H亚型血管与骨质疏松症

目前,骨质疏松症的传统治疗方法主要集中于抑制骨破坏和促进骨形成方面,但此单一的治疗方法很难彻底解决多重因素致病的骨质疏松症。近来,许多文献报道血管形成与骨形成之间存在偶联关系,其中骨骼中新发现的H亚型血管成为骨质疏松治疗的新焦点。根据骨骼血管内皮细胞位置和功能的区别,可分为H亚型血管和L亚型血管,而H亚型血管可促进其周围骨祖细胞的分化与增殖。H亚型血管主要分布于干骺端和骨膜下,表现为血小板-内皮细胞粘附分子抗体(CD31)和内皮粘蛋白抗体(endomucin,EMCN)强阳性;而L亚型血管表现为两种内皮细胞抗体(CD31或EMCN)弱阳性,分布于骨干区。实验表明,H亚型内皮细胞与周围的骨祖细胞数量会随着小鼠的老龄化呈正比例下降,而且小鼠体内缺氧诱导型转录因子1α缺失后会出现H亚型内皮细胞和骨祖细胞数量明显降低,这些均提示H亚型血管与骨形成存在偶联关系。笔者着重对H亚型内皮细与骨形成之间存在的偶联关系及其机制进行综述,探讨H亚型内皮细胞与骨质疏松症的关系,以进一步加深对骨质疏松症发生、发展的认识,为骨质疏松症治疗提供新的思路与方法。     

Laparoscopic myomectomy—an unusual cause of meralgia paresthetica

Meralgia paresthetica may be associated with diabetes, trauma, infection, and use of self-retaining retractors. Our patient experienced left upper thigh paresthesia after undergoing laparoscopic myomectomy with extensive dissection of the left retroperitoneal space. Neurologic evaluation confirmed meralgia paresthetica. The patient was observed for 4 months, by which time the neuropathy resolved spontaneously.     

Finite Element Analysis of Mobile-bearing Unicompartmental Knee Arthroplasty: The Influence of Tibial Component Coronal Alignment

Background:

Controversies about the rational positioning of the tibial component in unicompartmental knee arthroplasty (UKA) still exist. Previous finite element (FE) studies were rare, and the results varied. This FE study aimed to analyze the influence of the tibial component coronal alignment on knee biomechanics in mobile-bearing UKA and find a ration range of inclination angles.

Methods:

A three-dimensional FE model of the intact knee was constructed from image data of one normal subject. A 1000 N compressive load was applied to the intact knee model for validating. Then a set of eleven UKA FE models was developed with the coronal inclination angles of the tibial tray ranging from 10° valgus to 10° varus. Tibial bone stresses and strains, contact pressures and load distribution in all UKA models were calculated and analyzed under the unified loading and boundary conditions.

Results:

Load distribution, contact pressures, and contact areas in intact knee model were validated. In UKA models, von Mises stress and compressive strain at proximal medial cortical bone increased significantly as the tibial tray was in valgus inclination >4°, which may increase the risk of residual pain. Compressive strains at tibial keel slot were above the high threshold with varus inclination >4°, which may result in greater risk of component migration. Tibial bone resection corner acted as a strain-raiser regardless of the inclination angles. Compressive strains at the resected surface slightly changed with the varying inclinations and were not supposed to induce bone resorption and component loosening. Contact pressures and load percentage in lateral compartment increased with the more varus inclination, which may lead to osteoarthritis progression.

Conclusions:

Static knee biomechanics after UKA can be greatly affected by tibial component coronal alignment. A range from 4° valgus to 4° varus inclination of tibial component can be recommended in mobile-bearing UKA.     

