膝内翻引起胫骨平台内侧骨质增生的模拟

本研究首先采用非线性骨再造速率方程和有限元方法相结合，引入拓扑优化思想，从不确定外形出发，模拟了正常力学环境下的胫骨上端外部形状和内部结构。然后以得到的正常力学环境下的胫骨上端外部形状和内部结构为初始模型，根据骨质增生形成的过程，提出膝内翻时胫骨平台上所受压力的分布随内翻角度的变化以及骨质增生过程中平台上受力分布和骨刺上压力分布改变的假设。模拟了膝内翻引起胫骨平台内侧的骨质增生。在模拟的过程中，总结出了一种符合骨质增生生理过程的模拟方法。     

正常和膝外翻情况下胫骨近端内部结构模拟

目的模拟正常和膝外翻时胫骨近端的内部结构。方法采用定量骨重建理论与有限元法相结合,对正常力学环境下胫骨近端的内部结构进行模拟,然后以此结构为初始模型,根据膝外翻情况下胫骨平台压力分布的改变规律,合力的作用点在胫骨外侧平台上,模拟膝外翻后胫骨近端内部结构。结果模拟得到的骨密度分布与真实胫骨进行对比,无论是正常力学环境下还是膝外翻情况下,都与实际非常吻合。结论本研究所采用的方法与载荷的分布方式能够正确地模拟预测胫骨近端内部结构,是进一步研究全膝关节置换术后假体周围骨重建行为的基础。     

椎体结构生长过程模拟

本文的目的是利用骨自优化理论完成椎体的外形、内部结构及生长过程的模拟。采用了一种新的自优化方程与有限元相结合的方法,引入工程拓flwh｛：k思想,从不确定的外形出发进行模拟;实测了人椎体冠状面的外形及内部结构。预测的结果在外形和内部结构上与实测相～致。外形上老年比年轻时的椎体具有更向内凹的腰鼓型,小梁骨主要沿主应力即垂直方向排列,只不过,老年时更疏松。迄今为止,仅有以荷兰的Huiskes为代表的少数人研究了适应性骨重建过程模拟模型的特性。而他们对于所选取模型的研究,也仅仅是在某个特定的初始形状、初始均匀密…     

椎体结构及其生长过程模拟

目前,关于骨自优化,或称自适应的定量描述,只有线性的骨再造速率方程,用它与有限元相结合去预测骨结构,仅限于在实测骨的外部几何形状基础上,预测其内部组织结构.至于骨的外部几何形状的模拟预测未见报道.本文的目的是利用骨自优化理论完成椎体的外部几何形状、内部组织结构及生长过程的模拟.采用了一种新的高阶非线性骨再造速率方程与有限元相结合,引入工程拓扑优化思想,从不确定的外形出发进行模拟;并且实测了人第三腰椎椎体冠状面的外部几何形状及内部组织结构.预测的结果在外部几何形状和内部组织结构上与实测相一致.外形上老年期比年轻期椎体具有更向内凹的腰鼓形,小梁骨主要沿主应力即垂直方向排列,只不过,老年期更疏松.是否可以说,采用这种自优化方程与有限元相结合,引入拓扑优化思想,不但能模拟预测骨的外部几何形状和内部组织结构,而且可以模拟其生长过程.尤其值得强调的是实现了外部几何形状的模拟,只有这样才能得以实现生长过程的模拟预测.     

