甲强龙联合脂多糖诱导成年犬股骨头动-静脉系统的组织病理学特点

背景:糖皮质激素类的诸多作用机制对于与骨坏死的病理过程的启动有密切关系,然而对于激素性骨坏死时股骨头动、静脉血管在不同时段发生的病理形态学变化的区别仍缺少相关记述。目的:观察大剂量皮质激素联合脂多糖诱导下的成年犬在不同时段其动脉和静脉系统的组织病理形态学变化,以讨论这种变化对骨坏死发生和发展造成的可能影响。方法:将健康成年犬15只随机分为4,8周观察组及对照组,每组5只(10髋)。4,8周观察组行静脉注射脂多糖10 g/kg,于24 h后肌注甲强龙20 mg/kg,连续注射3次,每次间隔24 h,干预后4,8周麻醉处死,取股骨头行双侧病理切片染色,对骨内及支持带动静脉血管缩窄度进行分析测量。结果与结论:诱导4,8周后,犬骨内静脉的结构形态发生明显变化,表现为正常型静脉结构显著减少,而中度狭窄型、阻塞塌陷型静脉结构占比显著升高。在骨内动脉系统,8周观察组相对其他2组骨内区域动脉血管内膜相对增厚,血管缩窄程度高(P<0.05)。结果证实,在皮质激素联合脂多糖诱导下,成年犬股骨头动脉和静脉系统出现病理变化的时间节点存在差异。静脉系统在药物诱导早期(4周)最先呈现出病理变化,而动脉系统病理变化出现在药物诱导8周后。

髋臼缺损程度对成人髋关节应力影响的三维有限元分析

背景:髋臼缺损是成人髋关节发育不良的典型特征之一。髋臼缺损导致其对股骨头包容不足,二者间接触面积减少,局部压强增大,久之势必造成髋关节磨损加快,导致关节炎甚至关节脱位的发生。但何种程度缺损才会导致髋关节生物力学改变,还没有公认的客观标准。目的:应用三维有限元方法分析不同程度髋臼缺损对髋关节周围应力分布的影响,为临床治疗髋关节发育不良提供理论指导。方法:选取正常成人髋关节CT薄层扫描数据,利用Mimics15.0和Hypermesh软件去除髋臼外缘部分骨性结构,模拟建立伴有不同程度骨缺损髋关节发育不良患者模型。以Ansys10.0加载关节负荷,分析单足着地情况下髋关节软骨下骨Von Mises应力分布情况。结果与结论:各组模型计算结果与实际情况相符合,髋臼和股骨的最大Von Mises应力值出现在髋臼顶穹部及股骨颈后内侧;当模拟单腿站立时,其应力峰值随着CE角变小而增大,由CE角30°时的2.768 MPa和3.029 MPa增加到5°时的11.075 MPa和15.322 MPa。CE角小于15°时该变化趋势更明显。提示髋臼缺损加大髋关节周围应力峰值,且缺损程度越大该影响越大,因而建议对于髋臼缺损患者尽早进行临床干预。

纳滤膜分离技术在废水处理中的应用

对纳滤膜分离技术进行概述,对纳滤膜分离技术在废水处理中的应用以及纳滤膜分离技术的发展进行了展望。以期望对纳滤膜分离技术在废水处理中的应用效率提升有所帮助。

Biomechanical comparison of double-row versus transtendon single-row suture anchor technique for repair of the grade III partial articular-sided rotator cuff tears

Background For partial-thickness tears of the rotator cuff, double-row fixation and transtendon single-row fixation restore insertion site anatomy, with excellent results. We compared the biomechanical properties of double-row and transtendon single-row suture anchor techniques for repair of grade Ⅲ partial articular-sided rotator cuff tears.Methods In 10 matched pairs of fresh-frozen sheep shoulders, the infraspinatus tendon from 1 shoulder was repaired with a double-row suture anchor technique. This comprised placement of 2 medial anchors with horizontal mattress sutures at an angle of .≤45° into the medial margin of the infraspinatus footprint, just lateral to the articular surface, and 2 lateral anchors with horizontal mattress sutures. Standardized, 50% partial, articular-sided infraspinatus lesions were created in the contralateral shoulder. The infraspinatus tendon from the contralateral shoulder was repaired using two anchors with transtendon single-row mattress sutures. Each specimen underwent cyclic loading from 10 to 100 N for 50 cycles, followed by tensile testing to failure. Gap formation and strain over the footprint area were measured using a motion capture system; stiffness and failure load were determined from testing data.Results Gap formation for the transtendon single-row repair was significantly smaller （P 〈0.05） when compared with the double-row repair for the first cycle （（1.74±0.38） mm vs. （2.86±0.46） mm, respectively） and the last cycle （（3.77±0.45） mm vs. （5.89±0.61） mm, respectively）. The strain over the footprint area for the transtendon single-row repair was significantly smaller （P 〈0.05） when compared with the double-row repair. Also, it had a higher mean ultimate tensile load and stiffness.Conclusions For grade Ⅲ partial articular-sided rotator cuff tears, transtendon single-row fixation exhibited superior biomechanical properties when compared with double-row fixation.

Effect of superior retinacular artery damage on osteonecrosis of the femoral head

Background Osteonecrosis of the femoral head （ONFH） is the result of dysfunctional blood supply, but associations between specific damaged arteries, imaging changes and clinical sign require more understanding. We investigated characteristics of ONFH that pertain to blood supply, imaging appearance, and clinical feature to judge the prognosis of ONFH.