Femoral intertrochanteric fracture is one of the common types of fractures in the elderly. With the general improvement of medical and living standards, the number of elderly people is increasing, and the problem of osteoporosis has also become relatively prominent. Therefore, low violence can usually cause fractures in this area of the elderly, which has a significant negative impact on the quality of life of elderly patients. With the further development of medical technology and internal fixation materials, the emergence of proximal femoral nail antirotation(PFNA) has greatly improved the treatment effect of femoral intertrochanteric fractures in elderly patients. However, with the increasing number of patients treated, internal fixation failures have gradually been reported. In recent years, proximal femoral biomimetic intramedullary nail(PFBN) has been reported to have good clinical efficacy. Therefore, this article mainly elaborates on the theoretical basis, design characteristics, biomechanics, and clinical efficacy research of PFBN, providing more reference for the clinical treatment of femoral intertrochanteric fractures in elderly patients in the future.

Objective:To investigate the effect of the ratio of the maximum diameter of aneurysm sac to age (R) on the long-term efficacy of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) in patients with infrarenal abdominal aortic aneurysm (IAAA).Methods:This is a retrospective cohort study.The clinical data of 317 patients with IAAA who underwent surgical repair in the Department of Vascular Surgery,the Third Affiliated Hospital of Sun Yat-Sen University from January 2016 to October 2022 were retrospectively collected.There were 266 males and 51 females,aged (69.7±8.3) years (range:37 to 87 years).The R value of the patient was calculated and the receiver operating characteristic(ROC) curve was used to establish a model to calculate the optimal cut-off value.The propensity score matching method was used to match the baseline data of patients in the EVAR and OSR group by 3∶1 (the caliper value was 0.05),and the patients were stratified according to the cutoff value of R, and the postoperative efficacy and survival of the patients were analyzed.The primary endpoint was the total mortality rate,and the secondary endpoints included the occurrence of postoperative complications and reintervention.Pearson χ2 or Fisher ′s exact test was used for categorical variables, and independent sample t test or Wilcoxon rank sum test was used for continuous variables to compare differences between groups.The survival curves of the two groups were described by Kaplan-Meier method. Results:After propensity score matching,198 cases were in the EVAR group and 66 cases were in the OSR group.The ROC model showed that the best cut-off value of R value was 0.90,and the two groups were divided into two layers:R<0.90 and R≥0.90.Among them,112 patients with R<0.90 (84 cases of EVAR,28 cases of OSR);there were 152 patients with R≥0.90 (114 cases of EVAR and 38 cases of OSR).The follow-up time was (23.6±1.6) months (range:1 to 70 months).In the R≥0.90 stratification,the total mortality (26.3% vs.5.3%, χ2=7.600， P=0.006),complication rate (44.7% vs.26.3%, χ2=4.025， P=0.045), and secondary intervention rate (31.6% vs.13.2%, χ2=4.910， P=0.027) in the EVAR group were higher than those in the OSR group.In the R<0.90 stratification,there was no significant difference in the total mortality rate (13.1% vs.10.7%, χ2=0.109， P=0.741), complication rate (28.6% vs.35.7%, χ2=0.507， P=0.477) and secondary intervention rate (14.3% vs.21.4%, χ2=0.353， P=0.552) between the two groups. Conclusions:When R≥0.90 in IAAA patients,OSR maybe more beneficial to patients in terms of survival rate,postoperative complication rate and secondary intervention rate than EVAR.When R<0.90,there are no significant differences in survival rate,complication rate and secondary intervention rate between the two surgical methods.

