简介：Ceramicsaregoodalternativetometalasbearingcouplematerialsbecauseoftheirbetterwearresistance.AFiniteElement(FE)studywasperformedtoinvestigatethecontactmechanicsandstressdistributionofCeramic-on-Ceramic(COC)hipresurfacingprostheses.Itwasfocusedinparticularonaparametricstudytoexaminetheeffectsofradialclearance,loading,aluminacoatingontheimplants,bonequality,andfixationofcup-boneinterface.Itwasfoundthatareductionintheradialclearancehadthemostsignificanteffectonthepredictedcontactpressuredistributionamongalloftheparametersconsideredinthisstudy.Itwasdeterminedthattherewasasignificantinfluenceofnon-metallicmaterials,suchastheboneunderneaththebearingcomponents,onthepredictedcontactmechanics.Stressshieldingwithinthebonetissuewasfoundtobeamajorconcernwhenregardingtheuseofceramicasanalternativetometallicresurfacingprostheses.Therefore,usingaluminaimplantswithametalbackingwasfoundtobethebestdesignforceramicresurfacingprosthesesinthisstudy.Theloading,bonequality,andacetabularcupfixationconditionswerefoundtohaveonlyminoreffectsonthepredictedcontactpressuredistributionalongthebearingsurfaces.

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简介：针对DV-Hop算法存在定位精度的问题,提出了一种基于差异演化粒子群的无线传感网络DV-Hop节点定位算法。首先通过引入差异演化计算的变异、交叉及选择过程,对传统粒子群优化算法进行了改进,维持了种群的多样性,从而提高了算法的全局搜索能力。然后,采用改进的粒子群优化算法对DV-Hop进行了优化计算并给出了具体流程。仿真实验结果显示,与传统DV-Hop算法和某些现有的改进算法,相比提出的改进DV-Hop定位算法具有较小的定位误差,有效提升了网络中节点定位的精度。

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简介：AbstractPurpose:Venous thromboembolism (VTE) is a major health issue among hip fracture patients. This study aimed to develop an information platform based on a mobile application and then evaluate whether information platform-based nursing could improve patient's drug compliance and reduce the incidence of VTE in hip fracture patients.Methods:This study retrospectively analyzed hip fracture patients who were treated with conventional prevention and intervention methods for VTE (control group) between January 2008 and November 2012, and prospectively analyzed hip fracture patients who were treated with nursing intervention based on the information platform (study group) between January 2016 and September 2017. All the patients included in the both groups were hip fracture patients who had an age over 50 years, treated with surgery, and hospitalized ≥ 48 h. Patients were excluded if they admitted to hospital due to old fractures, had a severe bleeding after 72 h of admission, diagnosed with any type of VTE, or refused to participate in the study. The information platform was divided into medical, nursing, and patient interface. Based on the information platform, medical practitioners and nurses could perform risk assessments, monitoring management and early warnings, preventions and treatments, health educations, follow-up, and other aspects of nursing interventions for patients. This study compared essential characteristics, drug compliance, VTE occurrence, and mean length of hospitalization between the two groups. Besides, a subgroup analysis was performed in the study group according to different drug compliances. SPSS 18.0 software (IBM Corp., NY, and USA) was used for statistical analysis.Results:Altogether 1177 patients were included in the control group, and 491 patients in the study group. Regarding baseline data, patients in the study group had more morbidities than those in the control group (p < 0.05). The difference of drug compliance between the two groups was statistically significant (p < 0.001): 761 (64.7%) of the patients in the control group and only 30 (6.1%) patients in the study group had poor drug compliance. In terms of VTE, 10.7% patients (126/1177) in the control group had VTE, and the rate in the study group was 7.1% (35/491), showing a statistically significant difference (p = 0.02). Moreover, the average length of hospitalization in the study group was also significantly lower than that in the control group (10.4 days vs. 13.7 days, p < 0.001). Subgroup analyses of the study group showed that the incidence of VTE in patients with poor, partial, and good compliances were 56.7% (17/30), 5.8% (10/171), and 2.8% (8/290), respectively, revealing a significantly huge difference (p < 0.001).Conclusions:Poor drug compliance leads to higher VTE occurrence. The information platform-based nursing can effectively improve the compliance of hip fracture patients and thus considerably reduce the incidence of VTE. The mobile application may be an effective tool to prevent VTE in hip fracture patients.

