恒力法测量制动对兔髌韧带截面面积的影响

本文介绍了一种测量软组织截面面积的装置和方法。通过对兔髌韧带的反复测量,结果显示其变异系数在0．9％以下。用此测微仪对膝关节制动前后兔髌韧带截面面积的测量发现：制动6周后髌韧带的截面面积明显增大。作者认为这种变化与组织的胶原代谢水平相关。     

髓内针置入内固定胫骨骨折后膝关节功能比较及组织学评价

背景：髓内钉内固定后膝关节组织生物学改变也是影响膝关节功能的重要因素。 目的：分析比较胫骨骨折经不同入路髓内针固定后膝关节功能,并对入口周围髌韧带和脂肪垫损伤进行组织学比较评价。 方法：纳入分析45例闭合性胫骨干骨折经髓内针治疗的患者资料,按照不同的置入途径分为3组：经髌韧带途径组、经髌韧带内侧旁组和髌韧带外侧旁组。 结果与结论：置入后膝关节功能评分各组间比较,差异无显著性意义(P > 0.05)。经髌韧带途径组置入过程中髌韧带和脂肪垫明显挫裂伤发生率高于其他两组(P < 0.05);置入后入路切口内瘢痕增生程度、膝关节功能障碍及疼痛程度经髌韧带组较髌韧带内侧旁组和外侧旁组要明显。说明和经髌韧带途径相比,髌韧带内侧旁和髌韧带外侧旁途径有着更好的膝关节功能和更轻的髌韧带和脂肪垫损伤。     

非周期大强度运动训练和推拿对兔膝关节髌韧带生物力学特性的影响

目的 观察非周期大强度运动训练和推拿对兔膝关节髌韧带生物力学特性的影响。方法 利用非周期大强度运动的动物训练模型造成关节韧带松驰，在训练的同时予以推拿手法恢复。结果 髌韧带生物力学测试发现运动训练可以明显引起韧带应力松驰加快，应力一应变关系右移，弹性系数降低，应变加大；而训练同时予以推拿恢复手段可明显恢复韧带的松驰。结论 非周期大强度运动训练可造成韧带松驰，推拿恢复手段可明显防止韧带的松驰。     

前交叉韧带粘弹性特性的实验研究

目的 探讨前交叉韧带的力学性能和粘弹性行为与时间的变化规律，为研究人工韧带提供生物力学参数。方法 对正常国人新鲜尸体膝关节前交叉韧带进行系统的拉伸、应力松驰、蠕变实验，得出最大载荷、强度极限、最大应变、弹性模量等；还得出了应力松驰、蠕变实验数据和曲线，归一化应力松驰函数、蠕变函数数据和曲线。并得到7200s时的蠕变量和应力松驰量。结果 ①前交叉韧带在实验中表现出典型的松弛、蠕变现象，说明其粘弹性性质在膝关节运动中起着重要的缓冲作用。②最初600s时应力应变的变化幅度较大，之后应力缓慢下降，应变缓慢上升，前交叉韧带7200s时应力松弛量1．05Mp，蠕变量为6．82％。结论 前交叉韧带具有良好的粘弹性力学性质。其粘弹性力学行为是为了适应其所在解剖部位的功能需要。     

