Objective: To discuss the epidemiological characteristics of hand foot mouth disease (HFMD) among children in Jiujiang City, and its correlation with meteorological factors, so as to provide scientific evidence for developing targeted HFMD prevention and control measures. Methods: HFMD incidence data among children and meteorological factor records from Jiujiang City during 2019-2023 were collected. Pearson correlation analysis and Quasi-Poisson regression analysis of generalized additive model were used to analyze the relationship between the number of cases and meteorological factors, calculating correlation coefficients (r) and excess risk (ER). Results: The annual reported children HFMD cases in Jiujiang City during 2019-2023 were 4 299, 4 671, 2 560, 3 230, and 3 584, respectively. Except for a peak in autumn-winter in 2020, outbreaks occurred mainly in spring and summer in other years. The majority of cases involved scattered children (71.11%) and children in daycare centers (26.64%). Pearson correlation analysis showed that total case counts, cases among scattered children, and cases among children in daycare centers were positively correlated with average temperature ( r =0.36, 0.39, 0.23), maximum temperature ( r =0.32, 0.36, 0.20), minimum temperature ( r =0.37, 0.41, 0.24), and average relative humidity ( r =0.19, 0.20, 0.15) (all P <0.05). Quasi-Poisson regression analysis of generalized additive model revealed that total cases, cases among scattered children, and cases among daycare children were positively associated with average temperature ( r =0.05, 0.06, 0.03) and average relative humidity ( r =0.03, 0.02, 0.02) (all P <0.01). Excess incidence risk analysis indicated that for every 10 ℃ increase in average temperature, the ER (95% CI ) values were 72.16 (45.91-103.14), 79.76 (52.99- 111.23 ) and 39.30 (14.45-69.54) among total children, scattered children and daycare children, respectively; for every 10% increase in average relative humidity, the ER (95% CI ) values were 28.69 (12.22-47.56), 27.81 (12.01-45.84) and 24.42 (5.56-46.65), respectively. Conclusions The incidence level of HFMD among children in Jiujiang City is positively correlated with the average temperature and average relative humidity. Higher temperature and humidity are associated with an increased risk of excess HFMD incidence in scattered children compared to children in daycare centers.

Background: Influenza A virus (IAV) is a negative-sense RNA virus of the Orthomyxoviridae family and is the etiological agent of a highly contagious acute respiratory disease that can lead to acute lung injury. Objective: To elucidate the molecular mechanisms of IAV infection, an integrative research approach combining gene expression profiling, multinetwork analysis, and in vivo experimental validations was employed. Methods: First, a series of network-based analyses were performed, including protein-protein interaction network construction, weighted gene co-expression network analysis, and subsequent gene set enrichment analysis, to identify the major underlying mechanisms of IAV infection. Following gene expression analysis, core targets, both direct and indirect regulators, were screened. An IAV (H1N1) strain A/PR/8/34-induced acute lung injury mouse model was constructed for in vivo validations. Batch one included two groups to evaluate findings from the multi-network analysis: Mock (n = 10; 5 males and 5 females) and IAV (n = 10; 5 males and 5 females). Batch two included three groups to assess the role of toll-like receptor 3 (TLR3) in IAV infection: Mock (n = 6; 3 males and 3 females), IAV (n = 6; 3 males and 3 females), and TLR3 inhibitor (n = 6; 3 males and 3 females). Body weight was measured on days 0, 3, and 5 after infection. On day 5, lung tissues were collected to assess viral load and histopathological changes. Key targets were examined using enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence