and antibiotic therapy；two patients had heterotopic ossification without addition surgery. In screw group，three patients presented screw loosening and fracture redisplacement during early movement，which was healed by reducing the intensity of elbow functional exercise and prolonging the protection time of brace；four patients had heterotopic ossification，among which one combined with elbow stiffness showed improved range of motion of the elbow after elbow release at postoperative 12 months. The incidence of complications in plate group［13%（3/24）］was lower than that in screw group［26%（7/29）］（ P<0.05）. Conclusion:For Regan-Morrey type II ulnar coronoid fractures，the buttress plate fixation is superior to the cannulated screw fixation in fixation strength，recovery of elbow function and incidence of complications in regardless of longer operation time.

Objective:To construct the pET30a-EgG1Y162-2 prokaryotic expression plasmid and induce the expression of EgG1Y162-2 protein, so as to provide a research basis for development of Echinococcus granulosus vaccine. Methods:Using Echinococcus granulosus cDNA as a template, the target gene of EgG1Y162-2 was synthesized by PCR, and after digestion with restriction enzymes EcoRⅠ and Hind Ⅲ, it was connected to the prokaryotic expression vector pET30a to construct the recombinant plasmid pET30a-EgG1Y162-2. The recombinant plasmid was transformed into competent cell BL21 (DE3) and induced by isopropyl β-D-thiogalactoside (IPTG) to express a large number of proteins. The recombinant protein was purified by affinity chromatography. The purification level was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and the expression product was identified by Western blotting. Results:The recombinant plasmid pET30a-EgG1Y162-2 was successfully constructed. After inducting expression, the bacterial supernatant and the eluate were both at a relative molecular weight of about 15 × 10 3, and the protein antigen component eluted with 200 mmol/L imidazole was relatively pure. Western blotting results showed that the purified recombinant protein EgG1Y162-2 with His tag could be recognized by His monoclonal antibody. Conclusion:The pET30a-EgG1Y162-2 prokaryotic expression plasmid of Echinococcus granulosus is successfully constructed, and the recombinant protein of EgG1Y162-2 is induced to express, laying a foundation for further study on anti- Echinococcus granulosus vaccine.