内侧副韧带不同程度损伤时膝关节的应力变化

背景：膝关节内侧副韧带损伤易导致继发性的半月板及软骨损伤,长期慢性损害会引起骨关节炎的发生。目前,关于内侧副韧带断裂所致半月板及关节软骨损伤的力学研究较少。目的：探讨膝关节内侧副韧带不同程度损伤对膝关节半月板及软骨生物力学的影响。方法：选择一名健康志愿者行膝关节CT和MRI检查,获取其影像资料,将扫描数据依次导入Mimics、Geomagic及Solidworks软件,经配准融合后建立正常膝关节三维模型,并在此基础上模拟出膝关节内侧副韧带不同程度损伤的模型,共分为4组,包括：(1)内侧副韧带完整;(2)内侧副韧带深层断裂;(3)内侧副韧带浅层断裂;(4)内侧副韧带完全断裂。最后导入Ansys软件,对膝关节施加3种模式载荷：(1)股骨顶端施加10 N·m外翻力矩;(2)股骨顶端施加4 N·m内旋力矩;(3)股骨顶端施加4 N·m外旋力矩。分析4组模型在不同载荷下对膝关节生物力学的影响。结果与结论：(1)在膝关节伸直位,对膝关节施加10 N·m外翻力矩时,内侧副韧带不同程度损伤后外侧半月板总体应力均增加,关节软骨应力变化不明显,并且当内侧副韧带浅层出现断裂后外侧半月板应力峰值明显增大;(2...     

膝关节韧带的生物力学研究进展

膝关节韧带的生物力学是近年来研究的热点之一,力学刺激对调控韧带功能、韧带组织愈合和重建有着重要的作用,作者从膝关节韧带的结构、力学与生化特点、愈合与重建、施加应力与制动对韧带的影响、应力对韧带细胞分化的影响和前交叉韧带与内侧副韧带的对比研究等方面综述了近年来的一些研究进展。     

前交叉韧带及其替代物粘弹性性质的实验研究

本研究采用新鲜成人膝关节标本，对前交叉韧带及其转换替代物（髌韧带、髂胫束）进行系统的粘弹性力学性质的实验研究，通过粘弹性力学模型的建立，推导前交叉韧带及髌韧带、髂胫束的本构方程，对韧带的蠕变和松驰现象进行系统的分析。结果表明，韧带的损伤与韧带的生理力学性质有关，髌韧带的粘弹性性质更接近前交叉韧带，关节内髌韧带转换比髂胫束为佳。     

人体全膝关节精细有限元模型建立及有效性验证

近年来利用数字三维模型对人体全膝关节进行生物力学分析在国内外迅速发展,但是缺乏完整精细的膝关节有限元模型;同时对所建立模型的验证也比较单一,仅从韧带或者软骨受力单方面进行有效性的验证,导致模型的实用性和广泛性受到限制。目的以一种创新、高效的方法三维重建精细人体膝关节有限元模型,包括股骨、胫骨、髌骨、腓骨、股骨软骨、胫骨软骨、髌骨软骨、腓骨软骨、半月板、交叉韧带、侧韧带、髌韧带等组织结构,并对整体模型有效验证。方法利用CT和MRI医学影像,使用Mimics、3-Matic、Geomagic、Solidworks、Abaqus软件获得完整、精细的人体膝关节模型;在内外髁中点施加1 000 N竖直向下载荷,分析膝关节内外间室的力学分布及软骨的力学响应;以胫骨平台髁间隆起为参考施加134 N前向推力,模拟临床中的抽屉实验(ADT),获取各韧带组织的生物力学响应,并与现有人体实验及模型对比。结果 1 000 N载荷下,股骨软骨最大Mises应力值为2.514 MPa,半月板最大Miese应力值为7.693 MPa,胫骨软骨最大Mises应力值为1.848 MPa,均分布于膝关节的内侧;内外侧软骨接触面积分别为476.080 8 mm~2和338.446 8 mm~2;内外腔室分别承担总载荷的60.57%和39.43%。134 N载荷下,胫骨平台前端的位移量为5.687 mm;前十字交叉韧带(ACL)最大Mises应力值为28.030 MPa,后十字交叉韧带(PCL)最大Mises应力值为16.730 MPa,内侧副韧带(MCL)最大Mises应力值为4.511 MPa,外科韧带(LCL)最大Mises应力值为3.751 MPa;交叉韧带与股骨止点的最大Mises应力值为15.270 MPa。结论建立的精细膝关节三维模型很好地重塑了人体膝关节相关生物力学特性;该精细膝关节模型仿真结果与现有实验数据非常接近,证明了模型的有效性;完整、有效的精细全膝关节有限元模型将为植入物手术、人体运动分析、康复研究等打下基础。     

