ObjectiveTo analyze the infection characteristics of human respiratory syncytial virus (HRSV) among children hospitalized with acute lower respiratory tract infection (ALRTI) in a specialized pediatric hospital in Shanghai, so as to provide evidence-based support for optimizing the prevention and control strategies and clinical diagnosis and treatment of respiratory tract infections in children in this region. MethodsA retrospective analysis was performed to the clinical and etiological data of 29 260 children hospitalized for ALRTI in Shanghai Children’s Hospital from January 2021 to December 2024. HRSV and 12 other common respiratory pathogens were detected with multiplex polymerase chain reaction (PCR) and capillary electrophoresis. Demographic and clinical data were collected for statistical analyses. A total of2 412 cases with positive HRSV were divided into the severe group and the non-severe group. Clinical characteristics between the two groups were compared using the Mann-Whitney U test and the chi- square (χ²) test. Additionally, the related influencing factors of severe HRSV infection were explored. ResultsThe overall positivity rate of HRSV from 2021 to 2024 was 8.24% (2 412/29 260), with statistically significant differences observed across the four years (χ²=389.42, P<0.001). The highest positivity rate was in 2021 (14.76%), with a high prevalence throughout the year. In 2022, when non-pharmaceutical interventions (NPIs) were implemented, the HRSV positivity rate was the lowest (4.93%), with a winter-dominant epidemic pattern. In 2023, after the NPIs were lifted, the HRSV positivity rate showed a slight rebound (8.14%), presenting a double-peak pattern. In 2024, the HRSV positivity rate slightly decreased compared to that in 2023 (6.29%), exhibiting a winter and spring-dominant epidemic pattern. Among the hospitalized children with ALRTI, the HRSV positivity rate in males (8.85%) was higher than that in females (7.51%), and the difference was statistically significant (χ²=17.33, P<0.001). Age distribution showed that 82.26% (1 984/2 412) of HRSV infections occurred in children aged 3 years old and below. Besides, as age increased, the infection rate of HRSV showed a gradually decreasing trend (P<0.001). Among the 2 412 children with HRSV infection, the proportion of severe cases was 22.31% (538/2 412), while the non-severe cases accounted for 77.69% (1 874/2 412). Compared with non-severe cases, severe cases were more frequently presented with high fever, longer duration of wheezing, as well as higher rates of underlying diseases or co-infection with Mycoplasma pneumoniae (P<0.001). ConclusionThe prevalence intensity of HRSV varied yearly from 2021 to 2024. After the removal of NPIs in 2023, a slight rebound with a double-peak epidemic pattern was observed. HRSV remained a common pathogen in children hospitalized for ARLTI, and children aged 3 years old and below constituted the highest proportion for infection. Compared with non-severe cases, those with severe HRSV infections were more prone to presenting with high fever and a longer duration of wheezing. Children with positive HRSV who had underlying diseases or co-infection with Mycoplasma pneumonia were more likely to develop severe conditions.

Objective:To investigate the clinical characteristics of children with severe human metapneumovirus (HMPV) infection and identify the risk factors associated with critical illness.Methods:A retrospective cohort study was conducted, enrolling 157 hospitalized children with severe HMPV infection, who tested positive for HMPV nucleic acid via PCR-capillary electrophoresis fragment analysis of nasopharyngeal secretions at Shanghai Children′s Hospital from January 2021 to December 2023.Clinical features, co-infections, treatment, and outcomes were collected. Based on the diagnostic criteria for severe HMPV infection, the patients were categorized into a critical illness group and a non-critical illness group. Intergroup comparisons were performed using the χ2 test or the Mann-Whitney U test. Multivariate Logistic regression analysis was employed to identify risk factors for critical HMPV infection and to establish a predictive model.The performance of the model was evaluated using receiver operating characteristic (ROC) curve analysis and calibration curves. Results:Among the 157 cases of severe HMPV infection, there were 67 males and 90 females, with an onset age of 39.0 (20.0, 55.5) months. Single-pathogen infection was observed in 125 cases (79.6%), while mixed infections accounted for 32 cases (20.4%).Severe pneumonia was diagnosed in 136 cases (86.6%).The predominant manifestations of severe HMPV infection included fever 152 cases (96.8%), cough 151 cases (96.2%), and