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简介：UHMWPEcompositesreinforcedwithBovineBoneHydroxyapatite(BHA)indifferentcontentswerepreparedbyheatpressingformationmethod.AhipjointwearsimulatorwasusedtoinvestigatethebiotribologicalbehaviorofUHMWPE/BHAcompositeacetabularcupsagainstCoCrMoalloyfemoralheadsinbovinesynovialubricationat37±1℃.ItwasfoundthattheadditionofBHApowdertoUHMWPEcanimprovethehardnessandcreepmodulusofUHMWPE/BHAcomposites,anddecreasetheirwearratesunderbovinesynovialubrication.WhenthecontentofBHAfillerparticleswasupto30wt%,UHMWPE/BHAcompositesdemonstratedthewelldesignperformancesofthesurfaceandbiotribologicalproperties.Fatigue,ploughingandslightadhesivewearwerethemainwearmechanismsforUHMWPEanditscomposites.Inaddition,thesizesofwearparticlesbecamelargerwithanincreaseinBHApowderaddition.TheseresultssuggestthatBHAfillerisadesirablecomponenttoincreasethewearresistanceofUHMWPE/BHAcompositesforbiomedicalapplications.

简介：摘要氧化锆全瓷材料在口腔医学领域应用广泛，但目前的加工流程难以制作精细结构。3D打印技术可加工复杂零件、降低消耗、缩短时间。本研究应用SLA对3YSZ进行成型、应用HIP进行后处理，对所获得试件的内部结构和力学性能进行测量。实验结果表明联合应用SLA和HIP可获得内部结构较为均匀的3YSZ产品，且力学性能初步达到牙科瓷材料的要求。

简介：客观：为了评估Porthsmouth的适用性，在预言经历新潮的联合关节造形术的病人的死亡为死亡和病态(P负鼠)的枚举修改了生理、起作用的严厉分数。方法：A总数of141病人(75男性和66女性，变老63.22年±一般水准上的14.45年)在2002年1月和2005年3月期间经历新潮的联合关节造形术与P-POSSUM.Their平均生理的分数回顾地被学习，起作用的严厉分数分别地是17.48±5.16和12.43±3.05。有P负鼠的预言的手术后的死亡与观察价值相比。亚群分析被执行调查P负鼠的预兆的能力。POSSUMscoring系统被用作控制。结果：三个病人实际上在这研究在操作以后死了。平均生理的分数在幸存组是在死亡组和17.16±4.56的32.33±9.87。前者显然比后者高，它显示出二个组之间的统计差别(Wilcoxon等级和测试，P<0.05)。同意在观察死亡数字和预言的死亡数字之间被发现的完成式由P负鼠计算了(2测试的Cochran-Mantel-Haenszelχ~，P>0.05)，不过，负鼠过高估计全面mortality.Conclusions；P负鼠能在经历新潮的联合关节造形术的病人精确地预言死亡，它比负鼠优异。