椎体结构及其生长过程模拟

目前,关于骨自优化,或称自适应的定量描述,只有线性的骨再造速率方程,用它与有限元相结合法预测骨结构,仅限于在实测骨的部几何形状基础上,预测其内部组织结构。至于骨的外部几何形状的模拟预测未见报道。本文的目的是利用骨自优化理论完成椎体的外部几何形状、内部组织结构及生长过程的模拟,采用了一种新的高阶非线性骨再造速度方程与有限元相结合,引入工程拓扑优化思想,从不确定的外形出发模拟;并且实测了人第三腰椎椎体冠状面的外部几何形状及内部组织结构。预测的结果在外部几何形状和内部组织结构上与实测相一致。外形上老年期比年轻期椎体具有更向内凹的腰鼓形,小梁骨主要沿主应力即垂直方向排列,只不过,老年期更疏松,是否可以说,采用这种自优化方程与有限元相结合,引入拓扑优化思想,不但能模拟预测骨的外部几何形状和内部组织结构,而且可以模拟其生长过程。尤其中调的是实现了外部几何形状的模拟,只有这样才能得以实现生长过程的模拟预测。     

基于骨骼自适应理论优化模型的骨重建数值模拟

我们根据骨重建的自适应理论以及结构优化方法,建立了骨重建数值模拟的反问题求解模型和算法.由材料密度分布描述骨内部重建,材料密度的变化通过优化方法求解.股骨、长骨干和腰椎体冠状面(外部形状和内部结构)重建模拟的计算结果,符合实际情况,反映了骨结构对荷载环境的自适应特征,表明本文方法是骨重建研究的一种有效数值方法.     

定制化胫骨平台系统的构建及应用

为解决传统人工胫骨平台假体个体匹配性差，结构强度与生物活性难统一等问题，提出了定制化复合增强型人工胫骨平台系统的设计制造方法。采用解剖学建模技术设计出外形匹配，内含三维网状构架的复合假体模型，利用快速成型技术制造出假体的树脂原型，并分别通过精密铸造和粉末烧结技术制造出钛合金胫骨平台和大段多孔陶瓷人工骨。结果显示，该方法能快速而精确地制造出形状复杂的人工胫骨平台系统，是实现假体定制化制造的有利保证；通过将金属假体和多孔陶瓷人工骨复合，解决了载重部位大段骨缺损的修复问题。临床应用表明，该假体能与对侧关节匹配运动，通过将机械重建与生物重建相结合可实现受损关节的功能重建。     

胫骨假体放置位置与人工膝关节置换后的稳定性

背景：目前关于在全膝置换中针对选择何种参照方法和技术来确定胫骨假体放置位置或参数尚报道较少。 目的：分析人工膝关节置换过程中胫骨假体放置的位置对其置换后稳定性及相容性的的影响。 方法：通过检索选择文章内容与人工膝关节置换过程中胫骨假体或角度相关的文章,同一领域文献则选择近期发表或发表在权威杂志文章。 结果和结论：初检得到132篇文献,根据纳入标准选择关于胫骨假体放置的27篇文章进行综合分析。由于胫骨上端几何结构的个体差异以及手术操作等原因,假体与胫骨上端切面有时不能良好匹配。全膝关节置换中,胫骨假体各面的角度、对线、对位对置换后膝关节的稳定性、屈伸功能和假体使用寿命均有重要影响;胫骨假体的放置直接关系到人工膝关节置换后假体的松动、下沉及术后关节感等。因此选用适合患者型号的假体,使假体与胫骨上端切面能良好匹配的同时,还要提高假体植入技巧,以增强假体的稳定性。     

腓肠内侧动脉穿支肌瓣治疗胫骨上端创伤性慢性骨髓炎

目的 总结腓肠内侧动脉穿支岛状肌瓣移植治疗胫骨上端创伤性慢性骨髓炎临床应用结果。方法 应用腓肠内侧动脉穿支岛状肌瓣移植治疗胫骨上端创伤性慢性骨髓炎12例（男8例，女4例）。年龄20～58岁（平均32岁）。供区均选用同侧小腿。肌瓣表面行一期中厚网状游离植皮，供区直接缝合。结果 1例术后发生表浅感染，经交换敷料逐渐愈合，肌瓣和其上植皮全部成活，术后经过顺利，术后随访半年～5．5年（平均2．5年），没有发现明显的供区功能障碍。取得了较满意的效果。结论 该肌瓣以腓肠内侧动脉穿支为血供，具有血供丰富，血管解剖恒定，血管蒂长，以及肌瓣较薄的优点，带蒂移植适宜修复胫骨上端慢性骨髓炎。     