Objective: To synthesis a Gd-labeled molecular probe capable of responding to fibroblast activation protein(FAP) highly expressed in tumor-associated fibroblasts for magnetic resonance imaging studies of pancreatic cancer. Methods: The chemical structure of Z-Gly-Pro-Cys-Lys(Gd-DOTA)-CBT(contrast agent 1) was characterized through mass spectrometry analysis.High-performance liquid chromatography(HPLC) was used to verify the contrast agent 1 formed a dimer under the cleavage of fibroblast activation protease(FAP) in vitro,and further self-assembled to form Gd-nanoparticles.The cell counting Kit-8(CCK-8) assay was used for biological safety analysis.BxPc-3 tumor-bearing mice were established and randomly divided into three groups,3 mice intravenously(i.v.) injected with 0.08 mmol/kg contrast agent 1 through tail vein were designated as the experimental group,3mice i.v.injected with 0.08 mmol/kg Gd-DTPA were designated as the control group,and 3 mice i.v.injected with normal saline were designated as the blank control group(n=3).Dynamic MR scanning from 0 to 3 hours was performed for them,respectively.The enhancement effects of T1-and T2-weighted imaging were observed and the rate of change in the tumor-to-muscle ratio(T/M) over time was analyzed. Results: Contrast agent 1 efficiently responded to FAP in vitro,forming dimers under the action of FAP,and further self-assembled to form nanoparticle structures.Contrast agent 1 has good biocompatibility.The BxPc-3 tumor-bearing mice showed that the T1-weighted contrast of the tumor reached its highest level at 2 h post injection of contrast agent 1 or Gd-DTPA.In T1-weighted imaging,the T/M at 2 h in the experimental group was 135.20%±0.06% of 0 h,the T/M at 2 h in the Gd-DTPA group was 115.70%±0.05% of 0 h and the T/M at 2 h in the saline group was 113.5%±0.02% of 0h.Compared with Gd-DTPA control group,the experimental group had significantly enhanced T1-weighted MR contrast,and the difference was statistically significant(P<0.01).In tumor T2-weighted imaging,the T/M quantitative analysis showed that the tumor T2-weighted contrast enhancement of the three groups was relatively small,and the T/M of the experimental group and the control group at 0.5 h was 94.60±0.03% and 106.30±0.04% of the 0 h,respectively.In the normal saline group,T/M at 0.5 h was 102.20±0.002% of that at 0 h,and no significant enhancement of the T2-weighted MR contrast of tumor was observed. Conclusion Successfully construct a FAP-responsive molecular probe which can self-assemble to form a Gd-nanoparticle structure in tumor cells under the cleavage of FAP,effectively improving the enrichment of Gd in the target region,and enhancing T1-weighted magnetic resonance imaging of pancreatic cancer,which has potential clinical application value.

Objective:To investigate the effect of the ratio of the maximum diameter of aneurysm sac to age (R) on the long-term efficacy of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) in patients with infrarenal abdominal aortic aneurysm (IAAA).Methods:This is a retrospective cohort study.The clinical data of 317 patients with IAAA who underwent surgical repair in the Department of Vascular Surgery,the Third Affiliated Hospital of Sun Yat-Sen University from January 2016 to October 2022 were retrospectively collected.There were 266 males and 51 females,aged (69.7±8.3) years (range:37 to 87 years).The R value of the patient was calculated and the receiver operating characteristic(ROC) curve was used to establish a model to calculate the optimal cut-off value.The propensity score matching method was used to match the baseline data of patients in the EVAR and OSR group by 3∶1 (the caliper value was 0.05),and the patients were stratified according to the cutoff value of R, and the postoperative efficacy and survival of the patients were analyzed.The primary endpoint was the total mortality rate,and the secondary endpoints included the occurrence of postoperative complications and reintervention.Pearson χ2 or Fisher ′s exact test was used for categorical variables, and independent sample t test or Wilcoxon rank sum test was used for continuous variables to compare differences between groups.The survival curves of the two groups were described by Kaplan-Meier method. Results:After propensity score matching,198 cases were in the EVAR group and 66 cases were in the OSR group.The ROC model showed that the best cut-off value of R value was 0.90,and the two groups were divided into two layers:R<0.90 and R≥0.90.Among them,112 patients with R<0.90 (84 cases of EVAR,28 cases of OSR);there were 152 patients with R≥0.90 (114 cases of EVAR and 38 cases of OSR).The follow-up time was (23.6±1.6) months (range:1 to 70 months).In the R≥0.90 stratification,the total mortality (26.3% vs.5.3%, χ2=7.600， P=0.006),complication rate (44.7% vs.26.3%, χ2=4.025， P=0.045), and secondary intervention rate (31.6% vs.13.2%, χ2=4.910， P=0.027) in the EVAR group were higher than those in the OSR group.In the R<0.90 stratification,there was no significant difference in the total mortality rate (13.1% vs.10.7%, χ2=0.109， P=0.741), complication rate (28.6% vs.35.7%, χ2=0.507， P=0.477) and secondary intervention rate (14.3% vs.21.4%, χ2=0.353， P=0.552) between the two groups. Conclusions:When R≥0.90 in IAAA patients,OSR maybe more beneficial to patients in terms of survival rate,postoperative complication rate and secondary intervention rate than EVAR.When R<0.90,there are no significant differences in survival rate,complication rate and secondary intervention rate between the two surgical methods.

