BACKGROUND:The long-term patency rate of synthetic blood vessels remains a significant challenge that requires urgent attention.Enhancing the anticoagulant performance of small-caliber artificial blood vessels is crucial in ensuring their long-term efficacy.OBJECTIVE:To investigate the anticoagulation activity of polycaprolactone/low molecular weight fucoidan nanofibers with shell core structure and determine the effect on the activity of human umbilical vein endothelial cells.METHODS:Polycaprolactone nanofiber membranes and polycaprolactone/low molecular weight fucoidan nanofiber membranes with polycaprolactone as shell layer and low molecular weight fucoidan as core layer were prepared by emulsion electrospinning method(the mass ratio of low molecular weight fucoidan to polycaprolactone was 10％,25％,40％,and 55％,respectively).The morphology and structure of the fibers were characterized by scanning electron microscopy,fluorescence microscopy,and infrared spectroscopy.The mechanical strength of the fiber membranes was detected by tensile test.The loading rate and sustained release rate of low molecular weight fucoidan in the nanofibers were detected by 1,9-dimethylmethylene blue dye.The anticoagulant properties of the fiber membranes were verified by hemolysis test,dynamic coagulation test,plasma recalcification test,and platelet adhesion test.The five fiber membranes were co-cultured with human umbilical vein endothelial cells.The cell proliferation was detected by CCK-8 assay and the cell morphology was observed by fluorescence microscopy.RESULTS AND CONCLUSION:(1)Scanning electron microscope showed that the surface of polycaprolactone/low molecular weight brown algae polysaccharide nanofiber membrane was smooth,the fiber diameter was uniform,and there was no obvious beaded structure.With the increase of low molecular weight brown algae polysaccharide content in the fiber membrane,the diameter of the fiber membrane increased and the maximum tensile stress decreased,but it still met the mechanical properties requirements of small-caliber artificial blood vessels.Fluorescence images and infrared spectra confirmed that low molecular weight brown algae polysaccharide was successfully loaded into polycaprolactone nanofiber membrane,and the low molecular weight brown algae polysaccharide loaded in each group of fiber membranes was released suddenly within 12 hours and released at a relatively low rate after 48 hours.(2)Compared with polycaprolactone nanofiber membrane,polycaprolactone/low molecular weight brown algae polysaccharide nanofiber membrane had better anticoagulant activity,among which the group with a mass ratio of low molecular weight brown algae polysaccharide to polycaprolactone of 25％had the best anticoagulant effect.All five fiber membranes supported the growth and proliferation of human umbilical vein endothelial cells without affecting cell morphology and had no obvious cytotoxicity.(3)The results show that the polycaprolactone/low molecular weight brown algae polysaccharide nanofiber membrane has good anticoagulant function,blood compatibility,and cell compatibility.

BACKGROUND:The long-term patency rate of synthetic blood vessels remains a significant challenge that requires urgent attention.Enhancing the anticoagulant performance of small-caliber artificial blood vessels is crucial in ensuring their long-term efficacy.OBJECTIVE:To investigate the anticoagulation activity of polycaprolactone/low molecular weight fucoidan nanofibers with shell core structure and determine the effect on the activity of human umbilical vein endothelial cells.METHODS:Polycaprolactone nanofiber membranes and polycaprolactone/low molecular weight fucoidan nanofiber membranes with polycaprolactone as shell layer and low molecular weight fucoidan as core layer were prepared by emulsion electrospinning method(the mass ratio of low molecular weight fucoidan to polycaprolactone was 10％,25％,40％,and 55％,respectively).The morphology and structure of the fibers were characterized by scanning electron microscopy,fluorescence microscopy,and infrared spectroscopy.The mechanical strength of the fiber membranes was detected by tensile test.The loading rate and sustained release rate of low molecular weight fucoidan in the nanofibers were detected by 1,9-dimethylmethylene blue dye.The anticoagulant properties of the fiber membranes were verified by hemolysis test,dynamic coagulation test,plasma recalcification