简介：CastingtitaniumalloyTC4(ZTC4)afterhotisostaticpressing(HIP)isoneofthepreferredmaterialsinthefieldofaerospacemanufacturing.Inthispaper,HIPZTC4afteralong-termthermalexposurewasinvestigated.Inordertoevaluatethevariationofmechanicalpropertieswithservicetime,thetensilepropertiesofthisalloyafterexposureat400°Cfor100,500,and1,000hwereinvestigated.Microstructureofsampleswasobservedbythemeansofopticalmicroscopy(OM),scanningelectronmicroscopy(SEM),andtransmissionelectronmicroscopy(TEM).Tensiletestwascarriedoutunderdifferenttesttemperaturesandfractureappearancewasstudied.Theresultsshowthatthestrengthincreaseswithexposuretimeduetothehardera2(Ti3Al)phaseprecipitatedintheaphaseandsuperficialoxygenlayerformed,whichresultsinthefactthattheresistanceofcrackpropagationcouldbeincreasedandcracksfirstinitiatebetweensurfaceoxidationandthematrix.Besides,thetensiletemperaturealsohasasignificanteffectonthemechanicalpropertiesofHIPZTC4.Theyieldstrengthandtensilestrengthdecreasewiththeincreaseoftensiletemperature,whilethetotalelongationincreases.

简介：Fourdifferentstructuralmodelsofartificialjointsweredevelopedandthefiniteelementmethod(FEM)wasemployedtoinvestigatetheirmechanicalcharacteristicsunderstaticanddynamicconditions.ThematerialsusedintheFEMcalculationwereultra-highmolecularweightpolyethylene(UHMWPE),316Lstainlesssteel,CoCrMoalloyandTi6Al4Valloy.Thestressdistribution,strain,andelasticdeformationunderstaticanddynamicconditionswereobtained.Analysisandcomparisonofthecalculationresultsofdifferentmodelswereconducted.Itisshownthatwiththesameparametersthemodelofametallicfemurheadcoveredwithanartificialcartilagelayerismoresimilartothestructureofthenaturalhumanjointanditsmechanicalcharacteristicsarethebestofthefourmodels.

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简介：AbstractPurpose:The COVID-19 pandemic has caused 1.4 million deaths globally and is associated with a 3-4 times increase in 30-day mortality after a fragility hip fracture with concurrent COVID-19 infection. Typically, death from COVID-19 infection occurs between 15 and 22 days after the onset of symptoms, but this period can extend up to 8 weeks. This study aimed to assess the impact of concurrent COVID-19 infection on 120-day mortality after a fragility hip fracture.Methods:A multi-centre prospective study across 10 hospitals treating 8% of the annual burden of hip fractures in England between 1st March and 30th April, 2020 was performed. Patients whose surgical treatment was payable through the National Health Service Best Practice Tariff mechanism for "fragility hip fractures" were included in the study. Patients’ 120-day mortality was assessed relative to their perioperative COVID-19 status. Statistical analysis was performed using SPSS version 27.Results:A total of 746 patients were included in this study, of which 87 (11.7%) were COVID-19 positive. Mortality rates at 30- and 120-day were significantly higher for COVID-19 positive patients relative to COVID-19 negative patients (p < 0.001). However, mortality rates between 31 and 120-day were not significantly different (p = 0.107), 16.1% and 9.4% respectively for COVID-19 positive and negative patients, odds ratio 1.855 (95% CI 0.865-3.978).Conclusion:Hip fracture patients with concurrent COVID-19 infection, provided that they are alive at day-31 after injury, have no significant difference in 120-day mortality. Despite the growing awareness and concern of "long-COVID" and its widespread prevalence, this does not appear to increase mediumterm mortality rates after a hip fracture.