胫骨近端解剖结构对髓内钉进针点的影响

目的 观测胫骨近端解剖结构,并探讨其对髓内钉进针点的影响.方法 分别在3具胫骨标本及其X线图片上测量髓内钉安全区解剖标志,研究其与髓内钉进针点之间的关系.在4具胫骨尸体标本上模拟胫骨髓内钉手术,观测模拟手术对胫骨的损伤.回顾性研究了5例应用胫骨髓内钉引起关节疼痛的患者.结果 最佳进针点在相对于胫骨结节内外侧(2.3±1.6)mm的位置.膝关节内最容易被损伤的解剖结构为:内外侧半月板的前角、胫骨平台的内外侧前缘和髌横韧带.结论 胫骨近端髓内钉的最佳进针点与胫骨近端的解剖结构、髓内钉的外形和手术入路相关.     

Computed tomography based evaluation of the bone mineral density around the fixation area during knee ligament reconstructions: Clinical relevance in the choice of fixation method

IntroductionThis study examined the bone density around the fixation area during knee ligament reconstructions and assessed how this clinical relevance can be applied to a firm construction for a reconstructed ligament.Materials and methodsFifty consecutive patients (25 healthy men and 25 healthy women) were enrolled in this study. A quantitative computed tomography was used to determine the trabecular bone density at the 7 clinically relevant areas (anteromedial area of proximal tibia, anterolateral area of proximal tibia, posteromedial area of the proximal tibia, posterocentral area of the proximal tibia, posterolateral area of the proximal tibia, near femoral tunnel entrance of the ACL, near the femoral funnel entrance of the PCL). The means and standard deviations of the areas of interest were measured using a 10 mm diameter circle and the bone density was compared.ResultsA comparison of the fixation areas in the proximal tibia, anteromedial area of proximal tibia showed the highest bone density and posterocentral area showed the lowest bone density. A comparison of the PCL tibial fixation with interference screws or trans-condylar fixation revealed the posterocentral area to have the lowest bone density. A comparison of the femoral fixation areas in the ACL and PCL reconstruction revealed no differences in bone density.ConclusionThe anteromedial area of the proximal tibia was most acceptable in the interference screw fixation and the posterocentral area had the lowest bone density in the proximal tibia. There were no differences in the femoral fixation areas in the ACL and PCL reconstruction.     

The effect of anterolateral ligament reconstruction on knee constraint: A computer model-based simulation study

BackgroundTo determine the influence of anterolateral ligament reconstruction (ALLR) on knee constraint through the analysis of knee abduction (valgus) moment when the knee is subjected to external translational (anterior) or rotational (internal) loads.MethodsA knee computer model simulated from a three-dimensional computed tomography scan of healthy male was implemented for this study. Three groups were designed: (1) intact knee, (2) combined Anterior Cruciate Ligament (ACL) and Antero-Lateral Complex (ALC) deficient knee, and (3) combined ACL and Antero- lateral Ligament (ALL) reconstructed knee. The reconstructed knee group was subdivided into four groups according to attachment of reconstructed anterolateral ligament to the femoral epicondyle. Each group of simulated knees was placed at 0°, 10°, 20°, 30°, 40° and 50° of knee flexion. For each position an external anterior (drawer) 90-N force or a five-newton meter internal rotation moment was applied to the tibia. The interaction effect between the group of knees and knee flexion angle (0–50°) on knee kinematics and knee abduction moment under external loads was tested.ResultsWhen reconstructed knees were subjected to a 90-N anterior force or a five-newton meter internal rotation moment there was significant reduction in anterior translation and internal rotation compared with deficient knees. Only the ALLR procedure using posterior and proximal femoral attachment sites for graft fixation combined with ACL reconstruction allowed similar mechanical behavior to that observed in the intact knee.ConclusionsCombined ACL and ALLR using a minimally invasive method in an anatomically reproducible manner prevents excessive anterior translation and internal rotation. Using postero-proximal femoral attachment tunnel for reconstruction of ALL does not produce overconstraint of the lateral tibiofemoral compartment.     

