Similitude of cement-bone micromechanics in cemented rat and human knee replacement

A preclinical rat knee replacement model was recently developed to explore the biological and mechanobiological changes of trabecular resorption for cement-bone interdigitated regions. The goal here was to evaluate the relevance of this model compared with human knee replacement with regards to functional micromechanics. Eight nonsurvival, cemented knee replacement surgeries were performed, the interdigitated gap morphology was quantified, and interface micromotion between cement and bone was measured for 1 to 5 bodyweight loading. Computational fluid dynamics modeling of unit cell geometries with small gaps between trabeculae and cement was used to estimate fluid flow. Gap width (3.6 μm) was substantially smaller compared with cement-bone gaps reported in human knee replacement (11.8 μm). Micromotion at the cement-bone border was also decreased for the rat knee replacement (0.48 μm), compared with human (1.97 μm), for 1 bodyweight loading. However, the micromotion-to-gap width ratio (0.19 and 0.22 for, rat and human), and estimated fluid shear stress (6.47 and 7.13 Pa, for rat and human) were similar. Replicating the fluid dynamic characteristics of cement-bone interdigitated regions in human knee replacements using preclinical models may be important to recapitulate trabecular resorption mechanisms due to proposed supraphysiologic fluid shear stress. Statement of clinical significance: local cement-bone micromotion due to joint loading may contribute to the process of clinical loosening in total joint replacements. This work shows that while micromotion and gap morphology are diminished for the rat knee model compared to human, the motion-to-gap ratio, and corresponding fluid shear stress are of similar magnitudes     

Total Knee Arthroplasty with an Uncemented Trabecular Metal Tibial Component : A Registry-Based Analysis

Previous poor results have kept the appeal of uncemented total knee arthroplasties (TKAs) minimal. We analyzed the mid-term survivorship and reasons for failures of a contemporary uncemented porous tantalum monoblock tibial component nation-wide. During the study period (2003–2010), such tibial components were used in 1143 primary TKAs recorded in the Finnish Arthroplasty Registry. Seven-year survivorship of these TKAs was 100% (95% CI 99–100) with revision for aseptic loosening of the tibial component, and 97% (95% CI 96–98) with revision for any reason as the respective end points. The most common reasons for revisions were instability and prosthetic joint infections. In conclusion, TKAs using an uncemented porous tantalum monoblock tibial component showed excellent mid-term survivorship in a population-based setting.     

骨细胞形成过程中成纤维细胞生长因子受体3的调节作用及机制

文题释义： 失神经骨折：机体骨折合并有各类、各层面神经的损伤。随着社会经济的飞速发展,这类骨折的发生也逐年增多,在愈合过程中表现出较单纯骨折愈合加速且骨痂过量生长,甚至在肌肉中出现异位骨化,尤其是关节周围的骨折,严重影响关节功能和治疗效果,已成为修复重建和组织工程领域的研究热点。 创伤性神经损伤：包括创伤性颅脑损伤、脊髓损伤和周围神经损伤。这类损伤伴有骨折的患者表现出较单纯骨折愈合加速且骨痂过量生长,甚至在肌肉中出现异位骨化。 背景：在临床治疗中,创伤性神经损伤伴有骨折的患者表现出较单纯骨折愈合加速且骨痂过量生长,甚至在肌肉中出现异位骨化,严重影响这类骨折的治疗效果。对于影响失神经后骨折愈合加速的具体原因和机制,目前并不清楚。 目的：探索成纤维细胞生长因子受体3抑制剂在骨折愈合过程中的作用及表达变化规律。 方法：实验方案经兰州大学第二医院动物实验伦理委员会批准。选用60只雌性SD大鼠,制作坐骨神经损伤的胫骨横行骨折模型,随机分为实验组及对照组2组。实验组造模后腹腔注射成纤维细胞生长因子受体3阻滞剂;对照组造模后给等剂量生理盐水。分别于造模后4,7,10,14,21 d拍X射线片后取胫骨大体标本(每个时间点6只),取胫骨进行苏木精-伊红染色、Masson三色法染色组织学观察;计算大鼠胫骨骨细胞密度和骨小梁密度;测定胫骨组织纤维率。 结果与结论：①两组大鼠胫骨X射线观察差别不显著;②苏木精-伊红染色、Masson三色法染色结果显示实验组修复效果比对照组较好;③2组大鼠胫骨骨细胞密度、骨小梁密度及胫骨组织纤维率在7-14 d有明显差别(实验组>对照组);④抑制成纤维细胞生长因子受体3在周围神经失神经情况下能够加快骨折愈合,促进骨痂的塑形。成纤维细胞生长因子受体3在骨折后7-14 d时间段表达最为活跃。 ORCID: 0000-0002-7687-4383(许少策) 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