wheezing 94 cases (59.9%).Sixty-eight patients (43.3%) required non-invasive respiratory support, 58 cases (36.9%) were admitted to the intensive care unit, and 22 cases (14.0%) underwent mechanical ventilation. Of the total, 149 cases (94.9%) were discharged with improvement, 8 cases (5.1%) were discharged against medical advice, and there were no fatal cases. The cohort was further stratified into a critical illness group 31 cases and a non-critical illness group 126 cases. Compared to the non-critical illness group, the critical illness group exhibited significantly higher rates of respiratory distress, lethargy, and intercostal retractions, along with a higher proportion of underlying comorbidities, and elevated levels of C-reactive protein and procalcitonin (all P<0.05).Conversely, albumin and hemoglobin levels were significantly lower in the critical illness group (both P<0.05). ROC curve analysis revealed that the optimal cutoff value for the duration of fever in predicting severe HMPV infection was 4.5 days.The multivariate binary Logistic regression analysis revealed that prolonged fever duration (>4.5 days) ( OR=28.00, 95% CI 5.09-153.93, P<0.001), anorexia ( OR=11.72, 95% CI 1.26-108.75, P=0.030), and immune dysfunction ( OR=36.71, 95% CI 1.55-867.31, P=0.026) were independent risk factors for severe HMPV infection. A predictive model for critical illness was constructed based on these independent risk factors. ROC curve analysis demonstrated excellent discriminative ability, with an area under the curve of 0.96 (95% CI 0.92-1.00, P<0.001). The optimal predictive probability threshold was 0.17, yielding a sensitivity of 0.93 and specificity of 0.92. The calibration curve closely approximated the ideal curve, indicating good model calibration ( P=0.157). Conclusions:Severe HMPV infection is predominantly observed as a single infection and is prone to progress to severe pneumonia, with fever, cough, and wheezing as the main clinical manifestations. A subset of cases progresses to critical illness, though the overall prognosis is favorable. Prolonged fever duration (>4.5 days), anorexia, and immune dysfunction were independent risk factors for critical illness.The risk prediction model constructed for pediatric critical HMPV infection demonstrated robust discriminative ability with excellent calibration.

Objective To investigate the ameliorative effect and potential mechanism of Cyclocaryae Paliuri Folium in sodium palmitate-induced lipid deposition in HepG2 cells.Methods The effect of sodium palmitate and lyophilized powder of Cyclocaryae Paliuri Folium on the viability of HepG2 cells was determined by the CCK-8 method to determine the subsequent dosage administered.The HepG2 cells were divided into blank group,model group,pioglitazone group and Cyclocaryae Paliuri Folium low-,medium-and high-dosage group,the lipid deposition model of HepG2 cells was established using 350 μmol/L sodium palmitate,the medication group were given pioglitazone and low-,medium-and high-dosage of Cyclocaryae Paliuri Folium(100,250,500 μg/mL)for 12 h respectively.The intracellular lipid deposition was observed by Nile red staining and BODIPY493/503 fluorescent probe staining,the content of TNF-α and IL-6 in supernatant of cell culture medium were detected by ELISA,Western blot was used to detect PI3K,Akt,sterol-regulatory element binding protein-1(SREBP-1),fatty acid synthase(FAS),Bcl-2,Bax protein expression,qPCR was used to detect the mRNA expression of adipose triglyceride lipase(ATGL)and CD36.Results Compared with the blank group,the lipid deposition of HepG2 cells in the model group increased,TNF-α and IL-6 contents in the supernatant of cell culture medium significantly increased(P<0.01),the protein expressions of p-PI3K,p-Akt,SREBP-1,FAS and Bax in cells significantly increased,while the protein expression of Bcl-2 significantly decreased(P<0.01),the mRNA expression of ATGL significantly decreased,and the mRNA expression of CD36 significantly increased(P<0.01).Compared with the model group,the intracellular lipid deposition of the pioglitazone group and Cyclocaryae Paliuri Folium groups improved to varying degrees,the contents of TNF-α and IL-6 in the cell supernatant decreased,the expressions of p-PI3K,p-Akt,SREBP-1,FAS and Bax proteins decreased,the expression of Bcl-2 protein increased,the expression of ATGL mRNA increased,and the expression of CD36 mRNA decreased,with statistical significance in pioglitazone group and Cyclocaryae Paliuri Folium high-dosage group(P<0.05,P<0.01).Conclusion Cyclocaryae Paliuri Folium may ameliorate sodium palmitate-induced lipid deposition in HepG2 model cells by modulating the PI3K/Akt/SREBP-1/FAS signaling pathway and affecting triacylglycerol metabolism.

