正常与畸形愈合跟骨应力分布的比较研究

 目的 探讨在静力载荷作用下,正常与畸形愈合跟骨的应力分布差异。方法 将正常跟骨有限元模型的后关节面由内向外、由前向后楔形切除,模拟骨折后距下关节面塌陷的畸形愈合模型。切除前B?hler角为35°,切除后为0°。自足跟及跟腱附着点处分别垂直向上对模型施加320 N和160 N的载荷,观察畸形愈合跟骨的Vonmises应力分布,并与正常模型进行比较。结果 畸形愈合跟骨的距下关节面应力降低,应力分布特点为从正常的跟骨前中关节面为主要应力区转为跟骨外侧紧靠跟骰关节处,外侧主要应力区要高于内侧,是支撑载荷的主要部位。从跟骨结构的细化比较来看,首先,距下关节面顶部的塌陷造成跟骨主要应力区部分后移,转至跟腱附着点处由正常的(1.51±0.22) MPa增至(3.11±0.24) MPa,而距下关节面顶部的应力由正常的(6.71±0.37) MPa减至(2.83±0.49) MPa。其次,跟骨前侧近跟骰关节处应力明显加大,由正常的(0.46±0.15) MPa增至(2.13±0.15) MPa,载距突应力由5.18 MPa减少至1.41 MPa。结论 跟骨骨折距下关节面塌陷是多数病理变化的主因,在临床治疗中应先解决距下关节面的塌陷问题,恢复跟骨正常高度,跟骨内部应力的分布对解决跟骨骨折后期出现的相关部位疼痛至关重要。     

兔胫骨应力应力电位与骨折愈合相关性研究

将６０只兔之胫骨中上段人工骨折前后，和对骨折断端施加不同的轴向压力后用改良的Ｆｒｉｅｎ－ｄｅｎｂｅｒｇ方法测定骨折端的电变化，结果表明，半环槽式外固定器的穿放与滞，不影响骨表面的电位值。     

骨折愈合的基本概念

１简要历史十九世纪中叶，ＲＶｉｒｃｈｏｗ创立细胞病理学，至十九世纪七十年代，各种骨细胞的形态概念已经确立，但骨折愈合过程的系统描述始于二十世纪初〔１，２〕，稍后于伦琴（１８９５）发现Ｘ射线。尽管浩瀚的文献不断丰富对骨折愈合的认识，到二十世纪七十年代...     

压应力促进骨折愈合的实验观察

轴向加压有利于骨折愈合的概念已被广泛接受,特别是经皮穿针骨外固定加压具有对骨折端血供无明显干扰,术后可对加压量进行调整,及应力遮挡小等优点已得到了学术界的高度重视。但轴向加压量与骨愈合的相关性尚鲜有报道。本实验旨在半环槽式外固定器条件下,通过组织学结构观察和生物力学测试等手段,了解不同的加压量对骨愈合的影响规律,探讨其最佳相关性,为临床治疗提供参考依据。     

微动应力与骨折间接愈合

骨折断端存在相对移动时,骨折以间接愈合的方式连接。微动应力能促进骨折的愈合,但程度与应力的方向及强度有关。机械应力对成骨细胞的生物刺激效应是促进骨痂形成的重要因素之一。应力使骨内发生应变,增加胰岛素样生长因子的分泌,促进骨形成。不过,骨折愈合不同阶段所需应力的相关参数尚未确立,其确切的细胞学机制与分子生物学机制仍不清楚。     

循环应力促进骨折愈合的生物力学实验研究

目的：探讨循环应力对骨折愈合的生物力学影响。方法：应用循环应力刺激仪,对８６只新西兰大白兔进行促进桡骨骨折愈合的动物实验研究。设对侧桡骨对照组。定期取标本做三点弯曲应力、弯曲力矩、抗弯刚度及骨痂横截面积等生物力学测定。结果：１２ｄ后,两组间弯曲力矩有显著性差异（Ｐ＜００１）。１５ｄ后弯曲正应力、抗弯刚度及骨痂横截面积出现显著性差异（Ｐ＜００１）。特别是抗弯刚度,差别＞４７％。提示循环应力刺激可提高骨痂的材料特性与结构特性。结论：加强其抗弯曲能力与抗破断能力,能促进骨折的愈合。     