有限内固定联合外固定支架治疗高能量胫骨Pilon骨折

目的介绍有限内固定联合外固定支架治疗高能量胫骨Pilon骨折的经验和对其疗效进行评估。方法自2000年10月～2008年3月31例患者接受该方法治疗。该手术采用踝前内侧和外侧切口,暴露胫骨远端关节面和外侧腓骨,以螺钉或克氏针固定胫骨,重建钢板或克氏针固定腓骨,外固定支架的近侧螺钉置于胫骨骨折近端,远侧螺钉置于跟骨和距骨颈上。对31例高能量胫骨Pilon骨折进行随访,按Ruedi分型：Ⅰ型6例,Ⅱ型11例,Ⅲ型14例。结果采用Teeny等评分系统评估手术疗效,优17例（54．8％）,良10例（32．2％）,中2例（6．5％）,差2例（6．5％）。结论有限内固定结合外固定支架治疗高能量胫骨Pilon骨折显著减少伤口并发症及骨不愈合、延迟愈合,能较好地恢复踝关节功能,该术式可作为治疗高能量胫骨Pilon骨折的首选方法。但仍有螺丝钉松动,钉道感染等并发症。     

膝关节单髁置换胫骨优化截骨设计的生物力学研究

目的 比较膝关节单髁置换术(unicompartmental knee arthroplasty, UKA)常规截骨、保留圆角截骨及全新扩大圆角截骨方法对术后胫骨近端生物力学特性的影响。方法 基于Sawbones胫骨的CT数据,构建完整胫骨模型及不同截骨方式下UKA术后胫骨模型,采用轴向压缩工况对模型进行有限元分析,比较不同模型间胫骨近端应变情况及骨水泥应力差异。结果 在轴向压缩工况下,扩大圆角组其截骨区皮质骨von Mises应变峰值较常规截骨组与保留圆角组有所增加,而松质骨von Mises应变峰值则分别减少24.3%～42.9%、26.0%～48.7%。对比截骨区松质骨与皮质骨von Mises应变峰值差Δε_peak,发现扩大圆角组其Δε_peak远远小于其余两组。UKA后不同模型间胫骨前内侧皮质骨最小主应变无明显差异,但较完整胫骨模型增加23.3%～34.5%。扩大圆角组骨水泥单元平均von Mises应力随着圆角半径增大呈现下降趋势,且整体均小于常规截骨组与保留圆角组。结论 全新扩大圆角截骨方法可使健康骨质条件下胫骨近端应力传递更均匀...     

Transepicondylar axes for femoral component rotation might produce flexion asymmetry during total knee arthroplasty in knees with proximal tibia vara

BackgroundAdequate rotation of the femoral component in total knee arthroplasty is mandatory for prevention of numerous adverse sequelae. Therefore, we investigate whether there is the distal femoral deformity in knees with tibia vara. The purpose of this study was to evaluate the reliability of the transepicondylar axis as a rotational landmark in knees with tibia vara.MethodsWe retrospectively reviewed and selected 101 osteoarthritic knees with proximal tibia vara and 150 osteoarthritic knees without tibia vara for inclusion in this study. The transepicondylar axis (TEA), anteroposterior (AP) axis and posterior condylar (PC) line were measured using the axial image from magnetic resonance imaging axial images. We compared the external rotation angle of the TEA relative to the PC line between groups in order to investigate the presence of distal femoral anatomical adaptation in the tibia vara group.ResultsThe TEA in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 6.0º of external rotation in the non-tibia vara group. The line perpendicular to the AP axis in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 5.4º of external rotation in the non-tibia vara group. Distal femoral geometry was unaffected by the tibia vara deformity.ConclusionsThe use of transepicondylar axes in determining femoral rotation may produce flexion asymmetry in knees with tibia vara.Level of evidenceLevel III     