Objective To study the stability of plate-assisted intramedullary nailing for fixing proximal third tibiafractures, compare and observe biomechanical characteristics of anterolateral or posteromedial plate-assisted intramedullary nailing after fixation of proximal third tibia fractures. Methods Eight artificial tibia of 4th-generation sawbones were divided into two groups based on location of the assisted plate, namely, anterolateral plate group and posteromedial plate group, with 4 specimens in each group. Each two locking bolts were fixed to theintramedullary nail proximally and distally, and each three bicortical screws were fixed to the plate proximally and distally. The specimens were osteotomized with a 10-mm defect which located 0. 5 cm to the proximal locking bolt of intramedullary nail or 5-6 cm distally to the knee joint line, in order to simulate an AO/ OTA 41-A2 type proximal third tibia fracture after fixation of intramedullary nail. After osteotomy was finished, axial compression test, three point bending test, cyclic loading and overstress test were conducted by mechanical testing machine. The results of axial stiffness and three-point stiffness between two groups were compared and analyzed. Results Axial compression test showed that the average axial stiffness in posteromedial plate group was lower than that in anterolateral plate group, but no significantly statistical differences were found between the two groups. Three point bending test showed that the average bending stiffness in posteromedial plate group was significantly higher than that in anterolateral plate group when stimulating either varus stress (plate located at pressure side of the fracture, t = 3. 679, P<0. 05) or valgus stress (plate located at tension side of the fracture, t = 8. 975, P<0. 05). Conclusions Plate-assisted intramedullary nailing for fixation of proximal third tibia fractures can minimize the angulation malalignment, improve the stability of nailed proximal tibial fragment and allow the early weight bearing. Both anterolateral and posteromedial plate-assisted intramedullary nail can provide satisfactory axial stability for proximal third tibia fractures, while posteromedial plate-assisted intramedullary nail shows better bending stability than anterolateral plate in countering varus or valgus stress deformity. This study provides an essential basis for clinical decision making about plate-assisted intramedullary nailing for fixing proximal third tibia fractures.

Objective:To analyze the therapeutic effect of sural neurocutaneous flap combined with antibiotic-impregnated calcium sulfate and autogenous iliac bone graft of chronic calcaneal osteomyelitis.Methods:A retrospective analysis was peformed in 29 patients with chronic calcaneal osteomyelitis treated with sural neurocutaneous flap combined with antibiotic-impregnated calcium sulfate and autogenous iliac bone graft in the Xi′an Honghui Hospital Affiliated to Xi′an Jiaotong University from April 2013 to January 2020. There were 19 males and 10 females, with the age of (45.38±12.85) years, ranged from 22 to 67 years. The course of disease was (16.00±6.96) months, ranged from 6 to 36 months. The skin defect area was (41.9±15.9) cm 2, ranged from 11.8 to 86.8 cm 2. The causes of injury: 18 cases of high fall, 6 cases of traffic accidents, 3 cases of heavy rolling, the remaining 2 cases were machine strangulation and sharp stab wounds. The inflammatory markers [white blood cell (WBC), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), C reactive protein (CRP)] and bone healing time were recorded before operation, 2, 4, 8 weeks and 6 months after operation. During the follow-up period, the flap texture, survival were observed, and the ankle-posterior foot function recovery was evaluated by the American Association of Foot and Ankle Surgery (AOFAS) score were observed before and after the operation, and the incidence of complications were recorded. The measurement data were expressed as mean±standard deviation ( ± s), and the t-test was used for inter-group comparison; the levels of WBC, ESR, PCT and CRP at different time points before and after operation were compared by repeated measurement ANOVA, and the LSD t-test was used for pairwise comparison. Results:All the 29 patients were followed up for (14.51±6.10) months, ranged from 6 to 30 months. All the flaps survived without abrasion, ulceration, or skin protrusion, and all patients could walk normally with shoes. There were 28 cases of stage I bone healing, with an average of (5.87±2.07) months, ranged from 3 to 12 months. The inflammatory indexes was significantly decreased at different time points after operation ( P<0.05). There was no significant difference between 6 months and 8 weeks after operation ( P>0.05), while there was significant difference at other time points ( P<0.05). The ankle-posterior foot score of AOFAS at 6 months after treatment was significantly higher than that before treatment (83.44±7.93 vs 55.37±8.07), the differences was statistically significant ( P<0.05). The clinical efficacy of foot function recovery was excellent in 12 cases, good in 15 cases and fair in 2 cases among 29 patients .The excellent and good rate was 93.1% (27/29). One patient recurred 1 month after operation and was re-implanted with antibiotic-loaded calcium sulfate mixed autogenous iliac bone after debridement, no recurrence was found. The total complication rate was 31.0%, but there was no significant impact on the patient's life in the later period. All patients returned to daily life and work. Conclusion:The treatment of chronic calcaneal osteomyelitis with sural neurocutaneous flap combined with antibiotic-impregnated calcium sulfate and autogenous iliac bone graft can effectively control infection, reconstruct calcaneal and soft tissue structure, promote functional recovery of affected limb, and ultimately improve the patient′s quality of life.