BACKGROUND:The treatment of Pauwels type Ⅲ femoral neck fractures in young adults is extremely difficult.When treating Pauwels type Ⅲ femoral neck fractures with internal fixation,it is not only necessary to ensure the mechanical stability of the internal fixation,but also to ensure that it can resist the impact of shear,compression and tension,so as to prevent the internal fixation from breaking or loosening due to fatigue during the fracture healing process.However,existing internal fixation methods do not fully meet our requirements for the treatment of this fracture.OBJECTIVE:To provide a more reasonable and effective choice of internal fixation mode for clinicians in the treatment of young adults with Pauwels type Ⅲfemoral neck fracture,so as to optimize the treatment effect,reduce the occurrence of complications,and improve the recovery speed and quality of life of patients.METHODS:A femoral neck fracture model with Pauwels angle of 70° was constructed using CT data extracted from volunteers,and three placement modes were set up:(1)femoral neck system group:the main nail of femoral neck system was located in the center of the femoral neck axis.(2)Combination group:The main nail of femoral neck system was located in the lower third of the femoral neck axis,and a cannulated compression screw was located in the upper third of the femoral neck axis.(3)Cannulated compression screw group:The arrangement of three cannulated compression screws was arranged in the classic inverted triangle shape to ensure the maximum fixed effect.Stress distribution and displacement of proximal femoral fracture fragments and internal fixation devices were analyzed under three different internal fixation methods.RESULTS AND CONCLUSION:(1)The stress of the proximal femur models in the three groups was concentrated near the fracture line:combination group(201.10 MPa)＜femoral neck system group(222.25 MPa)＜cannulated compression screw group(271.25 MPa).(2)The peak value of proximal femur displacement was located at the top:combination group(6.33 mm)＜femoral neck system group(9.37 mm)＜cannulated compression screw group(9.92 mm).(3)The internal fixation stress was concentrated on the screw surface at the broken end of the fracture and gradually extended from there to both sides;cannulated compression screw group(136.67 MPa)＜combination group(201.10 MPa)＜femoral neck system group(222.25 MPa).(4)The maximum displacement of the internal fixation device model was located at the very top of the internal fixation.The three groups gradually decreased from the top to the far end.The peak displacement values of combination group(6.21 mm)＜femoral neck system group(9.19 mm)＜cannulated compression screw group(9.51 mm).(5)The stress of proximal bone mass in the three models was mainly concentrated in the fracture end,especially in the lower part of the fracture end.This indicates that these regions were subjected to greater stress and strain during mechanical transfer;combination group(24.96 MPa)＜femoral neck system group(39.69 MPa)＜cannulated compression screw group(44.47 MPa).(6)The results indicate that the internal fixation strategy of femoral neck system combined with cannulated compression screw arranged in parallel coronal surface shows higher biomechanical stability than single femoral neck system fixation or cannulated compression screw in inverted triangle arrangement fixation,and provides a more reliable and effective solution for the treatment of Pauwels type Ⅲ femoral neck fracture in young adults.

AIM: To investigate the changes in serum levels of trefoil factor 1(Tff1)and bone morphogenetic protein 4(BMP4)in patients with diabetic retinopathy, and to evaluate their diagnostic value for diabetic retinopathy.METHODS: From January 2022 to January 2024, 186 patients with type 2 diabetes were selected as the study group and divided into a retinopathy subgroup(52 cases)and a non-retinopathy subgroup(134 cases)based on the presence of retinopathy. Another 186 healthy volunteers who underwent physical examinations during the same period were chosen as the control group. Serum Tff1 and BMP4 levels were measured using the enzyme-linked immunosorbent assay(ELISA). Pearson analysis was used to assess the correlation between serum Tff1, BMP4 levels, and clinical data. Multivariate Logistic regression analysis was performed to identify factors influencing the development of retinopathy in type 2 diabetic patients. Receiver operating characteristic(ROC)curve analysis was conducted to evaluate the diagnostic value of serum Tff1 and BMP4 levels for retinopathy in type 2 diabetic patients.RESULTS: Compared to the control group, serum Tff1 levels were lower and BMP4 levels were higher in both retinopathy and non-retinopathy subgroups(all P<0.05). Specifically, serum Tff1 levels were lower and BMP4 levels were higher in the retinopathy subgroup than in the non-retinopathy subgroup(all P<0.05). Pearson analysis revealed that Tff1 levels in type 2 diabetes patients were negatively correlated with disease duration, glycated hemoglobin levels, and triglyceride levels, while BMP4 levels were positively correlated(all P<0.05). Multivariate Logistic regression analysis identified type 2 diabetes duration, glycated hemoglobin, triglycerides, Tff1, and BMP4 as influencing factors for retinopathy development in type 2 diabetes patients(all P<0.05). ROC curve analysis showed that the combined diagnosis of serum Tff1 and BMP4 had an area under the curve(AUC)of 0.901, which was significantly higher than that of Tff1 alone(Z=2.069, P=0.039)and BMP4 alone(Z=2.072, P=0.038).CONCLUSION: Serum Tff1 levels are decreased and BMP4 levels are increased in patients with diabetic retinopathy, and the combined detection of these two markers offers high diagnostic value for diabetic retinopathy.