轴向应力促进胫骨骨折愈合的三维有限元力学参数优化研究

目的通过有限元方法建立胫骨骨折愈合仿真模型,利用有限元分析不同频率与大小组合的轴向应力促进骨折愈合过程,以期获得最佳理论参数。方法对一名健康志愿者胫骨进行CT扫描,通过Mimics、Geomagic、Abaqus等有限元软件建立胫骨骨折钢板内固定实体模型;观察胫骨骨折愈合过程中骨痂内部应力、应变及骨折端位移,比较骨折愈合仿真所获得的愈合模式图及骨痂单元数变化。结果通过有限元分析计算了胫骨骨折间隙内骨痂组织的应力、应变及位移,观察分析200 N、1 Hz组合参数分化的成熟骨组织细胞单元数是最多的。结论建立胫骨骨折愈合的三维有限元模型,通过三维有限元分析所获得的200 N、1 Hz为最佳理论参数组合,为临床个体化促进胫骨骨折愈合提供理论依据。     

骨折愈合相关因素的研究进展

骨折愈合是一个极其复杂的组织学和生物化学变化过程,其所需时间相对漫长,影响因素众多.骨折延迟愈合(delayed union)与骨不连(nonunion)的发生率为5％～10％,好发于四肢长管状骨骨干,常见有胫骨干中下1/3交界处骨折、股骨颈骨折、肱骨干骨折、腕舟骨骨折和距骨骨折,其中以胫骨干中下1/3交界处骨折、头下型股骨颈骨折骨不连最为多见[1-2].由于骨不连产生的疼痛、肢体功能和心理障碍,给患者带来了极大的痛苦和经济负担,严重影响患者的生活质量,所以骨折愈合影响因素的研究一直是骨科学研究的重点和热点.近年来国内外的研究取得了很大的进展,现就近年有关骨折愈合影响因素方面的研究做一综述.     

骨生长因子促进骨折愈合研究进展

骨生长因子促进骨折愈合的基础研究与临床应用,从体内骨生长因子促进骨折愈合与骨发生机制,到给予外源性重组人骨生长因子治疗骨折,再到外源性导入骨生长因子基因诱导其表达来促进骨折愈合研究,取得了长足的进步和令人满意的效果。该文就骨形态发生蛋白、成纤维细胞生长因子、血小板衍生生长因子、血管内皮细胞生长因子、转化生长因子及胰岛素样生长因子促进骨形成和骨重建的生物学作用、近年在骨折愈合方面的研究进展及存在的问题作一综述。     

应力促进下肢长骨干骨折愈合的探讨

自１９８３年以来，对４０例下肢长骨干骨折患者，其中股骨１２例，胫腓骨２８例，采用骨折部髓内钉固定，外用下肢绞链支具外固定，使患肢早期负重、持拐行走。利用对骨折部的合理压应力，以促进骨折愈合。经６个月～１１年，平均１．５年随访，其中５～７周内骨折愈合者占４０％，较传统方法缩短疗程１／３～１／２，无１例发生骨不连接和延迟愈合。股骨组和胫腓骨组愈合时间无明显差异。由于早期负重活动，也减少了因骨折后长期卧床制动带来的股四头肌粘连、膝关节僵硬等多种并发症。     

骨折愈合的应力适应性研究

目的 探讨骨折端受力、肌肉动力、骨痂密度与骨折愈合的关系。方法 通过传感器电测技术与X线灰度分析的方法，从三个方面对骨折愈合的应力适应性进行了研究：①分别对14只1岁龄山羊进行了断端受力与骨折愈合的关系的研究；②对10只健康成年家兔进行了肌肉动力与骨折愈合的关系的研究；③对56只健康成年家兔进行了骨痂密度与骨折愈合的关系的研究。结果与结论 ①理想的骨折愈合与最佳的应力状态相适应；②肌肉动力是应力适应的反馈调节因素；③骨痂密度是应力适应的反馈结果。     

