Numerical investigation of mechanical effects caused by various fixation positions on a new radius intramedullary nail

Fracture of the radius diaphysis is an unusual injury in adults. Open reduction and plate osteosynthesis has been recommended by most of the authors. However, this trend has started to change with the recent introduction of newly designed interlocking intramedullary (IM) nails. New generation of IM nails are developed in order to utilise the advantages of IM nails against plates. Because of its anatomical structure, the radius bone has a complex geometry. Therefore, the callus structure, which forms during the healing period, should not be affected from external effects, such as excessive loads or motion. In this study, effects of radial styloid process (RSP), dorsal side and ulnar notch edge fixations of a new design radius IM nail on the healing period were numerically investigated. A three-dimensional solid model of radius was obtained from computed tomography images of a volunteer and callus structure model, was placed accordingly and different fixations of implants were performed. The models were analysed under axial loads transferring from the wrist to the radius bone using finite element method. As a result of the analysis, fixation of IM nail from RSP was found to be beneficial on healing period in terms of both callus motion and emerging stresses.     

Recanalisation of coronary chronic total occlusions with new techniques including the retrograde approach via collaterals

Objective

Percutaneous treatment of coronary chronic total occlusions (CTO) remains one of the major challenges in interventional cardiology. The strategies of recanalisation in CTO have changed drastically due the development of new techniques such as the retrograde approach via collaterals. In this single-centre experience we sought to analyse the success rates with the use of different CTO techniques, the complication rates, and we evaluated predictors of failed CTO recanalisation attempts.

Methods and Results

In this single-centre observational study we analysed the prospectively entered data of 331 consecutive patients, undergoing percutaneous coronary intervention (PCI) for CTO in 338 lesions at the Heart Center Wuppertal between June 2007 and July 2010. Nineteen lesions were attempted twice and one lesion three times (=358 procedures). The lesion-related success rates were 81.1%. Single-wire usage was the predominant strategy used in 198 antegrade cases (65.6%) followed by parallel wire technique and see-saw technique in 94 cases (31.1%). In the retrograde procedures, the reverse CART technique was predominantly used (35.7%), followed by retrograde wire passage (17.9%), marker wire (17.9%) and CART (14.3%). The in-hospital complications were low and comparable with conventional PCI data. The presence of blunt stump, severe calcification, severe tortuosity and occlusion length >30 mm were independent predictors of procedural failure.

Conclusions

A high degree of success with low in-hospital complications comparable with conventional PCI data can be expected in the hands of experienced CTO operators. A second try with a retrograde approach after antegrade failure should be considered.     

Comparison of the clinical effect of DHS and PFNA on senile osteoporotic fracture and their significance of changes in BALP expression level

Objective:To investigate the clinical effects of dynamic hip screw (DHS) and proximal femoral nail anti-rotation (PFNA) on senile osteoporosis patients and their effects on the expression level of bone-specific alkaline phosphatase (BALP).Methods:116 elderly patients with osteoporotic fracture were divided into DHS group (n=67) and PFNA group (n=49). BALP values were measured by ELISA before operation and 30 days after operation.Results:The operation time, the bleeding volume, and the weight-bearing time of PFNA group was shorter than DHS group (p<0.05); the dominant blood loss and occult blood loss in PFNA group were less than those in DHS group (p<0.05); the healing time and detumescence time, the complications of PFNA group was fewer than the DHS group (p<0.05). The ten-meter walking speed and the five sitting tests in PFNA group were shorter than that in DHS group (p<0.05); the excellent and good rate and Harris score in PFNA group were higher than those in DHS group (p<0.05). The expression of BALP in PFNA group was lower than that in DHS group (p<0.05).Conclusion:PFNA surgery has less trauma, fewer complications, more optimistic postoperative healing and recovery degree, and is more conducive to the reduction of BALP expression level.     