3D打印钛合金骨小梁多孔结构的拉伸性能

文题释义：3D打印：3D打印技术开创了增材制造的生产方式,即依照3D设计蓝图可将金属粉末等原材料逐层堆积而制成最终产品,擅长构建形状结构复杂的产品与个体化定制,制作特异性假体或植入物,供植入以达到重建等目的,在骨科领域得到了广泛应用。 钛合金骨小梁：是以钛合金粉末为原材料,采用金属3D打印技术通过金属微粒逐层熔融叠加生成的一种类人体骨小梁三维空间网孔结构,其力学性能和生物学性能和人体的松质骨骨小梁极为相似,作为人工植入假体的表面结构,具有非常出色的骨长入效果。 背景：3D打印钛合金多孔结构以其良好的机械性能和生物相容性已经在骨科植入假体设计与临床应用方面得到了快速发展,与涂层假体相比,钛合金骨小梁结构具有骨长入快和骨长入好的优点。为了保证骨科植入物的安全,目前多采用实验方式确定骨小梁结构的拉伸、剪切疲劳和弯曲疲劳强度。 目的：通过力学实验和有限元数值模拟方法研究骨小梁多孔结构的力学性能。 方法：①3D打印钛合金骨小梁拉伸试件实验：设计并制备3D打印钛合金骨小梁拉伸试件,骨小梁结构的丝径为0.28-0.35 mm、孔径为0.71 mm、孔隙率为73%。检测钛合金骨小梁结构的拉伸强度,分析其失效机制,同时分析不同打印位置对骨小梁拉伸强度的影响。②数值模拟实验：利用有限元方法建立包括骨小梁理论结构的拉伸试件实体模型,模拟骨小梁试件的拉伸破坏过程。 结果与结论：①3D打印钛合金骨小梁拉伸试件的极限载荷分布在39.55-47.11 kN之间,等效极限拉伸应力分布在62.79-74.53 MPa之间,拉伸破坏的结果为网状结构断裂,说明钛合金骨小梁具有较高的拉伸强度;②3D打印钛合金骨小梁拉伸试件实验与数值模拟实验均显示,骨小梁试件受到拉伸破坏时的破坏形式为丝径断裂,不会在骨小梁与钛合金实体的结合面发生断裂;③数值模拟实验中骨小梁试件的拉伸破坏载荷低于3D打印钛合金骨小梁拉伸试件,造成该差异的原因主要为：3D打印骨小梁试件的丝径(280-350 μm之间)大于骨小梁的理论丝径(142 μm),而孔径(孔隙率75%)小于骨小梁的理论孔径(孔隙率96%)。 ORCID: 0000-0001-7000-2093(张兰) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

Microstructural trabecular bone from patients with osteoporotic hip fracture or osteoarthritis: Its relationship with bone mineral density and bone remodelling markers

Osteoporosis (OP) and osteoarthritis (OA) are the most prevalent musculoskeletal disorders in the elderly but the relationship between them is unclear. The purposes of this study are to analyze the bone turnover markers (BTM), bone mineral density (BMD) and the structural and mechanical properties of trabecular bone in patients with OP and OA, and to explore the relationship between these two diseases. We studied 12 OP patients and 13 OA patients. We analyzed BTM (β-CrossLaps and PINP), BMD and microstructural and biomechanical parameters (micro-CT). Our results were: OP group has higher levels of β-CrossLaps and lower BMD at the femoral neck. Also, OP patients have a decreased volume of trabecular bone and less trabecular number, with architecture showing prevalence of rod-like trabeculae and worse connectivity than OA patients. The biomechanical parameters were worse in OP patients. BMD was correlated with almost all the structural and biomechanical parameters. Moreover, β-CrossLaps was negatively correlated with hip BMD and with bone surface density and positively with trabecular separation. BTM, BMD and bone microstructural changes in osteoporosis are opposite to those of OA. These findings justify a less resistant bone with higher risk of fragility fractures in OP patients. These histomorphometric and biomechanical changes may be suspected by measuring of BMD and β-CrossLaps levels.     