影响骨折愈合的生物物理学因素研究进展

[目的]骨折愈合是一个复杂而连续的过程,其并发症之一是骨折延迟愈合或者不愈合。许多实验和临床研究证实,生物物理学因素可以影响骨折愈合。目前影响骨折愈合的生物物理学因素主要包括:脉冲电磁场,低强度脉冲超声,体外振动波,高压氧等。有效的生物物理学干预可促进骨折的愈合,减少骨折延迟愈合或者不愈合的发生率,本文就影响骨折愈合的生物物理学因素及其意义的研究进展做一综述。     

骨折愈合的应力适应性研究

设计了生物适应性很强的力学控制装置──滑动机械加载控制器,对骨折断端没有应力遮挡,把肌肉动力与肢体负重力作为执行力学加载的源动力,通过压力传感器、多导传感放大器动态记录生理活动状态下断端受力情况及愈合过程中断端的应力状态。结果表明,同一时期内骨折断端压力随肌肉收缩及步态发生变化,不同愈合时间断端压力均值随时间的增加而逐渐增加,而滑动机械加载控制器上承载由术后当日平均2.4kg逐渐变小至术后五周平均0.78kg.同时,通过解剖显微镜进行断端骨痂显微观察,显示断端完全由外骨痂包绕,从而认为骨折断端压力变化是肢体功能恢复,断端骨痂承受载荷的表现,提示临床骨折固定后应适时地进行功能锻炼,肌肉收缩、患肢负重可为断端提供最好的力学环境──生理应力状态。     

骨折愈合的应力适应性研究──功能活动时兔胫骨断端应力状态的动态观察

设计了生物适应性很强的力学控制装置──滑动机械加载控制器，对骨折断端没有应力遮挡，把肌肉动力与肢体负重力作为执行力学加载的源动力，通过压力传感器、多导传感放大器动态记录生理活动状态下断端受力情况及愈合过程中断端的应力状态。结果表明，同一时期内骨折断端压力随肌肉收缩及步态发生变化，不同愈合时间断端压力均值随时间的增加而逐渐增加，而滑动机械加载控制器上承载由术后当日平均２．４ｋｇ逐渐变小至术后五周平均０．７８ｋｇ。同时，通过解剖显微镜进行断端骨痂显微观察，显示断端完全由外骨痂包绕，从而认为骨折断端压力变化是肢体功能恢复，断端骨痂承受载荷的表现，提示临床骨折固定后应适时地进行功能锻炼，肌肉收缩、患肢负重可为断端提供最好的力学环境──生理应力状态。     

Angiogenesis is required for stress fracture healing in rats

Although angiogenesis and osteogenesis are critically linked, the importance of angiogenesis for stress fracture healing is unknown. In this study, mechanical loading was used to create a non-displaced stress fracture in the adult rat forelimb. Fumagillin, an anti-angiogenic agent, was used as the water soluble analogue TNP-470 (25 mg/kg) as well as incorporated into lipid-encapsulated α_vβ₃ integrin targeted nanoparticles (0.25 mg/kg). In the first experiment, TNP-470 was administered daily for 5 days following mechanical loading, and changes in gene expression, vascularity, and woven bone formation were quantified. Although no changes in vascularity were detected 3 days after loading, treatment-related downregulation of angiogenic (Pecam1) and osteogenic (Bsp, Osx) genes was observed at this early time point. On day 7, microCT imaging of loaded limbs revealed diminished woven bone formation in treated limbs compared to vehicle treated limbs. In the second experiment, α_vβ₃ integrin targeted fumagillin nanoparticles were administered as before, albeit with a 100-fold lower dose, and changes in vascularity and woven bone formation were determined. There were no treatment-related changes in vessel count or volume 3 days after loading, although fewer angiogenic (CD105 positive) blood vessels were present in treated limbs compared to vehicle treated limbs. This result manifested on day 7 as a reduction in total vascularity, as measured by histology (vessel count) and microCT (vessel volume). Similar to the first experiment, treated limbs had diminished woven bone formation on day 7 compared to vehicle treated limbs. These results indicate that angiogenesis is required for stress fracture healing, and may have implications for inducing rapid repair of stress fractures.     

Therapeutic ultrasound in fracture healing: The mechanism of osteoinduction

Background:

Ultrasound has been used therapeutically for accelerating fracture healing since many years. However, the controversy on the exact mechanism of osteoinduction still continues. In this study, we try to bring out the exact biomolecular mechanism by which ultrasound induces fracture healing.