test,and platelet adhesion test.The five fiber membranes were co-cultured with human umbilical vein endothelial cells.The cell proliferation was detected by CCK-8 assay and the cell morphology was observed by fluorescence microscopy.RESULTS AND CONCLUSION:(1)Scanning electron microscope showed that the surface of polycaprolactone/low molecular weight brown algae polysaccharide nanofiber membrane was smooth,the fiber diameter was uniform,and there was no obvious beaded structure.With the increase of low molecular weight brown algae polysaccharide content in the fiber membrane,the diameter of the fiber membrane increased and the maximum tensile stress decreased,but it still met the mechanical properties requirements of small-caliber artificial blood vessels.Fluorescence images and infrared spectra confirmed that low molecular weight brown algae polysaccharide was successfully loaded into polycaprolactone nanofiber membrane,and the low molecular weight brown algae polysaccharide loaded in each group of fiber membranes was released suddenly within 12 hours and released at a relatively low rate after 48 hours.(2)Compared with polycaprolactone nanofiber membrane,polycaprolactone/low molecular weight brown algae polysaccharide nanofiber membrane had better anticoagulant activity,among which the group with a mass ratio of low molecular weight brown algae polysaccharide to polycaprolactone of 25％had the best anticoagulant effect.All five fiber membranes supported the growth and proliferation of human umbilical vein endothelial cells without affecting cell morphology and had no obvious cytotoxicity.(3)The results show that the polycaprolactone/low molecular weight brown algae polysaccharide nanofiber membrane has good anticoagulant function,blood compatibility,and cell compatibility.

OBJECTIVE: To investigate the effectiveness of Holosight robotic navigation-assisted percutaneous cannulated screw fixation for femoral neck fractures. METHODS: A retrospective analysis was conducted on 65 patients with femoral neck fractures treated with cannulated screw fixation between January 2022 and February 2024. Among them, 31 patients underwent robotic navigation-assisted screw placement (navigation group), while 34 underwent conventional freehand percutaneous screw fixation (freehand group). Baseline characteristics, including age, gender, fracture side, injury mechanism, Garden classification, Pauwels classification, and time from injury to operation, showed no significant differences between the two groups ( P>0.05). The operation time, intraoperative blood loss, fluoroscopy frequency, fracture healing time, and complications were recorded and compared, and hip function was evaluated by Harris score at last follow-up. Postoperative anteroposterior and lateral hip X-ray films were taken to assess screw distribution accuracy, including deviation from the femoral neck axis, inter-screw parallelism, and distance from screws to the femoral neck cortex. RESULTS: No significant difference was observed in operation time between the two groups ( P>0.05). However, the navigation group demonstrated superior outcomes in intraoperative blood loss, fluoroscopy frequency, deviation from the femoral neck axis, inter-screw parallelism, and distance from screws to the femoral neck cortex ( P<0.05). No incision infections or deep vein thrombosis occurred. All patients were followed up 12-18 months (mean, 16 months). In the freehand group, 1 case suffered from cannulated screw dislodgement and nonunion secondary to osteonecrosis of femoral head at 1 year after operation, 1 case suffered from screw penetration secondary to osteonecrosis of femoral head at 5 months after operation; and 1 case suffered from nonunion secondary to osteonecrosis of femoral head at 6 months after operation in the navigation group. All the 3 patients underwent internal fixators removal and total hip arthroplasty. There was no significant difference in the incidence of complications between the two groups ( P>0.05). The fracture healing time and hip Harris score at last follow-up in the navigation group were significantly better than those in the freehand group ( P<0.05). CONCLUSION Compared to freehand percutaneous screw fixation, Holosight robotic navigation-assisted cannulated screw fixation for femoral neck fractures achieves higher precision, reduced intraoperative radiation exposure, smaller incisions, and superior postoperative hip function recovery.