简介：Background:Thegreatertrochantermarkeriscommonlyusedin3-dimensional(3D)models;however,itsinfluenceonhipandkneekinematicsduringgaitisunclear.Understandingtheinfluenceofthegreatertrochantermarkerisimportantwhenquantifyingfrontalandtransverseplanehipandkneekinematics,parameterswhichareparticularlyrelevanttoinvestigateinindividualswithconditionssuchaspatellofemoralpain,kneeosteoarthritis,anteriorcruciateligament(ACL)injury,andhippain.Theaimofthisstudywastoevaluatetheeffectofincludingthegreatertrochanterintheconstructionofthethighsegmentonhipandkneekinematicsduringgait.Methods:3Dkinematicswerecollectedin19healthysubjectsduringwalkingusingasurfacemarkersystem.Hipandkneeangleswerecomparedacrosstwothighsegmentdefinitions(withandwithoutgreatertrochanter)attwotimepointsduringstance:peakkneeflexion(PKF)andminimumkneeflexion(MinKF).Results:Hipandkneeanglesdifferedinmagnitudeanddirectioninthetransverseplaneatbothtimepoints.Inthethighmodelwiththegreatertrochanterthehipwasmoreexternallyrotatedthaninthethighmodelwithoutthegreatertrochanter(PKF:-9.34°±5.21°vs.1.40°±5.22°,MinKF:-5.68°±4.24°vs.5.01°±4.86°;p<0.001).Inthethighmodelwiththegreatertrochanter,thekneeanglewasmoreinternallyrotatedcomparedtothekneeanglecalculatedusingthethighdefinitionwithoutthegreatertrochanter(PKF:14.67°±6.78°vs.4.33°±4.18°,MinKF:10.54°±6.71°vs.-0.01°±2.69°;p<0.001).Smallbutsignificantdifferencesweredetectedinthesagittalandfrontalplaneanglesatbothtimepoints(p<0.001).Conclusion:Hipandkneekinematicsdifferedacrossdifferentsegmentdefinitionsincludingorexcludingthegreatertrochantermarker,especiallyinthetransverseplane.Thereforewhenconsideringwhethertoincludethegreatertrochanterinthethighsegmentmodelwhenusingasurfacemarkerstocalculate3Dkinematicsformovementassessment,iti

简介：针对无线传感中的节点定位不准确的问题,分析了目前的DV-HOP算法的三个步骤中存在的问题,然后将加权质心算法和二维双曲线概念引入到算法中,将校正值计算通过加权质心算法,将接受信号RSS作为参考的标准,有效地减少误差,同时针对距离估算问题采用了改进的二维双曲线算法,在二维双曲线的基础上引入权值概念,使得估算的距离更加精确。仿真实验表明,该算法使校正值定位误差,最大估算上的误差精度都有一定程度的降低,从整体效果上看相比于文献算法有了明显的提高,在一定程度上提高了定位的精度。

简介：AbstractBackground:Perioperative neurocognitive disorders (PND) are a series of severe complications in the perioperative and anesthetic periods with a decline in memory, execution ability, and information processing speed as the primary clinical manifestation. This study aimed to evaluate the impact of edaravone (EDA) on PND and peripheral blood C-X-C motif chemokine ligand 13 (CXCL13) levels in elderly patients with hip replacement.Methods:A total of 160 elderly patients undergoing hip arthroplasty in Affiliated Dongguan People’s Hospital of Southern Medical University (from March 2016 to March 2018) were randomly and double-blindly categorized into an EDA group and a control group (CON). Group EDA was administered intravenously EDA 30 min before surgery, and group CON was administered intravenously saline. The cognitive function of the two groups was evaluated 1-day before the operation and at 1 and 12 months after surgery, and the incidence of post-operative delirium was tested on days 1, 3, and 7 after surgery using the Chinese version of the confusion assessment method. Serum CXCL13 and interleukin (IL)-6 concentrations were measured before anesthesia, during surgery (30 min after skin incision), and on days 1, 3, and 7 after surgery. The continuous variables in accordance with normal distribution were tested using the Student’s t test, the continuous variables without normal distribution using the Mann-Whitney U test, and categorical variables by the χ2 test or Fisher exact test.Results:The incidence of post-operative delirium within 7 days after surgery was significantly higher in group CON than that in group EDA (31.3% vs. 15.0%, t=-5.6, P < 0.001). The modified telephone interview for cognitive status and activities of daily life scores were significantly higher in the group EDA than those in the group CON at 1 month (39.63 ± 4.35 vs. 33.63 ± 5.81, t = -2.13, P < 0.05 and 74.3 ± 12.6 vs. 61.2 ± 13.1, t = -1.69, P < 0.05) and 12 months (40.13 ± 5.93 vs. 34.13 ± 5.36, t = -3.37, P < 0.05 and 79.6 ± 11.7 vs. 65.6 ± 16.6, t= -2.08, P < 0.05) after surgery; and the incidence of neurocognitive dysfunction was significantly lower in the group EDA than that in the group CON (P < 0.05). Serum CXCL13 and IL-6 concentrations were significantly lower in the group EDA than those in the group CON during and after surgery (P < 0.05).Conclusion:EDA can significantly reduce the serum concentrations of CXCL13 and IL-6 and improve the PND of patients.