不同股骨止点对内侧髌股韧带重建后髌股关节应力影响的三维有限元分析

背景：髌股韧带重建有多种手术方式,其中股骨止点选取对手术实施影响较大,目前针对股骨止点的选取有多种方式,但无定论。目的：通过三维有限元软件分析膝关节不同屈曲状态下内侧髌股韧带（MPFL）股骨重建止点位置改变对髌股关节应力的影响,从而选择出合理准确的股骨重建止点。方法：获取成年人正常膝关节CT数据,导入Mimics、Geomagic及Soildworks软件进行提取模具、添加韧带,其中韧带的股骨止点选择分别为股骨内上髁与内收肌结节连线的中点、股骨内上髁、内收肌结节、股骨髁间窝顶部向内髁投射点和内收肌结节下10 mm,再将添加韧带后的模具导入机械软件Ansys,对不同股骨止点重建后髌股关节应力进行生物力学的有限元分析。结果与结论：（1）在膝关节屈曲0°和30°时,选取任一股骨止点产生的髌股关节应力大于其他屈曲角度（60°,90°,120°）;无论采取哪种位点作为股骨端止点,当膝关节屈曲超过30°时,髌股关节间的接触应力大小基本无差别;（2）在膝关节屈曲0°和30°时,以内收肌结节为止点的髌股接触压力最大,以股骨内上髁与内收肌结节连线的中点为止点的接触力最小;在膝关节屈曲30°时,股骨内上髁...     

骨性关节炎对膝关节软骨力学性质影响的实验研究

目的 研究正常国人新鲜尸体膝关节软骨和骨性关节炎膝关节软骨的生物力学性质,为临床提供生物力学参数。方法 取正常和病变的膝关节软骨在ShimadzuAUTOGRAPH电子万能试验机上进行一维拉伸实验。结果 得出了关节软骨最大载荷、伸长比、应力、应变等数据;用最小二乘法处理应力鄄应变数据,得出了其应力鄄应变关系表达式,拟合出了应力鄄应变曲线。结论 病变组各项力学性质指标均明显低于正常组。     

膝关节固定后髌骨腱的生物力学改变

背景：骨关节固定常作为防止受伤组织被再次损伤的方法。 目的：膝关节固定对兔髌骨腱力学特性及超微形态的影响。 方法：将20只成年兔等分为固定组和对照组。固定组兔左后肢通过石膏和2个可调铝夹板,保持膝伸直,踝关节屈曲90°,固定6周后,取髌骨腱-骨复合物,观察两组髌骨腱的生物力学性能和超微结构变化。 结果与结论：膝关节固定6周拉伸强度和切线模量分别下降至对照组的64.44%和53.08%(P < 0.01),但两组伸长率和最大负荷差异没有显著性意义。两组材料常数及应力应变关系曲线完全不同。固定组髌骨腱的横截面积明显大于对照组(P < 0.01),小胶原纤维占有优势。说明固定不仅会导致髌骨腱生物力学的变化,而且对髌骨腱自身也产生影响。     

Collagen cross-linking alterations in joint contractures: changes in the reducible cross-links in periarticular connective tissue collagen after nine weeks of immobilization.

A significant increase in the NaBH4 reducible intermolecular cross-links in the 9 week immobilized rabbit periarticular connective tissue was found. Dihydroxylysinonorleucine, hydroxylysinonorleucine, and histidinohydroxymerodesmosine were the major cross-links which increased during the period of immobilization. No change in the hydroxlysine/lysine ratio between the immobilized and control periarticular connective tissue collagen was detected during the 9 weeks of enforced immobilization of the rabbit knee. Since the collagen mass in the immobilized periarticular connective tissue does not change, or at most is reduced 10%, we suggest that there is an increase in collagen cross-links expressed both in per unit weight of collagen and on the basis of collagen mass per knee due to the lack of physical stress and motion.     