SARS-CoV-2 Omicron variant (B.1.1.529) was first discovered in South Africa in November 2021 and has since become a mainstream strain worldwide. Omicron variant was defined as the fifth "variant of concern (VOC)" by World Health Organization on November 26, 2021. This paper illustrates the mutation trends of Omicron variants in terms of SARS-CoV-2 genome and protein structure as well as nucleic acid site mutations and amino acid site mutations, describes the features of Omicron mutation sites in terms of lineage comparison among the VOCs and Omicron sublineages, and further highlights the influences of Omicron site mutations from the aspects of immune escape, virulence and transmission ability. Moreover, this paper also reviews the development of direct antiviral agents, antibodies and vaccines, aiming to provide reference for further investigation.

Objective:To analyze the therapeutic effect of 3D printing technology combined with locking plate fixation on femoral shaft fracture in patients with femoral deformity.Methods:The clinical data of 33 patients with femoral shaft fracture with femoral deformity who met the inclusion criteria and underwent locking plate fixation in the Xi′an Honghui Hospital Affiliated to Xi′an Jiaotong University from June 2014 to December 2020 were retrospectively analyzed. The patients were divided into 3D printing group ( n=18) and control group ( n=15) according to whether 3D printing was performed before operation. The 3D printing group including 11 males and 7 females with an age of (46.78±13.76) years.The control group including 9 males and 6 females with an age of (48.20±14.27) years.The operation time, intraoperative blood loss, fracture healing time and complications of the two groups were recorded. Visual analogue scale (VAS) scores of pain were evaluated before and 6, 12, 24, 48 and 72 h after operation. According to the Harris hip score, the Hospital for Special Surgery (HSS) knee score and The MOS 36-item short-from Health Survey (SF-36), the hip and knee function and quality of life of the patients before and 12 months after injury were evaluated. The measurement data were represented as mean±standard deviation( ± s), and the comparison between groups was conducted using the t-test; the comparison of count data between groups was conducted by Chi-square test or Fisher exact probability. Results:The operation time, intraoperative blood loss, and incidence of complications in the 3D printing group were (91.50±9.07) min, (191.11±16.01) mL, and 0(0/18), respectively, and those in the control group were (118.07±14.19) min, (270.27±17.59) mL, and 26.7% (4/15), the differences between the two groups were statistically significant ( P <0.05). The pain VAS scores of the 3D printing group were significantly better than those of the control group at 6, 12, 24, 48, and 72 h after operation ( P<0.05). There were no differences in fracture healing time and preoperative pain VAS between the two groups( P>0.05). There were no significant differences in hip function, knee function and quality of life scores between the two groups before injury and 12 months after injury( P>0.05). Conclusion:In the treatment of femoral shaft fractures in patients with femoral deformity with locking plate fixation, the application of 3D printing technology can be used for preoperative design and plate preshaping, which can shorten the operation time, reduce the amount of intraoperative blood loss, reduce the VAS of pain and the incidence of complications, improve the satisfaction of surgery, and provide a new option for the treatment of femoral shaft fractures in patients with femoral deformity.