BACKGROUND:The biomechanical stability of basal femoral neck fracture is poor,and the treatment plan is different from the traditional femoral neck fracture. At present,there is still no consensus on the surgical plan for the treatment of basal femoral neck fracture in young adults. OBJECTIVE:To compare the biomechanical characteristics of proximal femoral nail antirotation and femoral neck system in the treatment of basal femoral neck fractures by finite element analysis.METHODS:First,Mimics Medical 21.0 software was used to extract the right femur CT data of healthy young female volunteers to establish a preliminary model. Secondly,the model was imported into Geomagic Wrap 2021 software for further smoothing. SOLIDWORKS 2021 software was used to establish and assemble the femoral neck base fracture model,proximal femoral nail antirotation model,and femoral neck system model. Finally,the assembled model was imported into Workbench 2021 R1 software for biomechanical analysis.RESULTS AND CONCLUSION:(1) Stress distribution:the stress distribution of the proximal femoral nail antirotation group was mainly near the fracture line and the medial side of the femur,and the peak stress was 151.90 Mpa. In the femoral neck system group,the stress distribution of the femoral model was mainly near the fracture line,and the peak stress was 290.74 Mpa. The proximal femoral nail antirotation internal fixation stress was mainly distributed at the proximal end of the helical blade and the main nail,and the peak stress was 102.95 Mpa. The stress distribution of internal fixation in femoral neck system mainly extended to both sides of the support rod,and the peak stress was 184.69 Mpa. (2) Total displacement:the maximum displacement of the femoral model in the proximal femoral nail antirotation group was 4.0323 mm,and the maximum displacement of the femoral model in the femoral neck system group was 4.6489 mm. The maximum displacement was located in the femoral head. The peak displacement of internal fixation in the proximal femoral nail antirotation group and the femoral neck system group was 2.7094 mm and 3.1303 mm,respectively. The displacement of internal fixation in the two groups was mainly concentrated in the proximal end of internal fixation,and gradually decreased to the distal end. (3) It is concluded that in the femoral neck base fracture model,whether it is the femoral model or the internal fixation model,the proximal femoral nail antirotation group has more dispersed stress distribution,lower stress peak,smaller femoral head displacement,and better biomechanical stability than the femoral neck system group.

Objective:To analyze the distribution and epidemiological characteristics of non-bacterial pathogens in hospitalized children with acute respiratory infections at a tertiary pediatric hospital in Shanghai during 2023.Methods:A retrospective study was conducted on 10 591 children with acute respiratory tract infections who were hospitalized in Shanghai Children's Hospital from January to December 2023. A multiplex PCR combined with capillary electrophoresis platform was used to detect 11 common non-bacterial respiratory pathogens（including viruses and atypical pathogens）. Statistical analysis was carried out using SPSS 29.0 software. Qualitative data were presented as numbers and percentages，and the Chi-square test was employed to make comparisons between groups，aiming to analyze the differences in the distribution of different pathogens according to gender，age group，and season. Additionally，based on the severity of the disease，patients were calssified into a severe pneumonia group and a non-severe pneumonia group to further explore the characteristics of the pathogen spectrum of severe pneumonia.Results:The total detection rate of pathogens was 54.39%（5 760/10 591），and the proportion of mixed infections was 12.76%（735/5 760）. The dominant pathogens and their proportions were as follows： Mycoplasma pneumoniae（19.20%，2 034/10 591），human rhinovirus（12.16%，1 288/10 591），influenza A virus（8.31%，880/10 591），and respiratory syncytial virus（8.14%，862/10 591）. Epidemiological characteristics showed that：（1）In terms of age： Mycoplasma pneumoniae was more common in older children（29.55%，901/3 049，in the school-age group，χ 2 = 653.67， P<0.001）. Influenza A virus had a high incidence in the adolescent group（11.34%，45/397，χ 2=48.69， P<0.001）. Respiratory syncytial virus was most susceptible in the infant group（20.94%，280/1 337，χ 2=739.92， P<0.001）. Human rhinovirus showed the characteristic of general susceptibility across all ages.（2）Monthly and seasonal distribution： Mycoplasma pneumoniae had a seasonal epidemic in summer and autumn（it began to rise in May and peaked in October at 34.22%，439/1 283）；influenza A virus had a bimodal distribution in spring and winter（the peak was 37.15% in March，315/848）；respiratory syncytial virus had a dominant epidemic in spring and summer（the detection rate was 21.24% in May，206/970），and human rhinovirus was prevalent throughout the year.（3）Clinical correlation：The detection rate of pathogens in the severe pneumonia group was significantly higher than that in the non-severe group：84.19%（426/506） vs 2.89%（5 334/10 085），χ 2=56.23， P<0.001. Conclusions:In 2023，the pathogen spectrum of hospitalized children with acute respiratory infections in the Shanghai area exhibits an epidemic pattern dominated by Mycoplasma pneumoniae，and its transmission dynamics are significantly age-dependent. This study delineates the pathogen-host-environment tripartite interactions，establishing an evidence-based foundation for formulating precision diagnostic-therapeutic algorithms and seasonal nosocomial infection prevention frameworks.