Clathrin-independent endocytosis,retrograde trafficking,and cell polarity

Several mechanisms allow for cargo internalization into cells within membrane-bound endocytic carriers. How these internalization processes couple to specific pathways of intracellular distribution remains poorly explored. Here, we review uptake reactions that are independent of the conventional clathrin machinery. We discuss how these link to retrograde trafficking from endosomes to the Golgi apparatus and exemplify biological situations in which the polarized secretion capacity of the Golgi apparatus allows for retrograde cargoes to be delivered to specialized areas of the plasma membrane, such as the leading edge of migratory cells or the immunological synapse of immune cells. We also address the evidence that allows to position apicobasal polarity of epithelial cells in this context. The underlying theme is thereby the functional coupling between specific types of endocytosis to intracellular retrograde trafficking for protein cargoes that need to be localized in a highly polarized and dynamic manner to plasmalemmal subdomains.     

交锁髓内钉与锁定加压钢板内固定对股骨干骨折患者膝关节功能及创伤相关指标的影响

目的:探讨交锁髓内钉(IIN)与锁定加压钢板(LCP)两种内固定方法对股骨干骨折(FSF)患者膝关节功能及创伤相关指标的影响。方法:回顾性分析2015年1月-2018年3月我院收治的97例FSF患者的临床资料,依照内固定方式的不同分为IIN组(n=54)和LCP组(n=43),比较两组患者的术后骨折愈合情况,围术期指标、创伤相关指标、膝关节功能恢复及并发症情况。结果:术后IIN组骨折愈合优良率为92.59%,高于LCP组的76.74%(P0.05),IIN组患者手术时间、住院时间、术中出血量、术后引流量、骨折愈合时间少于LCP组(P0.05);IIN组浅表感染率、内固定物断裂率、骨折延迟愈合率、不愈合率及血清C反应蛋白(CRP)、去甲肾上腺素(NE)、肾上腺素(E)、超氧化物歧化酶(SOD)水平低于LCP组(P0.05);IIN组患者Fugl-Meyer下肢运动评分、美国膝关节协会(KSS)评分高于LCP组(P0.05)。结论:相较于LCP内固定,IIN内固定对FSF患者的创伤较轻,术后并发症较少,可更好地促进骨折愈合及膝关节功能恢复。     

A role for the Rab6B Bicaudal-D1 interaction in retrograde transport in neuronal cells

The Rab6 subfamily of small GTPases consists of three different isoforms: Rab6A, Rab6A' and Rab6B. Both Rab6A and Rab6A' are ubiquitously expressed whereas Rab6B is predominantly expressed in brain. Recent studies have shown that Rab6A' is the isoform regulating the retrograde transport from late endosomes via the Golgi to the ER and in the transition from anaphase to metaphase during mitosis. Since the role of Rab6B is still ill defined, we set out to characterize its intracellular environment and dynamic behavior. In a Y-2H search for novel Rab6 interacting proteins, we identified Bicaudal-D1, a large coiled-coil protein known to bind to the dynein/dynactin complex and previously shown to be a binding partner for Rab6A/Rab6A'. Co-immunoprecipitation studies and pull down assays confirmed that Bicaudal-D1 also interacts with Rab6B in its active form. Using confocal laser scanning microscopy it was established that Rab6B and Bicaudal-D1 co-localize at the Golgi and vesicles that align along microtubules. Furthermore, both proteins co-localized with dynein in neurites of SK-N-SH cells. Live cell imaging revealed bi-directional movement of EGFP-Rab6B structures in SK-N-SH neurites. We conclude from our data that the brain-specific Rab6B via Bicaudal-D1 is linked to the dynein/dynactin complex, suggesting a regulatory role for Rab6B in the retrograde transport of cargo in neuronal cells.     

Can a death signal half-life be used to sense the distance to a lesion site in axons?