staining, both in sera and lung tissues. Results: IAV infection was significantly associated with dysregulation of the immune-inflammation system, such as the LTR, nucle-otide-binding oligomerization domain-(NOD) like receptor, retinoic acid-inducible gene I-like receptor, and nuclear factor kappa-B signaling pathways. Gene set enrichment analysis further indicated that the TLR and necroptosis signaling pathways played crucial roles in the progression of IAV infection (TLR signaling pathway normalized enrichment score = 2.3941, P = 1.00 × 10 ⁻¹⁰; necroptosis normalized enrichment score = 1.9421, P = 6.21 × 10 ⁻⁷). Among the core targets, TLR3 and mixed lineage kinase domain-like protein (MLKL) may regulate gene expression at the transcriptional level (all P < 0.05). In vivo validation using an IAV (PR8) infected acute lung injury mouse model demonstrated increased viral load and lung index, alveolar structural damage, and inflammatory cell infiltration. Immunofluorescence staining exhibited large gaps in Lamin B1 staining and breaches in Emerin signals following IAV-PR8 infection. Expression levels of TLR3, p-receptor-interacting serine/threonine-protein kinase 3 (RIPK3)/RIPK3, and p-mixed lineage kinase domain-like protein (MLKL)/MLKL proteins in lung tissues, as well as proinflammatory factors and mediators in sera, were significantly elevated after IAV infection. Moreover, enhanced neutrophil infiltration (myeloperoxidase) and citrullinated histone H3 (a neutrophil extracellular trap-specific marker), both established indicators of neutrophil extracellular trap formation, were observed. Notably, treatment with a TLR3 inhibitor significantly ameliorated IAV-induced acute lung injury by regulating necroptosis-related targets. Conclusion: Our study provides network-based in vivo evidence that TLR3-receptor-interacting serine/threonine-protein kinase 3-MLKL-mediated necroptosis may underlie IAV-induced acute lung injury and could serve as a potential therapeutic target in severe influenza cases.

Objective To investigate the development, role, and regulatory mechanism of macrophage efferocytosis in the liver of hosts infected with Schistosoma japonicum. Methods The expression of efferocytosis-related gene like efferocytosis receptors, efferocytosis-related bridging molecules,“eat me” signal and “don’t eat me” signal was detected in the livers of patients and mice infected with S. japonicum in the Gene Expression Omnibus (GEO) database. Ten wild-type (WT) male mice (6 ~ 8 weeks old, weighing 20 ~ 25 g) were randomly divided into a Schistosoma japonicum infection (SJ) group and a normal control (NC) group, with 5 mice in each group. The efferocytosis of neutrophils and T cells by liver macrophages was detected in mice from SJ group and NC group using flow cytometry and immunofluorescence assay, respectively. The expression of efferocytosis-related Mer receptor tyrosine kinase (MerTK) and Axl receptor tyrosine kinase (Axl) proteins was determined in mouse liver tissues using Western blotting assay, and the proportion of MerTK⁺ macrophages and the average fluorescence intensity of macrophage MerTK were detected in mouse livers using flow cytometry. Changes in liver granulomas and fibrosis were observed in mice infected with S. japonicum following injection of efferocytosis inhibitors, and S. japonicum-infected mice without injection of efferocytosis inhibitors served as controls. Bone marrow-derived macrophages (BMDMs) were isolated from macrophage scavenger receptor class A (SR-A) conditional knockout (CKO) and wild-type (WT) mice, and changes in apoptotic neutrophils were detected in SR-A CKO mouse macrophages in vitro using flow cytometry. Then, BMDMs was divided into the WT mono-culture group, the WT and apoptotic neutrophils co-culture group, the SR-A CKO mono-culture group, and the SR-A CKO and neutrophils co-culture group, and the expression of MerTK and Axl was quantified in