骨陷窝-微管代谢和生理功能的研究应用与进展

BACKGROUND: Interstitial fluid flow around the osteocytes caused by a series of physiological activities plays an important role in the osteocyte metabolism and signal transduction. OBJECTIVE: To review and summarize the research progress of bone structures and physiological functions, then further illustrate how the mechanical loads make an impact on bone tissue. METHODS: A computer-based search was conducted in PubMed database for articles related to the bone microstructure, metabolism and osteocyte signal transduction published from January 2009 to December 2015. The keywords were “osteocyte, mechanical load, permeability, lacunar-canalicular system, interstitial fluid flow, mechanotransduction, signaling pathways” in English. Data were screened firstly, dated articles or literatures with wrong research methods were excluded, and totally 40 eligible articles were enrolled. RESULTS AND CONCLUSION: Bone tissue can quickly adapt to the change of mechanical environment to guarantee enough osteocytes in the functional bone area indicating that osteocytes regulate the bone absorption and formation by responding to stress, which is closely related to osteocyte physiological characters. Osteocytes exist in mineralized matrix, and the special microstructures make it possible to receive mechanical loads and transform the mechanical signals into chemical signals aimed at regulating the bone absorption or formation.So the interstitial fluid flow in the lacuna-canalicular system occures, namely load-induced fluid flow, when the mechanical load is distributed on the bone. This fluid flow affects the bone tissue through two mechanisms: regulating osteocyte metabolism and participating in the mechanotransduction. In conclusion, the mechanical load plays a vital role in maintaining health bone and regulating bone adaptation. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Ability of lower teardrop edge to restore anatomical hip center height in total hip arthroplasty

Background The acetabular teardrop is often used to guide acetabular component placement in total hip arthroplasty （THA）.Placing the lower acetabular component aspect at the same level as the lower teardrop edge was assumed to restore the hip center of rotation.Here we radiographically analyzed the relationship between cup center and normal contralateral acetabulum center height on unilateral THA using this placement method.Methods A total of 106 unilateral THA cases with normal contralateral acetabula were reviewed and the vertical and horizontal distances in relation to the lower acetabular teardrop edge from both hip joint centers,cup inclination,and anteversion were measured radiographically.The paired t-test was used to compare left and right hip center heights.Scatter plots and Pearson＇s correlation coefficients were used to evaluate differences in hip center heights,cup anteversion,inclination angles,and medialized cup center distance compared to the contralateral hip joint.Results Cup center height was significantly greater （P ＜0.01） than contralateral hip joint center height （93.4％ in the 0-5 mm range,6.6％ ＞5 mm）.There was a weak correlation between hip center height difference and inclination （r=0.376,P ＜0.01） and between difference and anteversion （r=0.310,P ＜0.01） but no correlation between difference and outer cup diameter （r=0.184,P=0.058） or difference and medialized cup center distance （r＝-0.098,P=0.318）.Conclusions Although this method did not exactly replicate anatomic hip center height,the clinical significance of cup center height and anatomic hip center height differences is negligible.This acetabular component placement method has high simplicity,reliability,and stability.     

活动平台单髁膝关节置换胫骨后倾的有限元分析

背景：目前单髁膝关节置换中胫骨假体后倾角度的选择存在较多争议,相关的生物力学研究较少。 目的：通过有限元分析结果寻求活动平台单髁膝关节置换中合理胫骨后倾的角度。 方法：运用三维重建技术及有限元前处理技术建立正常膝关节有限元模型,并进行验证,在此基础上建立不同胫骨假体后倾角度的单髁膝关节置换有限元模型,统一边界条件和载荷,行有限元分析。 结果与结论：成功建立了不同胫骨后倾角度的单髁膝关节置换有限元模型,分析结果发现增大胫骨假体后倾可使胫骨后内侧皮质及松质骨应力逐渐增加,且增大了外侧间室载荷和软骨接触应力,而胫骨前倾使胫骨前内侧皮质应力明显增加。推荐活动平台单髁膝关节置换中选择0°-7°胫骨假体后倾。 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

人股骨头骨微血管内皮细胞的分离培养方法

目的:探讨培养人股骨头骨微血管内皮细胞分离培养方法.方法:2013年10月至2014年1月15例行髋关节置换患者切除的内部无病变的股骨头,男2例,女13例;年龄38～92岁,平均71.2岁.无菌条件下将股骨头内松质骨咬成碎骨粒,放入培养基.采用酶消化法,密度梯度离心法分离细胞;差速贴壁法,选择性培养基法纯化细胞.倒置显微镜观察细胞特点,并采用vWF、CD31免疫荧光进行细胞鉴定.结果:原代培养24 h后倒置显微镜下观察细胞数量与患者年龄呈正相关,年龄越大细胞越少.培养4～5 d细胞呈短梭形、多角形或“鹩卵石”状.培养7～10d细胞生长密集,细胞融合呈漩涡状,接触抑制明显.vWF、CD31免疫荧光检测阳性率100％,表明细胞为骨微血管内皮细胞.结论:人股骨头骨微血管内皮细胞分离培养方法简单、稳定、有效、可重复性好,可以获得纯度较高的股骨头骨微血管内皮细胞.