甲状腺透明变梁状肿瘤6例临床病理分析

目的：探讨甲状腺透明变梁状肿瘤( hyalinizing trabecudar tumor, HTT)临床病理学特征、鉴别诊断及治疗。方法回顾分析6例HTT的临床表现、超声检查、组织病理学及免疫表型特征,并复习相关文献。结果组织病理学显示瘤细胞呈梁状、器官样排列,小梁间见透明变性的基膜样物质沉积,细胞呈多角形或梭形;胞质嗜酸,细颗粒状,胞核圆形或卵圆形,常见核沟及核内假包涵体。免疫组化标记瘤细胞TG、TTF-1、CD56呈阳性,CK19散在(+),Galectin-3(-/+),不表达Calcitonin、MC、CEA、Syn、CgA,Ki-67表达膜阳性或质弱阳性,p53低表达。该肿瘤需与甲状腺乳头状癌、甲状腺髓样癌和副神经节瘤等相鉴别。结论 HTT是一种罕见的甲状腺肿瘤,多表现为良性的形态学及生物学行为,准确的病理学诊断对其临床治疗及预后有极其重要的作用。     

Massive acetabular bone loss: Limits of trabecular metal cages

Massive acetabular bone loss (more than 50% of the acetabular area) can result in insufficient native bone for stable fixation and long-term bone ingrowth of conventional porous cups. The development of trabecular metal cages with osteoconductive properties may allow a more biological and versatile approach that will help restore bone loss, thus reducing the frequency of implant failure in the short-to-medium term. We report a case of massive bone loss affecting the dome of the acetabulum and the ilium, which was treated with a trabecular metal cage and particulate allograft. Although the trabecular metal components had no intrinsic stability, they did enhance osseointegration and incorporation of a non-impacted particulate graft, thus preventing failure of the reconstruction. The minimum 50% contact area between the native bone and the cup required for osseointegration with the use of porous cups may not hold for new trabecular metal cups, thus reducing the need for antiprotrusio cages. The osteoconductive properties of trabecular metal enhanced allograft incorportation and iliac bone rebuilding without the need to fill the defect with multiple wedges nor protect the reconstruction with an antiprotrusio cage.     

Generation of an atlas of the proximal femur and its application to trabecular bone analysis

Automatic placement of anatomically corresponding volumes of interest and comparison of parameters against a standard of reference are essential components in studies of trabecular bone. Only recently, in vivo MR images of the proximal femur, an important fracture site, could be acquired with high‐spatial resolution. The purpose of this MRI trabecular bone study was two‐fold: (1) to generate an atlas of the proximal femur to automatically place anatomically corresponding volumes of interest in a population study and (2) to demonstrate how mean models of geodesic topological analysis parameters can be generated to be used as potential standard of reference. Ten females were used to generate the atlas and geodesic topological analysis models, and 10 females were used to demonstrate the atlas‐based trabecular bone analysis. All alignments were based on three‐dimensional (3D) multiresolution affine transformations followed by 3D multiresolution free‐form deformations. Mean distances less than 1 mm between aligned femora, and sharp edges in the atlas and in fused gray‐level images of registered femora indicated that the anatomical variability was well accommodated and explained by the free‐form deformations. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

青光眼激光治疗的新进展

近年来,激光用于青光眼的治疗随着激光技术和眼内窥镜技术的不断发展而有了新的进展。选择性激光小梁成形术（SLT）、内窥镜下睫状体光凝术（ECP）和激光小梁切开术（LTA）等以其安全、有效、并发症少等优点而受到关注。SLT选择性作用于色素性小梁细胞,无热损伤,其降眼压疗效显著而安全。ECP是在眼内窥镜引导下对睫状体进行光凝,手术定位准确、并发症少,对难治性青光眼有较好的降眼压效果。LTA是用激光将部分小梁组织切除,建立直接通向Schlemm管的通道,而无须损伤结膜,是一种很有希望的抗青光眼手术。就SLT、ECP和LTA的新进展进行综述。     

羊膜与SK GEL生物胶在兔非穿透性小梁切除术中的应用

目的探讨保存人羊膜组织、sKGEL生物胶（交键透明质酸钠凝胶）在兔非穿透性小梁切除术中抗瘢痕化的安全性及有效性。方法新西兰白兔18只，随机分为A、B、c3组，每组各6只，每组兔的单眼行非穿透性小梁切除术。A组术中植入羊膜，B组术中植入SKGEL生物胶，C组术中无植入物。观察各组滤过泡的形态、内部结构及维持时间。结果A、B组滤过泡的形态及维持时间均优于c组。病理切片显示滤过空腔的保持与植入物有关，术后12周时A、B组眼空腔仍维持较好．c组眼瘢痕形成明显。结论保存人羊膜、SKGEL生物胶在兔非穿透性小梁切除术中应用均可减轻手术区滤过腔瘢痕的形成，安全有效。[眼科新进展2007；27（2）：106—109]