前交叉韧带力学特性差异对膝关节有限元仿真结果的影响

目的研究不同前交叉韧带力学特性对膝关节有限元模拟结果产生的影响。方法基于医学图像数据重建包含主要解剖结构在内的膝关节三维有限元模型,并考虑韧带的横观各向同性特性;用同一种韧带本构方程对3种不同前交叉韧带应力应变力学实验曲线进行参数拟合,对比不同的前交叉韧带力学参数对膝关节运动学和生物力学性能的影响。结果不同的前交叉韧带力学特性会得到不同的膝关节位移结果,前交叉韧带内的应力及应变大小有很大变化,但分布的趋势基本相同。结论选取不同前交叉韧带力学特性曲线会影响膝关节有限元分析的仿真结果,今后在关节组织力学性能的设置、模型的构建及验证中要足够重视。     

Arthroscopic Partial Meniscectomy versus Physical Therapy for Degenerative Meniscal Tear: a Systematic Review

BackgroundMeniscal tears are commonly observed in patients with knee osteoarthritis (OA), however, clinical significance of such lesions detected by magnetic resonance imaging is in many cases unclear. This study aimed to determine the clinical effectiveness of arthroscopic partial meniscectomy (APM) compared with non-operative care in patients with knee OA.MethodWe used existing systematic reviews with updates of latest studies. Three randomized controlled studies were selected, where two studies compared the effects of APM plus physical therapy (PT) with PT alone and one compared APM alone and PT alone. While 1 study exclusively included OA patients, 2 studies included 21.1 and 12% of patients with no radiographic OA. Patients with knee locking were unanimously excluded.ResultsUpon comparison of APM plus PT and PT alone, there was no significant difference observed in knee function, physical activity, or adverse events. Knee pain was observed to be significantly lower in the APM plus PT group at 6 months, but there was no difference between the two groups at 12 and 24 months. With respect to the comparison between APM alone and PT alone, PT was non-inferior based on the criteria for knee function during 24 months; however, knee pain was significantly reduced in the APM alone group.ConclusionsOur study showed that knee pain was significantly improved in the APM group compared to non-operative care group at 6 months and over 24 months. Our result was based on only 3 randomized controlled trials (RCTs) revealing a significant knowledge gap, hence demanding more high-quality RCTs in OA patients.Trial RegistrationPROSPERO Identifier: CRD42020215965     

Time-dependent properties of human umbilical fascia

This investigation is devoted to the study of the viscoelastic behavior of human abdominal fascia from the umbilical region. Seventeen samples 10 mm wide and up to 70 mm long were cut along the primary fiber direction (group FL) or perpendicular to it (group FT) and subjected to relaxation tests. The viscoelastic response of the tissue at three different strain levels (4%, 5%, and 6%) was investigated. The relaxation curves were fitted using a two-stage decaying exponential form. The following parameters were determined: initial stress σ(0), relaxation times τ(1) and τ(2), stress reduction Δσ, initial relaxation modulus E and equilibrium relaxation modulus E(eq), as well as the ratio E/E(eq). Fiber orientation and strain levels were varied to determine their influence on the viscoelastic properties of fascia. The results highlight the inherent viscoelastic mechanical properties of umbilical fascia. The values of the viscoelastic parameters determined for the longitudinal and transverse directions varied markedly. Significant differences were found between the two groups FL and FT for the initial stress at 5% and 6% strain (p < 0.038) and for the initial and equilibrium moduli at the 6% strain level (p < 0.046). The stress reduction in samples from the FL group (45-55%) was less than that in samples from the FT group (37-54%), but this difference was not significant (p > 0.388). The influence of strain level on the parameter values was not statistically significant (p > 0.121). The nonlinear response of the tissue was demonstrated over the chosen strain range.     