Humans ; Femoral Neck Fractures/diagnostic imaging* ; Bone Screws ; Fracture Fixation, Internal/instrumentation* ; Male ; Female ; Retrospective Studies ; Robotic Surgical Procedures/methods* ; Middle Aged ; Aged ; Adult ; Treatment Outcome ; Operative Time ; Fracture Healing ; Surgery, Computer-Assisted/methods* ; Fluoroscopy

Objective:To explore the clinical efficacy of retrograde tibial intramedullary nail (RTN) combined with less invasive stabilization system (LISS) in the treatment of distal femoral fractures.Methods:A retrospective analysis was conducted on the data of 11 patients with distal femoral fractures who underwent RTN combined with LISS locking plate treatment at the 909th Hospital from June 2021 to December 2022. There were 5 males and 6 females, with an average age of 56.5±17.5 years. The fracture types were AO/OTA 33A2 in 2 cases, A3 in 2 cases, C1 in 2 cases, and C2 in 2 cases. There were 3 cases of periprosthetic femoral fractures after total knee arthroplasty (TKA), all classified as Rorabeck type Ⅱ. They were treated with retrograde intramedullary nailing of the tibia combined with a minimally invasive lateral internal fixation system. The operation time, intraoperative blood loss, fracture healing time, full weight-bearing time, femorotibial angle, range of motion (ROM) of the knee joint, Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) for pain, and complications were recorded.Results:The operation was successfully completed in all 11 cases. The operation time was 98.3±9.0 min (range 83-115 min), and the intraoperative blood loss was 167.8±24.3 ml (range 120-210 ml). All 11 cases were followed up for 11.0±1.9 months (range 9-15 months). The healing time of 11 cases was 5.3±0.8 months (range 4-6 months) after operation. The time of complete weight-bearing activity after operation was 55.7±6.5 d (range 46-67 d). At the last follow-up, the femoral-tibial angle of 11 cases was 171.2°±1.8° (range 169°-174°), the ROM of knee joint was 129.5°±4.7° (range 120°-135°), and the HSS score was 86.8±6.9 points (range 69-95 points). There were no major complications except for one case of superficial infection of surgical incision after operation.Conclusion:RTN combined with lateral LISS locking plate showed good clinical effect with the advantages of less trauma, reliable fixation, rapid recovery, less postoperative complications.

Objective To establish atopic dermatitis(AD)-like models in BALB/c mice using three chemical inducers,calcipotriol(MC903),2,4-dinitrochlorobenzene(DNCB),and oxazolone(OXA),and to explore the occurrence of ferroptosis in the different models.Methods Healthy 7-week-old female BALB/c mice were divided randomly into eight groups(n=8 mice per group)based on the induction site(ear/dorsal skin)and inducer:ear/dorsal control groups,MC903 ear/dorsal model groups,DNCB ear/dorsal model groups,and OXA ear/dorsal model groups.Models were established by topical application of the respective agents at specified concentrations.Mice in the MC903 ear/dorsal groups underwent continuous induction for 14 d.Mice in the DNCB and OXA ear/dorsal groups were sensitized for 3 consecutive days,4 days after the sensitization was completedand then challenged 12 times on day 8 and every other day for up to day 30.Skin lesions were observed and skin thickness was measured.Plasma levels of reactive oxygen species(ROS),interleukin(IL)-4,interferon(IFN)-γ,and malondialdehyde(MDA)were detected,the skin was examined by histopathological staining and ultrastructural observation,and expression levels of ferroptosis-related proteins(glutathione peroxidase 4(GPX4),ferritin heavy chain 1(FTH1),long-chain-fatty-acid-CoA ligase 4(ACSL4),transferrin receptor 1(TfR1))were detected by Western Blot.Results Compared with each control mice,all model mice exhibited obvious redness,swelling,scratching,desquamation,and rough thickening of the skin,and skin thickness was significantly increased(P＜0.01).ROS,IFN-γ,IL-4,and MDA levels were elevated to varying extents(P＜0.05)and histopathological features,including epidermal hyperplasia,keratinocyte degeneration,dermal vascular congestion,and immune cell infiltration,were detected in model mice.Transmission electron microscopy also revealed mitochondrial membrane rupture,increased density,and cristae reduction.Expression levels of ferroptosis markers were dysregulated,including significantly decreased GPX4/FTH1(P＜0.05)and increased ACSL4/TfR1 expression(P＜0.05).Conclusions All three chemicals successfully induced AD-like phenotypes in BALB/c mice through site-specific applications.Ferroptosis is involved in the pathological process of AD,but heterogeneity exists among inducers and modeling sites.