Objective To investigate the ameliorative effect and potential mechanism of Cyclocaryae Paliuri Folium in sodium palmitate-induced lipid deposition in HepG2 cells.Methods The effect of sodium palmitate and lyophilized powder of Cyclocaryae Paliuri Folium on the viability of HepG2 cells was determined by the CCK-8 method to determine the subsequent dosage administered.The HepG2 cells were divided into blank group,model group,pioglitazone group and Cyclocaryae Paliuri Folium low-,medium-and high-dosage group,the lipid deposition model of HepG2 cells was established using 350 μmol/L sodium palmitate,the medication group were given pioglitazone and low-,medium-and high-dosage of Cyclocaryae Paliuri Folium(100,250,500 μg/mL)for 12 h respectively.The intracellular lipid deposition was observed by Nile red staining and BODIPY493/503 fluorescent probe staining,the content of TNF-α and IL-6 in supernatant of cell culture medium were detected by ELISA,Western blot was used to detect PI3K,Akt,sterol-regulatory element binding protein-1(SREBP-1),fatty acid synthase(FAS),Bcl-2,Bax protein expression,qPCR was used to detect the mRNA expression of adipose triglyceride lipase(ATGL)and CD36.Results Compared with the blank group,the lipid deposition of HepG2 cells in the model group increased,TNF-α and IL-6 contents in the supernatant of cell culture medium significantly increased(P<0.01),the protein expressions of p-PI3K,p-Akt,SREBP-1,FAS and Bax in cells significantly increased,while the protein expression of Bcl-2 significantly decreased(P<0.01),the mRNA expression of ATGL significantly decreased,and the mRNA expression of CD36 significantly increased(P<0.01).Compared with the model group,the intracellular lipid deposition of the pioglitazone group and Cyclocaryae Paliuri Folium groups improved to varying degrees,the contents of TNF-α and IL-6 in the cell supernatant decreased,the expressions of p-PI3K,p-Akt,SREBP-1,FAS and Bax proteins decreased,the expression of Bcl-2 protein increased,the expression of ATGL mRNA increased,and the expression of CD36 mRNA decreased,with statistical significance in pioglitazone group and Cyclocaryae Paliuri Folium high-dosage group(P<0.05,P<0.01).Conclusion Cyclocaryae Paliuri Folium may ameliorate sodium palmitate-induced lipid deposition in HepG2 model cells by modulating the PI3K/Akt/SREBP-1/FAS signaling pathway and affecting triacylglycerol metabolism.