Neuron response to injury depends on the distance to the lesion site, which means that neurons are capable of sensing this distance. Several mechanisms explaining how neurons can do this have been proposed and it is possible that neurons use a combination of several mechanisms to make such measurements. In this paper we investigate the feasibility of the simplest mechanism, which is based on the hypothesis that death signals, produced at the lesion site, propagate toward the neuron soma. The signals are propelled by dynein motors. If signals have a finite half-life, they decay as they propagate. By measuring the concentration of death signals arriving to the soma, neurons should thus be able to determine the distance to the injury site. We develop and solve a transport equation based on the above model. We investigate how a death signal distribution depends on the dynein velocity distribution. We evaluate the efficiency of such a mechanism by investigating the sensitivity of death signal concentration at the soma to the distance to the injury site. By using the hypothesis that system performance is optimized by evolution, we evaluate death signal half-lives that would maximize this sensitivity.     

Stress analysis of a centrally fractured rib fixated by an intramedullary screw

The stress on an intramedullary screw rib fixation device holding together a centrally fractured human rib under in vivo force loadings was studied using finite element analysis (FEA). Validation of the FEA modelling using pullout from porcine ribs proved FEA to be suitable for assessing the structural integrity of screw/bone systems such as rib fixated by a screw. In the human rib fixation investigation, it was found that intramedullary bioresorbable Bioretec screws can fixate centrally fractured human ribs under normal breathing conditions. However, under coughing conditions, simulation showed Bioretec fixating screws to bend substantially. High stresses in the screw are mainly the result of flexion induced by the force loading, and are restricted to thin regions on the outside of the screw shaft. Stiffer screws result in less locally intense stress concentrations in bone, indicating that bone failure in the bone/screw contact regions can be averted with improvements in screw stiffness.     

逆行交锁髓内钉联合单侧骨皮质锁定钢板固定治疗股骨髁上骨不连

目的:探讨逆行交锁髓内钉联合单侧骨皮质钢板固定治疗股骨髁上骨不连的临床疗效。方法:对25例股骨髁上骨不连,均采用逆行交锁髓内钉联合单侧骨皮质钢板固定加自体髂骨植骨治疗。结果:25例获12～24个月随访,平均12个月。4～8个月内均获骨性愈合。结论:应用逆行交锁髓内钉联合单侧骨皮质钢板固定后骨折端可获得坚强内固定,手术操作简便、安全,可早期进行膝关节和股四头肌功能锻炼,是一种治疗股骨髁上骨不连的有效方法。     

髓内钉InterTan 治疗股骨近端骨折的早期疗效分析

目的:分析应用新一代股骨近端髓内钉( InterTan)治疗股骨近端骨折的早期临床疗效.方法:回顾性分析2009年9月至201 1年8月我科共收治股骨近端骨折患者共107例,均采用InterTan髓内钉系统进行治疗,其中男45例,女62例;年龄34-93岁,平均73.05岁.受伤肢体左侧63例,右侧44例.按AO分型,31-A1型32例,31 -A2型59例,31-A3型16例.记录患者手术持续时间、并发症、死亡率、骨折愈合时间、末次复查Harris评分,并对比患者健侧及患侧术前、术中及术后1周的颈干角变化.所有数据采用SPSS 13.0进行统计分析.结果:平均手术持续时间为66.69分钟.颈干角:术前健侧:140.66±9.08度,术前患侧:118.00± 15.49度,术中患侧:135.16± 7.08度,术后1周患侧:137.51±15.21度.术前患侧颈干角与其他三组相比均有显著性差异(P＜0.05),术前健侧、术中复位后患侧、术后1周患侧颈干角之间相比均无显著性差异.3例患者于随访过程中死亡,6例患者失访.98例患者获得随访,随访时间3 -22个月,平均8.6个月.2例患者发生头钉切出,3例患者术后练习后出现股骨疼痛症状,未发生股骨干骨折.96例患者均获得骨性愈合,骨折愈合时间12～18周.临床疗效按Harris评分标准:41-92分,平均78.5分,优良率80.6％.结论:髓内钉InterTan是治疗股骨近端骨折的良好选择.