BACKGROUND:The age distribution of patients with distal femur fracture is bimodal,being more common in young adults with high-energy injuries and older individuals with low-energy injuries.In cases of complex distal femoral fractures,a single less invasive stabilization system or retrograde femoral nail is insufficient to provide a stable environment for fracture healing and combined fixation is often necessary.OBJECTIVE:A novel combined fixation method(less invasive stabilization system combined with retrograde tibial nail)was developed for the treatment of type A3 distal femur fractures.Using finite element analysis,the bio-mechanical properties of this method were compared with two common combined fixation methods—dual plate(less invasive stabilization system combined with locking compression plate)and nail plate combination(less invasive stabilization system combined with retrograde femoral nail).This study aims to provide a theoretical basis for the selection of clinical internal fixation methods for distal femur fracture.METHODS:CT images of a 23-year-old healthy male volunteer were utilized to reconstruct the femur three-dimensional model using Mimics and Geomagic Studio software.This model was then compared with in vitro finite element analysis data from existing literature to validate the accuracy of the femoral three-dimensional model.The three-dimensional model of type A3 distal femur fractures and internal fixation were then created using Creo 5.0 software.Three kinds of different combined fixation methods(less invasive stabilization system+retrograde tibial nail,less invasive stabilization system+locking compression plate,less invasive stabilization system+retrograde femoral nail)were assembled and subjected to Boolean operation to establish three sets of finite element models.These models were then imported into Abaqus finite element analysis software to assign material properties,apply consistent boundary conditions,and submit calculations under three loads(normal standing,slow walking,and descending stairs).The resulting stress distribution within the internal fixation as well as overall and local deformation of the femur was analyzed.Furthermore,the failure risk and anti-deformation ability of the new combined fixation method(less invasive stabilization system combined with retrograde tibial nail)were evaluated.RESULTS AND CONCLUSION:(1)Although the anti-deformation ability of the less invasive stabilization system combined with retrograde tibial nail was approximately 10％lower than that of the less invasive stabilization system combined with locking compression plate,it was comparable to that of less invasive stabilization system combined with retrograde femoral nail and demonstrated good anti-deformation ability.(2)The stiffness of the femur with all three combined fixation methods remained consistent during gait,while femur displacement increased linearly with load,indicating high stability.(3)The failure risk associated with less invasive stabilization system combined with retrograde tibial nail was lower than that of the other two methods,with a 2.94％reduction in failure risk compared to less invasive stabilization system combined with locking compression plate.(4)This new combined fixation method offers distinct advantages in terms of anti-deformation ability,safety,and effectiveness,laying a theoretical foundation for further clinical application.