Objective:To explore the clinical and imaging characteristics of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) caused by mitochondrial DNA 14453G>A (m.14453G>A) mutation.Methods:A case of MELAS caused by m.14453G>A mutation in the First Affiliated Hospital of Harbin Medical University on October 12, 2021 was reported. At the same time, the reported cases of MELAS and Leigh syndrome (LS) caused by the m.14453G>A mutation were reviewed. This enabled a comprehensive summarization, analysis, and comparison of these cases.Results:The patient was a female. She has suffered from the disease since 13-year old with seizures, accompanied by the disturbance of mood and the loss of memory. Brain magnetic resonance imaging findings consisted of lesions in frontal, parietal, occipital, temporal lobe and cerebellar. The patient was initially considered with autoimmune encephalitis and posterior reversible encephalopathy syndrome. Since direct sequencing of the complete mitochondrial genome from blood of the patient revealed m.14453G>A mutation in ND6 gene, and the mutation rate was 17.0%, the patient eventually diagnosed with MELAS based on clinical manifestations, imaging examinations, and genetic testing results. Using "m.14453G>A" as the search term, the relevant literature in China and abroad was retrieved and those with complete clinical data were identified. A total of 11 cases of m.14453G>A mutation including this case were reported, of whom 5 patients were diagnosed as MELAS, and 6 patients were diagnosed as LS. Among the 11 patients, those being adolescent or adult and with lesions in the cortex and subcortical white matter were probably be MELAS; those being infant or young child and with lesions in basal ganglia, thalamus and brainstem could be LS. Conclusions:Mitochondrial disease caused by m.14453G>A gene mutation shows a great heterogeneity, which can cause MELAS and LS. The clinical phenotype of the m.14453G>A mutation may be related to the age of onset and lesion′ s location.

Objective:To compare the clinical efficacy of femoral neck system (FNS) and cannulated screw fixation in the treatment of femoral neck fracture in the young and middle-aged patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 76 young and middle-aged patients with femoral neck fracture admitted to Honghui Hospital Affiliated to Xi′an Jiaotong University from March 2018 to September 2020, including 45 males and 31 females, aged 23-63 years [(49.5±8.2)years]. Garden classification of the fracture was 25 patients with type II, 34 with type III and 17 with type IV. Pauwels classification of the fracture was 16 patients with type I, 31 with type II and 29 with type III. A total of 40 patients were treated with cannulated screw fixation (cannulated screw group) and 36 patients with FNS fixation (FNS group). Operation time, frequency of fluoroscopy, length of hospital stay, weight-bearing time and bone union time were compared between the two groups. Hip function was assessed by Harris hip score at 6, 12 months after operation. The incidence of postoperative complications was observed.Results:All patients were followed up for 12-20 months [(15.2±1.7)months]. The frequency of fluoroscopy [(13.4±1.9)times], weight-bearing time [(11.1±1.9)weeks] and bone union time [(13.8±1.6)weeks] in FNS group were lower or shorter than those in cannulated screw group [(18.2±2.6)times, (15.7±1.6)weeks, (14.6±1.6)weeks] (all P<0.05 or 0.01). There were no significant differences in operation time, length of hospital stay and Harris hip score at 6, 12 months after operation between the two groups (all P>0.05). No postoperative infection occurred in both groups. In cannulated screw group, there were 4 patients with femoral neck shortening, 3 with deep venous thrombosis, 2 with internal fixation loosening, 2 with nail withdrawal and 1 with fracture non-union, showing the incidence of complications of 30% (12/40). In FNS group, there was 2 patients with femoral neck shortening, 1 with deep vein thrombosis and 1 with internal fixation loosening, showing the incidence of complications of 11% (4/36) ( P<0.05). Conclusion:For femoral neck fracture in the young and middle-aged patients, both FNS and cannulated screw fixation can obtain satisfactory efficacy, but FNS has the advantages of decreased frequency of intraoperative fluoroscopy, early weight bearing, reduced time to bone union and low incidence of complications.