兔眼角膜生物力学特性的年龄相关性

目的 利用兔眼角膜条的单轴拉伸实验数据,研究角膜生物力学特性与年龄的相关性。 方法 分别取3月龄和7~8月龄兔眼角膜条,实施单轴拉伸实验,获得实验数据;用指数模型和幂模型对应力 应变数据进行分析;用黏弹性力学模型对应力松弛数据进行分析。结果 兔眼角膜条呈现非线性黏弹性特征。在实验误差允许的范围内,不同月龄兔眼角膜条的非线性应力-应变关系差别不明显,7~8月龄兔眼角膜的切线模量略偏大,但其应力衰减得明显快。不同的拉伸速率对3月龄兔眼角膜条非线性应力-应变关系的影响不明显,但快速拉伸后的角膜条应力衰减明显变快。结论 兔眼角膜随月龄增加会轻微变硬,而角膜的松弛特性随月龄变化明显。     

颈椎旋转手法对兔粥样斑块期颈动脉拉伸力学性能的影响

目的探讨颈椎旋转手法对兔粥样斑块期颈动脉拉伸力学性能的影响。方法选取30只健康的雄性新西兰大耳兔,随机分为实验组、模型对照组和空白对照组。实验组对兔进行颈动脉粥样硬化斑块造模及颈椎旋转手法干预,模型对照组仅进行颈动脉粥样硬化斑块造模,而空白对照组不进行任何干预。观测3组兔在不同干预后颈动脉各项拉伸力学性能指标的差异。结果实验组与模型对照组以及空白对照组比较,最大应变、最大载荷和生理性弹性模量均有统计学差异(P0.05);实验组最大应变比模型对照组、空白对照组分别小24.87%、52.09%;实验组最大载荷分别是模型对照组、空白对照组的2.21、3.47倍;实验组生理性弹性模量分别是模型对照组、空白对照组的1.60、1.89倍。结论相对正常颈动脉而言,颈动脉粥样硬化斑块的存在会降低颈动脉的拉伸力学性能,而对存在颈动脉粥样硬化的兔进行颈椎旋转手法操作,会进一步降低颈动脉的拉伸力学性能。因此,临床上对于存在颈动脉粥样硬化斑块的患者,最好避免进行颈椎旋转手法操作。     

Comparison of the effect of autologous and homologous injections of vitreous body with Hyalgan into the knee joint of the rabbit as an animal model

The histopathological properties of vitreous body have not yet been well clarified. This study compares the histopathological effects of autologous and homologous injections of vitreous body with Hyalgan into the knee joint of a rabbit. Thirty-six white New Zealand rabbits were divided into three equal groups. Under anesthesia and sterile conditions, rabbit vitreous body was obtained through the clear corneal incision with a trephine after lens delivery. In the first group, 0.5?ml of vitreous body was autologously injected into the rabbit's knee. In the second group, homologous vitreous body from one rabbit was injected into the left knee of another rabbit. In the third group, 0.5?ml of sodium hyaluronate (Hyalgan) was similarly injected into the rabbit's knee. Twelve rabbits were considered as control group and received just normal saline. Each group was subdivided into two groups, A and B. The rabbits' articular cartilages and synovial membranes were histologically investigated for any inflammation after 1?week for group A and after 12?weeks for group B. After 1?week, no significant difference was found between the autologous and homologous vitreous body and Hyalgan injection groups. In comparison with the control group, no significant histological differences were noted. After 3?months, in both homologous and autologous vitreous-treated groups, no signs of chronic inflammation were noticed. However, in the Hyalgan group, there were signs of mild synovial hyperplasia, moderate infiltration of lymphocytes, and mild increased vascularity without any signs of fibrosis. It seems that vitreous body can be a safe and proper substitute for Hyalgan to be injected into the joint space.