BACKGROUND:The biomechanical stability of basal femoral neck fracture is poor,and the treatment plan is different from the traditional femoral neck fracture. At present,there is still no consensus on the surgical plan for the treatment of basal femoral neck fracture in young adults. OBJECTIVE:To compare the biomechanical characteristics of proximal femoral nail antirotation and femoral neck system in the treatment of basal femoral neck fractures by finite element analysis.METHODS:First,Mimics Medical 21.0 software was used to extract the right femur CT data of healthy young female volunteers to establish a preliminary model. Secondly,the model was imported into Geomagic Wrap 2021 software for further smoothing. SOLIDWORKS 2021 software was used to establish and assemble the femoral neck base fracture model,proximal femoral nail antirotation model,and femoral neck system model. Finally,the assembled model was imported into Workbench 2021 R1 software for biomechanical analysis.RESULTS AND CONCLUSION:(1) Stress distribution:the stress distribution of the proximal femoral nail antirotation group was mainly near the fracture line and the medial side of the femur,and the peak stress was 151.90 Mpa. In the femoral neck system group,the stress distribution of the femoral model was mainly near the fracture line,and the peak stress was 290.74 Mpa. The proximal femoral nail antirotation internal fixation stress was mainly distributed at the proximal end of the helical blade and the main nail,and the peak stress was 102.95 Mpa. The stress distribution of internal fixation in femoral neck system mainly extended to both sides of the support rod,and the peak stress was 184.69 Mpa. (2) Total displacement:the maximum displacement of the femoral model in the proximal femoral nail antirotation group was 4.0323 mm,and the maximum displacement of the femoral model in the femoral neck system group was 4.6489 mm. The maximum displacement was located in the femoral head. The peak displacement of internal fixation in the proximal femoral nail antirotation group and the femoral neck system group was 2.7094 mm and 3.1303 mm,respectively. The displacement of internal fixation in the two groups was mainly concentrated in the proximal end of internal fixation,and gradually decreased to the distal end. (3) It is concluded that in the femoral neck base fracture model,whether it is the femoral model or the internal fixation model,the proximal femoral nail antirotation group has more dispersed stress distribution,lower stress peak,smaller femoral head displacement,and better biomechanical stability than the femoral neck system group.

BACKGROUND:The treatment of Pauwels type Ⅲ femoral neck fractures in young adults is extremely difficult.When treating Pauwels type Ⅲ femoral neck fractures with internal fixation,it is not only necessary to ensure the mechanical stability of the internal fixation,but also to ensure that it can resist the impact of shear,compression and tension,so as to prevent the internal fixation from breaking or loosening due to fatigue during the fracture healing process.However,existing internal fixation methods do not fully meet our requirements for the treatment of this fracture.OBJECTIVE:To provide a more reasonable and effective choice of internal fixation mode for clinicians in the treatment of young adults with Pauwels type Ⅲfemoral neck fracture,so as to optimize the treatment effect,reduce the occurrence of complications,and improve the recovery speed and quality of life of patients.METHODS:A femoral neck fracture model with Pauwels angle of 70° was constructed using CT data extracted from volunteers,and three placement modes were set up:(1)femoral neck system group:the main nail of femoral neck system was located in the center of the femoral neck axis.(2)Combination group:The main nail of femoral neck system was located in the lower third of the femoral neck axis,and a cannulated compression screw was located in the upper third of the femoral neck axis.(3)Cannulated compression screw group:The arrangement of three cannulated compression screws was arranged in the classic inverted triangle shape to ensure the maximum fixed effect.Stress distribution and displacement of proximal femoral fracture fragments and internal fixation devices were analyzed under three different internal fixation methods.RESULTS AND CONCLUSION:(1)The stress of the proximal femur models in the three groups was concentrated near the fracture line:combination group(201.10 MPa)＜femoral neck system group(222.25 MPa)＜cannulated compression screw group(271.25 MPa).(2)The peak value of proximal femur displacement was located at the top:combination group(6.33 mm)＜femoral neck system group(9.37 mm)＜cannulated compression screw group(9.92 mm).(3)The internal fixation stress was concentrated on the screw surface at the broken end of the fracture and gradually extended from there to both sides;cannulated compression screw group(136.67 MPa)＜combination group(201.10 MPa)＜femoral neck system group(222.25 MPa).(4)The maximum displacement of the internal fixation device model was located at the very top of the internal fixation.The three groups gradually decreased from the top to the far end.The peak displacement values of combination group(6.21 mm)＜femoral neck system group(9.19 mm)＜cannulated compression screw group(9.51 mm).(5)The stress of proximal bone mass in the three models was mainly concentrated in the fracture end,especially in the lower part of the fracture end.This indicates that these regions were subjected to greater stress and strain during mechanical transfer;combination group(24.96 MPa)＜femoral neck system group(39.69 MPa)＜cannulated compression screw group(44.47 MPa).(6)The results indicate that the internal fixation strategy of femoral neck system combined with cannulated compression screw arranged in parallel coronal surface shows higher biomechanical stability than single femoral neck system fixation or cannulated compression screw in inverted triangle arrangement fixation,and provides a more reliable and effective solution for the treatment of Pauwels type Ⅲ femoral neck fracture in young adults.