简介：AbstractBackground:Intravertebral and general anesthesia (GA) are two main anesthesia approaches but both have defects. This study was aimed to evaluate the effect of subarachnoid anesthesia combined with propofol target-controlled infusion (TCI) on blood loss and transfusion for total hip arthroplasty (THA) in elderly patients in comparison with combined spinal-epidural anesthesia (CSEA) or GA.Methods:Totally, 240 patients (aged ≥65 years, American Society of Anesthesiologists [ASA] I-III) scheduled for posterior THA were enrolled from September 1st, 2017 to March 1st, 2018. All cases were randomly divided into three groups to receive CSEA (group C, n = 80), GA (group G, n = 80), or subarachnoid anesthesia and propofol TCI (group T, n= 80), respectively. Primary outcomes measured were intra-operative blood loss, autologous and allogeneic blood transfusion, mean arterial pressure at different time points, length of stay in post-anesthesia care unit (PACU), length of hospital stay, and patient satisfaction degree. Furthermore, post-operative pain scores and complications were also observed. The difference of quantitative index between groups were analyzed by one-way analysis of variance, repeated measurement generalized linear model, Student-Newman-Keuls test or rank-sum test, while ratio index was analyzed by Chi-square test or Fisher exact test.Results:Basic characteristics were comparable among the three groups. Intra-operative blood loss in group T (331.53 ± 64.33 mL) and group G (308.03 ± 64.90 mL) were significantly less than group C (455.40 ± 120.48 mL, F = 65.80, P < 0.001). Similarly, the autologous transfusion of group T (130.99 ± 30.36 mL) and group G (124.09 ± 24.34 mL) were also markedly less than group C (178.31 ± 48.68 mL, F= 52.99, P < 0.001). The allogenetic blood transfusion of group C (0 [0, 100.00]) was also significantly larger than group T (0) and group G (0) (Z = 2.47, P = 0.047). Except for the baseline, there were significant differences in mean arterial blood pressures before operation (F= 496.84, P < 0.001), 10-min after the beginning of operation (F = 351.43, P < 0.001), 30-min after the beginning of operation (F = 559.89, P < 0.001), 50-min after the beginning of operation (F = 374.74, P < 0.001), and at the end of operation (F= 26.14, P < 0.001) among the three groups. Length of stay in PACU of group T (9.41 ± 1.19 min) was comparable with group C (8.83 ± 1.26 min), and both were significantly shorter than group G (16.55 ± 3.10 min, F = 352.50, P < 0.001). There were no significant differences among the three groups in terms of length of hospitalization and post-operative visual analog scale scores. Patient satisfaction degree of group T (77/80) was significantly higher than group C (66/80, χ2= 7.96, P = 0.004) and G (69/80, χ2 = 5.01, P = 0.025). One patient complained of post-dural puncture headache and two complained of low back pain in group C, while none in group T. Incidence of post-operative nausea and vomiting in group G (10/80) was significantly higher than group T (3/80, χ2 = 4.10, P = 0.043) and group C (2/80, χ2 = 5.76, P = 0.016). No deep vein thrombosis or delayed post-operative functional exercise was detected.Conclusions:Single subarachnoid anesthesia combined with propofol TCI seems to perform better than CSEA and GA for posterior THA in elderly patients, with less blood loss and peri-operative transfusion, higher patient satisfaction degree and fewer complications.