弯曲应力作用下兔胫骨骨干皮质骨的骨重建方式

背景：骨所承受的应力变化是骨重建的重要刺激源。目前应力与骨重建关系的研究集中在轴向应力对骨重建的影响,而对弯曲应力环境下的骨重建模式缺乏研究。 目的：观察在长期弯曲应力作用下生长期兔胫骨骨干皮质骨骨重建的方式。 方法：在兔左胫骨近端内侧骨骺线远侧0.5 cm处开一直径2.5 mm骨窗,用冰盐水将兔胫骨及记忆合金片降温,降温后将记忆合金片拉直后经骨窗置入胫骨髓腔。记忆合金置入方向：使其复温后两端抵在外侧骨皮质上,弧形顶点抵向内侧骨皮质,缝合伤口。通过胫骨髓腔内置入的形状记忆合金片,给予兔胫骨骨干内部施加持续弯曲应力,观察胫骨骨干皮质骨在长期弯曲应力环境下骨重建的模式。 结果与结论：在6个月持续弯曲应力作用下,兔胫骨骨干张应力侧骨皮质变薄,压应力侧骨皮质增厚,胫骨未观察到明显弯曲形变,压力侧骨皮质增厚程度与胫骨上的应力分布有关。结构完整的胫骨对弯曲应力表现出一种内在的“抗性”,说明无骨折长骨骨干部分基本上不具备力线矫正潜力。实验结果提示,弯曲应力下兔胫骨骨干皮质骨骨重建模型创伤小,应力可控,不影响骨的生长和代谢,不限制实验动物活动,更符合生理状态,是一个理想的骨重建动物模型。     

Determination of sex from the tibia of adult Turkish cadavers

The aim of this research is to determine sex from the tibia. The tibia is an ideal bone because it resists erosive forces and keeps its anatomical shape for a long time even after being buried. Additionally, we tried to obtain a higher discrimination rate by using the biarticular breadth that was accepted as the most valid criterion in previous sex discrimination studies which were directed to the proximal part of the tibia. Right and left tibiae from 55 randomly selected adult Turkish cadavers (25 to 68 years) were measured to the nearest millimeter performed with a caliper; a total of six dimensions, one from the proximal and five from the distal ends, was measured. Canonical discriminant function test was performed to develop formulae and assess the accuracy of the technique. The results indicated that classification accuracy ranged from 89% in the right and 87% in the left for biarticular breadth. There was a minimal difference between the sides and the height of the medial malleolus. In conclusion, the distal and proximal dimensions of the tibia are highly discriminative as the sexual dimorphs in this Turkish sample. The study compares well with those on blacks and whites of North America and South Africa.     

Anterior tibial artery and its actual projection on the lateral aspect of the tibia: a cadaveric study

The anterior tibial artery (ATA) is at risk of injury during high tibial osteotomy, Ilizarov wire placement, pin placement in external fixation, or proximal locking screw insertion, as the artery is not visualized intraoperatively. The ATA is anchored to the oval foramen of the interosseous membrane on the proximal tibia by the deep fascia and recurrent genicular vascular branches. Segment 1 (from the bifurcation of the popliteal artery to the level of the interosseous foramen) and the proximal part of segment 2 (from the interosseous foramen to the level where the artery crosses the anterior border of the tibia) may be damaged when pin, wire or screw placement is directed posterolaterally at that level. Distally, a straight mediolateral pin or Ilizarov wires may lacerate the artery. Segment 2 of the ATA descends against the interosseous membrane in its proximal part, which is projected on the posterior third of the tibia relative to the sagittal plane; in its middle part, it runs close to the lateral cortex of the tibia, it is projected on the middle third of the tibia; in its distal part it runs gradually towards the anterior third of the tibia and contacts with the anterior third of the tibial cortical surface. This information may help reduce risk of injury to the ATA during high tibial osteotomy, external fixation and pin placement or insertion of locking screws.