Objective To establish atopic dermatitis(AD)-like models in BALB/c mice using three chemical inducers,calcipotriol(MC903),2,4-dinitrochlorobenzene(DNCB),and oxazolone(OXA),and to explore the occurrence of ferroptosis in the different models.Methods Healthy 7-week-old female BALB/c mice were divided randomly into eight groups(n=8 mice per group)based on the induction site(ear/dorsal skin)and inducer:ear/dorsal control groups,MC903 ear/dorsal model groups,DNCB ear/dorsal model groups,and OXA ear/dorsal model groups.Models were established by topical application of the respective agents at specified concentrations.Mice in the MC903 ear/dorsal groups underwent continuous induction for 14 d.Mice in the DNCB and OXA ear/dorsal groups were sensitized for 3 consecutive days,4 days after the sensitization was completedand then challenged 12 times on day 8 and every other day for up to day 30.Skin lesions were observed and skin thickness was measured.Plasma levels of reactive oxygen species(ROS),interleukin(IL)-4,interferon(IFN)-γ,and malondialdehyde(MDA)were detected,the skin was examined by histopathological staining and ultrastructural observation,and expression levels of ferroptosis-related proteins(glutathione peroxidase 4(GPX4),ferritin heavy chain 1(FTH1),long-chain-fatty-acid-CoA ligase 4(ACSL4),transferrin receptor 1(TfR1))were detected by Western Blot.Results Compared with each control mice,all model mice exhibited obvious redness,swelling,scratching,desquamation,and rough thickening of the skin,and skin thickness was significantly increased(P＜0.01).ROS,IFN-γ,IL-4,and MDA levels were elevated to varying extents(P＜0.05)and histopathological features,including epidermal hyperplasia,keratinocyte degeneration,dermal vascular congestion,and immune cell infiltration,were detected in model mice.Transmission electron microscopy also revealed mitochondrial membrane rupture,increased density,and cristae reduction.Expression levels of ferroptosis markers were dysregulated,including significantly decreased GPX4/FTH1(P＜0.05)and increased ACSL4/TfR1 expression(P＜0.05).Conclusions All three chemicals successfully induced AD-like phenotypes in BALB/c mice through site-specific applications.Ferroptosis is involved in the pathological process of AD,but heterogeneity exists among inducers and modeling sites.

Objective:To explore the clinical efficacy of retrograde tibial intramedullary nail (RTN) combined with less invasive stabilization system (LISS) in the treatment of distal femoral fractures.Methods:A retrospective analysis was conducted on the data of 11 patients with distal femoral fractures who underwent RTN combined with LISS locking plate treatment at the 909th Hospital from June 2021 to December 2022. There were 5 males and 6 females, with an average age of 56.5±17.5 years. The fracture types were AO/OTA 33A2 in 2 cases, A3 in 2 cases, C1 in 2 cases, and C2 in 2 cases. There were 3 cases of periprosthetic femoral fractures after total knee arthroplasty (TKA), all classified as Rorabeck type Ⅱ. They were treated with retrograde intramedullary nailing of the tibia combined with a minimally invasive lateral internal fixation system. The operation time, intraoperative blood loss, fracture healing time, full weight-bearing time, femorotibial angle, range of motion (ROM) of the knee joint, Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) for pain, and complications were recorded.Results:The operation was successfully completed in all 11 cases. The operation time was 98.3±9.0 min (range 83-115 min), and the intraoperative blood loss was 167.8±24.3 ml (range 120-210 ml). All 11 cases were followed up for 11.0±1.9 months (range 9-15 months). The healing time of 11 cases was 5.3±0.8 months (range 4-6 months) after operation. The time of complete weight-bearing activity after operation was 55.7±6.5 d (range 46-67 d). At the last follow-up, the femoral-tibial angle of 11 cases was 171.2°±1.8° (range 169°-174°), the ROM of knee joint was 129.5°±4.7° (range 120°-135°), and the HSS score was 86.8±6.9 points (range 69-95 points). There were no major complications except for one case of superficial infection of surgical incision after operation.Conclusion:RTN combined with lateral LISS locking plate showed good clinical effect with the advantages of less trauma, reliable fixation, rapid recovery, less postoperative complications.