vitro using Western blotting and real-time quantitative PCR (RT-qPCR) assays during neutrophil efferocytosis. The efferocytosis of neutrophils and T cells by mouse liver macrophages was detected in the SR-A CKO SJ group and the WT SJ group using flow cytometry and immunofluorescence assay, and the expression of MerTK and Axl proteins was determined in mouse liver tissues in both groups using Western blotting. In addition, the proportion of MerTK⁺ macrophages and the average fluorescence intensity of macrophage MerTK were detected in mouse livers in both groups using flow cytometry. Results Data from the GEO database showed that the expression of some efferocytosis receptors and efferocytosis-related bridging molecules, and “eat me” and “don’t eat me” signals all appeared a tendency towards a rise in livers of patients and mice in the SJ group relative to the NC group, suggesting that S. japonicum infection-induced liver diseases may be associated with efferocytosis. Flow cytometry detected higher proportions of Ly6G⁺ cells [(13.13 ± 0.45)% vs. (6.48 ± 0.25)%; t = 22.30, P < 0.05] and CD3⁺ cells [(7.60 ± 0.33)% vs. (3.30 ± 0.42)%; t = 13.98, P < 0.05] in mouse liver macrophages in the SJ group than in the NJ group, and the expression of MerTK protein [(2.30 ± 0.14) vs. (1.14 ± 0.46); t = 4.19, P < 0.05], the mean fluorescence intensity of macrophages [(160.67 ± 15.28) vs. (94.50 ± 19.61); t = 4.81, P < 0.05], and the proportion of MerTK⁺ macrophages [(20.78 ± 4.17)% vs. (6.85 ± 0.39)%; t = 6.57, P < 0.05] were significantly higher in mouse liver tissues in the SJ group than in the NC group. The Axl expression was lower in mouse liver tissues in the SJ group than in the NC group [(1.25 ± 0.08) vs. (1.93 ± 0.37); t = 2.79, P < 0.05], and the area of granulomas around single eggs [(9.18 ± 1.81) × 10⁴μm² vs. (5.24 ± 1.35) × 10⁴ μm²; t = 3.03, P < 0.05] and proportion of collagen fibers [(25.27 ± 3.99)% vs. (15.14 ± 4.02)%; t = 3.10, P < 0.05] were significantly greater in livers of S. japonicum-infected mice with injection of efferocytosis inhibitors than in mice without injection of efferocytosis inhibitors. The in vitro efferocytosis efficiency of BMDMs [(32.83 ± 3.17)% vs. (45.43 ± 2.34)%; t = 5.54, P < 0.05], and the proportions of Ly6G⁺ [(9.37 ± 0.48)% vs. (13.13 ± 0.72)%; t = 7.50, P < 0.05] and CD3⁺ cells [(4.95 ± 0.17)% vs. (7.64 ± 0.50)%; t = 8.87, P < 0.05] in liver macrophages post-infection with S. japonicum were significantly lower in SR-A CKO mice than in WT mice, and the expression of MerTK protein [(0.65 ± 0.25) vs. (1.96 ± 0.69); t = 3.10, P < 0.05], the average fluorescence intensity of macrophages [(138.33 ± 8.39) vs. (160.67 ± 15.28); t = 3.03, P < 0.05] and the proportion of MerTK⁺ macrophages [(13.17 ± 5.01)% vs. (22.63 ± 2.06)%; t = 3.56, P < 0.05] were significantly lower in mouse liver tissues in the SR-A CKO SJ group than in the WT group. Western blotting detected no significant difference in the Axl protein expression in mouse liver tissues between the SR-A CKO SJ group and the WT SJ group [(0.48 ± 0.07) vs. (0.68 ± 0.30); t = 1.09, P > 0.05]. There were significant differences in the relative MerTK mRNA and protein expression during efferocytosis of BMDMs among the WT monoculture group, the WT and apoptotic neutrophils co-culture group, the SR-A CKO mono-culture group, and the SR-A CKO and neutrophils co-culture group (F = 9.41 and 40.68, both P values < 0.05). In addition, there was a significant difference in the relative Axl mRNA expression during efferocytosis of BMDMs among the four groups (F = 13.62, P < 0.05); however, no significant difference was seen in the relative Axl protein expression (F = 1.27, P > 0.05). Conclusions Efferocytosis of liver macrophages is seen in mice infected with S. japonicum and inhibits liver fibrosis. SR-A may up-regulate the efficiency of macrophage efferocytosis through regulating the expression of efferocytosis receptors.