简介：AbstractBackground:Geriatric hip fracture patients receiving clopidogrel are a surgical challenge. In China, most of these patients undergo delayed surgical treatment after clopidogrel withdrawal for at least 5 to 7 days. However, delayed surgery is associated with increased complications and mortality in the older adults. This retrospective paralleled comparison study investigated the safety of early surgery for geriatric hip fracture patients within 5 days of clopidogrel withdrawal.Methods:Acute hip fracture patients (≥65 years) who were hospitalized in the orthogeriatric co-management ward of Beijing Jishuitan Hospital between November 2016 and April 2018 were retrospectively reviewed. Sixty patients taking clopidogrel before injury and discontinued <5 days before surgery constituted the clopidogrel group. The control group constituted 60 patients not taking antiplatelet or anticoagulant drugs and matched 1:1 with the clopidogrel group for sex, fracture type, operative procedure, and time from injury to operation (±10 h). The primary outcome was perioperative blood loss and the secondary outcomes were transfusion requirement, complications, and mortality. The Student’s t test or Wilcoxon signed rank sum test was used for continuous variables and the Chi-square test was used for categorical variables.Results:Age, body mass index, American Society of Anesthesiologists score, and percentage undergoing general anesthesia were comparable between the groups (P > 0.050). The percentages of patients with coronary heart disease (61.7% vs. 18.3%; P < 0.001) and cerebrovascular disease (45.0% vs. 15.0%; P < 0.010) were significantly higher in the clopidogrel vs. control groups, respectively. The median clopidogrel discontinuation time before operation was 73.0 (range: 3.0-120.0) h. There was no significant difference in the estimated perioperative blood loss between the clopidogrel group (median: 745 mL) and control group (median: 772 mL) (P = 0.866). The intra-operative transfusion rate was higher in the clopidogrel group (22/60, 36.7%) than that in the control group (12/60, 20.0%) (P < 0.050). However, there was no significant difference in the blood transfusion rate during the entire perioperative period (26/60, 43.3% vs. 20/60, 33.3%; clopidogrel group vs. control group, respectively; P > 0.050). There was no significant difference in perioperative complications, and 30-day and 1-year mortality rates between the groups.Conclusions:Early hip fracture surgery is safe for elderly patients within 5 days of clopidogrel withdrawal, without increased perioperative blood loss, transfusion requirement, complications, and mortality compared with patients not taking antiplatelet drugs.

简介：AbstractPurpose:By comparing the outcomes of total hip arthroplasty with hemiarthroplasty in elderly patients with a femoral neck fracture to investigate the one-year mortality, dislocation, infection, reoperation rate, and thromboembolic event.Methods:The PubMed, EMBASE databases, and Cochrane library were systematically searched from the inception dates to April 1, 2020 for relevant randomized controlled trials in English language using the keywords: "total hip arthroplasty" , "hemiarthroplasty" and "femoral neck fracture" to identify systematic reviews and meta-analyses. Two reviewers independently selected articles, extracted data, assessed the quality evidence and risk bias of included trials using the Cochrane Collaboration’ stools, and discussed any disagreements. The third reviewer was consulted for any doubts or uncertainty. We derived risk ratios and 95% confidence intervals. Mortality was defined as the primary outcome. Secondary outcomes were other complications, dislocation, infection, reoperation rate, and thromboembolic event.Results:This meta-analysis included 10 studies with 1419 patients, which indicated that there were no significant differences between hemiarthroplasty and total hip arthroplasty in reoperation, infection rate, and thromboembolic event. However, there was a lower mortality and dislocation rate association with total hip arthroplasty at the one-year follow-up.Conclusion:Based on our results, we found that total hip arthroplasty was better than hemiarthroplasty for a hip fracture at one-year follow-up.