BACKGROUND:The age distribution of patients with distal femur fracture is bimodal,being more common in young adults with high-energy injuries and older individuals with low-energy injuries.In cases of complex distal femoral fractures,a single less invasive stabilization system or retrograde femoral nail is insufficient to provide a stable environment for fracture healing and combined fixation is often necessary.OBJECTIVE:A novel combined fixation method(less invasive stabilization system combined with retrograde tibial nail)was developed for the treatment of type A3 distal femur fractures.Using finite element analysis,the bio-mechanical properties of this method were compared with two common combined fixation methods—dual plate(less invasive stabilization system combined with locking compression plate)and nail plate combination(less invasive stabilization system combined with retrograde femoral nail).This study aims to provide a theoretical basis for the selection of clinical internal fixation methods for distal femur fracture.METHODS:CT images of a 23-year-old healthy male volunteer were utilized to reconstruct the femur three-dimensional model using Mimics and Geomagic Studio software.This model was then compared with in vitro finite element analysis data from existing literature to validate the accuracy of the femoral three-dimensional model.The three-dimensional model of type A3 distal femur fractures and internal fixation were then created using Creo 5.0 software.Three kinds of different combined fixation methods(less invasive stabilization system+retrograde tibial nail,less invasive stabilization system+locking compression plate,less invasive stabilization system+retrograde femoral nail)were assembled and subjected to Boolean operation to establish three sets of finite element models.These models were then imported into Abaqus finite element analysis software to assign material properties,apply consistent boundary conditions,and submit calculations under three loads(normal standing,slow walking,and descending stairs).The resulting stress distribution within the internal fixation as well as overall and local deformation of the femur was analyzed.Furthermore,the failure risk and anti-deformation ability of the new combined fixation method(less invasive stabilization system combined with retrograde tibial nail)were evaluated.RESULTS AND CONCLUSION:(1)Although the anti-deformation ability of the less invasive stabilization system combined with retrograde tibial nail was approximately 10％lower than that of the less invasive stabilization system combined with locking compression plate,it was comparable to that of less invasive stabilization system combined with retrograde femoral nail and demonstrated good anti-deformation ability.(2)The stiffness of the femur with all three combined fixation methods remained consistent during gait,while femur displacement increased linearly with load,indicating high stability.(3)The failure risk associated with less invasive stabilization system combined with retrograde tibial nail was lower than that of the other two methods,with a 2.94％reduction in failure risk compared to less invasive stabilization system combined with locking compression plate.(4)This new combined fixation method offers distinct advantages in terms of anti-deformation ability,safety,and effectiveness,laying a theoretical foundation for further clinical application.

Objective:To evaluate the fixation with a locking fibular intramedullary nail for treatment of extra-articular distal tibial fracture complicated with fibular fracture (AO/OTA 43A).Methods:A retrospective study was conducted to analyze the data of 31 patients who had been treated by fixation with a locking fibular intramedullary nail for extra-articular distal tibial fracture complicated with fibular fracture at Department of Orthopaedics, The 909th Hospital of Joint Logistics Support Force between January 2018 and December 2021. There were 20 males and 11 females; (41.5±15.7) years in age; AO classification of the distal tibial fractures: 10 cases of type 43A1, 10 cases of type 43A2, and 11 cases of type 43A3; 11 open fractures and 20 closed fractures. Fracture healing, fibular alignment, tibiotalar angle, and incidence of complications were regularly followed up and recorded after surgery. At the last follow-up, the ankle joint function was assessed using the Olerud Molander ankle score (OMAS) and the ankle-hindfoot score of American Orthopaedic Foot and Ankle Society (AOFAS).Results:All the 31 patients were followed up for (17.5±3.3) months after surgery. All of them achieved fine fracture union. The union time was (3.9±0.8) months for tibial fractures, and (3.6±0.9) months for fibular fractures. No internal fixation failure was observed. The last follow-up revealed the following: the fibular alignment was 1.8°±1.3° and the ankle tibiotalar angle 9.1°±2.3°; no fibular rotation, shortening, or separation displacement happened; the OMAS score was (88.3±6.2) points, and the AOFAS ankle-hindfoot score (87.4±6.0) points. Two patients required removal of the distal locking screw of the fibular intramedullary nail due to soreness around the lateral malleolus caused by screw loosening. There were no other related complications.Conclusion:Fixation with a locking fibular intramedullary nail is an effective treatment for extra-articular distal tibial fracture complicated with fibular fracture, demonstrating advantages of firm fixation, limited complications, minimal trauma and soft tissue irritation, and good clinical efficacy.