ObjectiveTo investigate the association between perioperative troponin elevation and the occurrence of major adverse cardiac events （MACE） in elderly patients with colorectal cancer， and to provide evidence for optimizing perioperative management strategies. MethodsA total of 268 elderly patients aged 70 years and above who underwent colorectal cancer surgery were retrospectively enrolled. They were divided into a conventional management group （87 cases） and a standardized management group （181 cases） according to the perioperative management strategy. Binary logistic regression analysis was used to identify the independent influencing factors for the occurrence of major adverse cardiac events. P-value ≤ 0.05 was considered statistically significant. ResultsAmong the 268 patients， the overall incidence of perioperative major adverse cardiac events was 4.5% （12/268）. The total incidence of major adverse cardiac events in the conventional management group was 8.0% （7/87）， which was significantly higher than that in the standardized management group （2.8%， 5/181；P=0.05）. Specifically， the incidences of myocardial infarction， heart failure， and death in the conventional management group were markedly higher than those in the standardized management group （8.0% vs. 2.2%， 4.6% vs. 0.6%， 4.6% vs. 0.6%， all P＜0.05）， while no significant difference was observed in the incidence of cardiogenic shock between the two groups （1.1% vs. 1.1%， P＞0.05）. Postoperative troponin elevation was significantly associated with the occurrence of perioperative major adverse cardiac events except for cardiogenic shock （including total cardiovascular events， myocardial infarction， heart failure， and death） （all P＜0.05）， and it was identified as a strong independent risk factor for perioperative major adverse cardiac events in these patients. ConclusionCompared with conventional management， standardized perioperative troponin management can significantly reduce the risks of myocardial infarction， heart failure， and death， and also exhibits a potential protective trend against cardiogenic shock. Postoperative troponin elevation is a strong independent risk factor for the occurrence of perioperative major adverse cardiac events.

Objective Jejunal interposition is an important option for restoring gastrointestinal continuity in patients with complex esophageal cancer in whom the stomach is unavailable for reconstruction due to previous gastrectomy, tumor involvement, failed gastric conduit, or other constraints. Although the jejunum offers a caliber similar to the esophagus, a rich blood supply, and preserved peristaltic function, anatomical variations in mesenteric length and vascular arcades render long-segment and high-level reconstruction susceptible to excessive tension, mesenteric torsion, venous congestion, and inadequate distal perfusion. This consensus aims to provide standardized recommendations for the application of jejunal interposition in this specific patient population. Methods This consensus was developed in accordance with the WHO Handbook for Guideline Development and Chinese national guideline development standards, with reference to the Appraisal of Guidelines for Research & Evaluation Ⅱ(AGREE Ⅱ), Reporting Items for Practice Guidelines in Healthcare (RIGHT), and Scientific, Transparent and Applicable Rankings (STAR) checklists. The project was registered on the international practice guidelines registry platform (PREPARE-2026CN1384). The working group systematically searched Chinese and English evidence addressing 12 clinical questions. Evidence was graded using the Oxford Centre for Evidence-Based Medicine (OCEBM) 2009 system, with structured appraisal of risk of bias, inconsistency, indirectness, and imprecision. Recommendations were formulated through two rounds of Delphi surveys and a face-to-face consensus meeting, with an agreement threshold of ≥75%. Results The consensus generated 12 recommendations covering indications, selection between jejunum and colon, preoperative assessment, surgical approach and reconstruction route, pedicled jejunal interposition (PJI), supercharged pedicled jejunal interposition (SPJ), indocyanine green (ICG) perfusion assessment, perioperative nutrition, management of anastomotic leakage, long-term follow-up, and special treatment scenarios. Given that the available direct evidence is predominantly derived from single-center retrospective cohorts and case series, recommendations extrapolated from general esophagectomy or other gastrointestinal surgical evidence are deliberately phrased with caution. Conclusion Jejunal interposition is a safe and effective approach for digestive tract reconstruction in patients with complex esophageal cancer in whom the stomach is unavailable. This consensus emphasizes that clinical decision-making should be individualized based on the patient's prior treatment history, reconstruction height, vascular anatomy, technical availability, and institutional experience in the Chinese context.

This paper focuses on extreme environments and systematically analyzes sleep disorders caused by multiple pathogenesis,including circadian rhythm disorder,yin-yang imbalance and qi-blood disorder under weightlessness,emotional depression due to environmental changes,abnormal diet and excretion,and six excesses pathogenic factors,in accordance with the theory of correspondence between nature and human.It proposes harmonizing yin and yang as the core therapeutic principle and guiding framework,with specific methods including calming rebellious qi-blood,regulating qi movement,harmonizing heart and kidney,and dredging and regulating blood vessels,thus forming the"one guiding principle and four specific methods"treatment strategy.Additionally,by integrating the modified application of classic formulas,a diagnostic and therapeutic approach targeting multi-dimensional pathogenesis is established.This study aims to promote the in-depth integration of Traditional Chinese Medicine(TCM)in extreme environmental medicine through TCM theories and innovative application of prescriptions,provide TCM-characterized solutions for health management of workers in extreme environments,and facilitate the transformation of extreme environmental medicine toward the modern medical model of"prevention-treatment integration".

Based on network pharmacology,molecular docking,and experimental validation,this study explored the mechanisms of Geranium wilfordii Maxim(GWM)in the treatment of liver injury.Mice were randomly divided into a control group(CON group),a model group(CCl4 group),a high-dose drug group(GWM-H group),and a low-dose group(GWM-L group).The liv-er injury model in mice was induced by CCl4,and liver tissue pathological morphology was ob-served,along with the measurement of the relative gene expression levels of liver inflammatory factors.Active ingredients of traditional Chinese medicine and target information of Chinese medi-cine and diseases were obtained through databases such as TCMSP,PubChem,Swiss Target Pre-diction,Super-PRED,Gene Cards,and DisGeNET.Intersecting the targets of liver injury,necropto-sis,and drugs yielded potential drug targets.String database was used for protein-protein interac-tion(PPI)analysis of the potential targets.Furthermore,Cytoscape was utilized to construct a net-work diagram of"drug-disease-active ingredient-intersection target,"Wei Sheng Xin was used for GO and KEGG pathway analysis.Molecular docking was performed using MOE software,and the results of molecular docking were experimentally validated to detect the expression of key targets in the RIPK1/RIPK3/MLKL signaling pathway.Animal experiments showed that compared to the CON group,the CCl4 group of mice exhibited a significant increase in liver organ index(P＜0.05),markedly elevated serum AST activity(P＜0.05),and a highly significant increase in ALT activity(P＜0.01).Pathological examination revealed chaotic liver lobules,severe hepatocyte steatosis,ex-tensive hepatocyte necrosis,and inflammatory cell infiltration in the livers of mice in the CCl4 group.In comparison to the CCl4 group,the GWM-H group showed a significant decrease in liver organ index(P＜0.05),while the GWM-L group displayed a downward trend.The GWM-H group exhibited a significant reduction in serum AST activity(P＜0.05),the GWM-L group showed a decreasing trend in serum AST activity,the GWM-H group demonstrated a highly significant de-crease in serum ALT activity(P＜0.01),and the GWM-L group displayed a significant decrease in serum ALT activity(P＜0.05).Histopathological examination revealed that the drug treatment groups could improve CCl4-induced liver injury,with the GWM-H group showing better efficacy than the GWM-L group.RT-qPCR results of liver tissues showed that compared to the CON group,the CCl4 group exhibited a highly significant increase in the relative expression of IL-1βand PGE2 mRNA(P＜0.01),while the mRNA relative expression of COX2 showed an increasing trend.In contrast,compared to the CCl4 group,the GWM-H group showed a remarkably significant decrease in the relative expression of IL-1βmRNA(P＜0.01),a significant decrease in PGE2 mR-NA expression(P＜0.05),and a decreasing trend in COX2 mRNA expression.Through network pharmacology,56 potential targets related to GWM in ameliorating necroptosis-induced liver injury were identified.Key targets,based on degree value,include TNF,Bcl2,HSP90AA1,and Caspase8,while the key components are quercetin,luteolin,kaempferol,and ellagic acid.Functional enrich-ment analysis yielded 2 173 entries for GO and 146 biological pathways for KEGG.Molecular doc-king results indicated a strong binding capacity between the main components of GWM and key targets.RT-qPCR experimental results showed that compared to the CON group,the CCl4 group exhibited a extremely significantly increase in the mRNA relative expression of TNF-α,TNFR1,MLKL(P＜0.01),significantly increase in the mRNA relative expression of FAS,RIPK1,RIPK3 mRNA(P＜0.05),and a significant decrease in Caspase 8 mRNA expression(P＜0.05).The addi-tion of GWM successfully reversed this trend;compared to the CCl4 group,the GWM-H group showed a highly significant decrease in the mRNA relative expression of TNF-α,TNFR1,FAS and MLKL mRNA(P＜0.01),significant decrease in RIPK1,RIPK3 mRNA expression(P＜0.05),and an increasing trend in CASPASE8 mRNA expression.GWM exerts hepatoprotective effects through multiple components and pathways,among which inhibition of the RIPK1/RIPK3/MLKL pathway reduces hepatocyte necroptosis,potentially serving as one of the essential mechanisms for its protective effects.

Based on network pharmacology,through molecular docking and experimental validation,the study explored the mechanism of the Hypericum japonicum-Rehmannia glutinosa-Salvia ple-beian compound(HRS)in the treatment of liver injury.Mice were randomly divided into a control group(CON group),a model group(CCL4 group),a high-dose drug group(HRS-H group),and a low-dose group(HRS-L group).A mouse liver injury model was established using CCL4 induction,liver tissue pathological morphology was observed,and the relative expression levels of liver in-flammatory cytokine genes was measured.Active ingredients of traditional Chinese medicine and targets related to Chinese medicine and diseases were obtained from databases such as Herb,TCM-SP,PubChem,Swiss Target Prediction,Gene Cards and DisGeNET.The intersection of targets was used to obtain potential drug targets.The potential targets were analyzed for protein-protein inter-action(PPI)using the string database and a network diagram of"drug-active component-intersec-tion target"was constructed using Cytoscape.DAVID database was used for GO and KEGG path-way analysis,and Auto Dock Tools software was used for molecular docking.Finally,the results of molecular docking by examining the expression of key target genes and downstream genes such as those related to the PI3K-AKT pathway and the autophagy pathway were experimentally valida-ted.Results:Animal experiment results showed that compared to the CON group,the CCL4 group of mice exhibited disrupted liver architecture,hepatocyte steatosis,vacuolization,and extensive in-flammatory cell infiltration.These characteristics were ameliorated by drug treatment groups with the HRS-H group demonstrating superior effects compared to the HRS-L group.RT-qPCR results from mouse livers showed significantly increased relative expression of TNF-α and INOS mRNA compared to the CON group in the CCL4 group(P＜0.01),and significantly increased IL-1β mR-NA relative expression(P＜0.05).Compared to the CCL4 group,the HRS-H group showed signifi-cantly decreased TNF-α,INOS,and IL-1β mRNA relative expressions(P＜0.01).155 potential tar-gets for HRS in alleviating liver damage were identified through network pharmacology,with top-ranked key target points including STAT3,SRC,PIK3R1,PIK3CA,AKT1,HSP90A11,EGFR,and ESR.Key active ingredients included Tetramethoxyluteolin,Hispidulin,Eupafolin,Kaempferol,and Eupaformonin.GO enrichment analysis yielded 940 entries,and KEGG enrichment analysis yielded 177 biological pathways.Molecular docking results showed a strong binding ability between the main components of HRS and key target points.RT-qPCR results showed increasing trends for EGFR,PI3KCA,HSP90A11,and NF-κB mRNA compared to the CON group in the CCL4 group,significantly increased AKT1 mRNA relative expression(P＜0.05),significant decreases in ULK1,ATG5,LC3B,and ATG7 mRNA relative expressions(P＜0.05),and extremely significant decreases in PTEN,ATG13,BECLIN-1,ATG16L1,ATG12,ATG4B,and ATG3 mRNA relative expressions(P＜0.01).Compared to the CCL4 group,the HRS-H group showed significantly de-creased PI3KCA,HSP90A11,and NF-κB mRNA relative expressions(P＜0.05),extremely signif-icantly decreased EGFR,AKT1,and mTOR mRNA relative expressions(P＜0.01),increased ULK1 relative expression trends,significantly increased PTEN,ATG16L1,ATG5,LC3B,and ATG7 mRNA relative expressions(P＜0.05),extremely significantly increased ATG13,BECLIN-1,ATG12,ATG4B,and ATG3 mRNA relative expressions(P＜0.01).Conclusion:The HRS ex-erts hepatoprotective effects through multi-component,multi-pathway approaches,with alleviating inflammation and promoting hepatocyte autophagy through PI3K-AKT pathway likely being im-portant mechanisms for its protective effects.

Prosthesis loosening is the leading cause of postoperative revision in unicompartmental knee arthroplasty (UKA). The deviation of medial and lateral translational installation of the prosthesis during surgery is a common clinical phenomenon and an important factor in increasing the risk of prosthesis loosening. This study established a UKA finite element model and a bone-prosthesis fixation interface micromotion prediction model. The predicted medial contact force and joint motion of the knee joint from a patient-specific lower extremity musculoskeletal multibody dynamics model of UKA were used as boundary conditions. The effects of 9 femoral component medial and lateral translational installation deviations on the Von Mises stress of the proximal tibia, the contact stress, and the micro-motion of the bone prosthesis fixation interface were quantitatively studied. It was found that compared with the neutral position (a/A of 0.492), the lateral translational deviation of the femoral component significantly increased the tibial Von Mises stress and the bone-prosthesis fixation interface contact stress. The maximum Von Mises stress and the maximum contact stress of the fixation interface increased by 14.08% and 143.15%, respectively, when a/A was 0.361. The medial translational deviation of the femoral component significantly increased the bone-prosthesis fixation interface micro-motion. The maximum value of micromotion under the conditions of femoral neutral and medial translation deviation was in the range of 20-50 μm, which is suitable for osseointegration. Therefore, based on considerations such as the micromotion range suitable for osseointegration reported in the literature, the risk of reducing prosthesis loosening, and factors that may induce pain, it is recommended that clinicians control the mounting position of the femoral component during surgery within the safe range of 0-4 mm medial translation deviation.
Humans ; Arthroplasty, Replacement, Knee/methods* ; Finite Element Analysis ; Biomechanical Phenomena ; Knee Prosthesis ; Tibia/surgery* ; Femur/surgery* ; Stress, Mechanical ; Prosthesis Failure ; Knee Joint/surgery* ; Prosthesis Design

Although metal blocks have been widely used for reconstructing uncontained tibial bone defects, the influence of their elastic modulus on the stability of tibial prosthesis fixation remains unclear. Based on this, a finite element model incorporating constrained condylar knee (CCK) prosthesis, tibia, and metal block was established. Considering the influence of the post-restraint structure of the prosthesis, the effects of variations in the elastic modulus of the block on the von Mises stress distribution in the tibia and the block, as well as on the micromotion at the bone-prosthesis fixation interface, were investigated. Results demonstrated that collision between the insert post and femoral prosthesis during tibial internal rotation increased tibial von Mises stress, significantly influencing the prediction of block elastic modulus variation. A decrease in the elastic modulus of the metal block resulted in increased von Mises stress in the proximal tibia, significantly reduced von Mises stress in the distal tibia, decreased von Mises stress of the block, and increased micromotion at the bone-prosthesis fixation interface. When the elastic modulus of the metal block fell below that of bone cement, inadequate block support substantially increased the risk of stress shielding in the distal tibia and fixation interface loosening. Therefore, this study recommends that biomechanical investigations of CCK prostheses must consider the post-constraint effect, and the elastic modulus of metal blocks for bone reconstruction should not be lower than 3 600 MPa.
Knee Prosthesis ; Humans ; Finite Element Analysis ; Tibia/surgery* ; Elastic Modulus ; Arthroplasty, Replacement, Knee/methods* ; Stress, Mechanical ; Metals ; Prosthesis Design ; Knee Joint/surgery* ; Biomechanical Phenomena