Materials and Methods:

The study was conducted in two phases: animal experiments and clinical study. In the first phase, we induced fractures on the left tibia of Wistar strain rats under anaesthesia. They were divided into two groups. One of the groups was given low-intensity, pulsed ultrasound (30 MW/cm²) 20 min a day for 10 days. Tissue samples and radiographs were taken weekly for 3 weeks from both the groups. In the second phase of our study, ten patients with fractures of the distal end of the radius (ten fractures) were included. Five of these were treated as cases, and five were treated as controls. Ultrasound was given 30 MW/cm² for 20 min every day for 2 weeks. The patients were assessed radiologically and sonologically before and after ultrasound therapy. Tissue samples were studied with thymidine incorporation test with and without adding various neurotransmitter combinations.

Results:

Radiological findings revealed that there was an increased callus formation in the ultrasound group. At the cellular level, there was an increased thymidine incorporation in the ultrasound group. When various neurotransmitters were added to the cells, there was an increased thymidine incorporation in the ultrasound group.In the second phase of the study, radiological and sonological assessments showed that there was an increased callus formation in the ultrasound group. In cytological study, thymidine incorporation was found to be increased in the ultrasound group.

Conclusions:

The results of animal and clinical studies demonstrated an early and increased callus formation in the ultrasound group. Cytological studies revealed increased thymidine incorporation, suggesting increased osteoblastic activity.     

可控性应力与微动对骨折愈合影响的组织学研究

目的 探讨骨折端在不同轴向应力作用下,不同骨折愈合时期所需轴向应力的适宜力值. 方法 32只青山羊均行股骨干中段横行截骨制作骨折模型,按骨折端施加实验动物自身体质量的0倍(对照组)、1/6(A组)、1/3(B组)、1/2(C组)应力分为4组,每组8只.术后4、8周分批处死,每次每组处死4只,行大体观察和组织学观察,测量骨折端骨外膜骨痂面积. 结果 对照组有1只动物骨折端发生成角畸形,实验A、B、C组分别有1、2、4只动物骨折端发生成角畸形.术后4周,对照组、A、B、C组骨折端骨外膜骨痂面积平均值分别为(1.15±0.34)、(1.86±0.28)、(2.18±0.36)、(1.99±0.33)cm~2,A、B、C组分别与对照组比较,骨折端骨痂生成多,骨外膜骨痂面积差异有统计学意义(P<0.05).术后8周,沿轴向排列骨外膜骨痂中骨性骨痂多、致密,皮质骨松化明显;对照组、A、B、C组骨折端骨外膜骨痂面积平均值分别为(1.38±0.31)、(2.09±0.23)、(2.69±0.28)、(2.71±0.31)cm~2,A、B、C组分别与对照组比较,B、C组分别与A组比较,差异均有统计学意义(P<0.05). 结论 骨折端施加轴向应力时能促进骨折端骨痂生长,较大的应力强度能更好地促进骨折端骨痂生长,但同时会造成骨折愈合成角畸形发生率增高.骨折端施加自身体质量的1/3应力时骨折端成角畸形发生率较低,最适宜促进骨折端骨痂生长.     

高能震波促进骨折愈合机理的探讨

目的 探讨高能震波（ＨＥＳＷ）对兔骨折愈合的影响及其机理。方法 手术造成家兔双侧胫骨标准骨折模型,对１侧胫骨骨折部施以ＨＥＳＷ;另１侧为对照。术后每周进行Ｘ线及组织学检查,并取骨折骨痂切片用骨形态发生蛋白（ＢＭＰ）抗体进行免疫组织化学染色（ＳＡＢＣ法）。结果 Ｘ线摄片及组织学观察显示,实验侧骨痂出现时间及骨折愈合时间均明显早于对照组;骨痂区毛细血管计数、ＢＭＰ表达强度在第２～４周时实验侧均明显大于     

Effects of social stress and fluoxetine treatment on fracture healing in a rat femur fracture model

BackgroundMental stress and depressive disorders have negative effect on bone biology and increase fracture risk. Fluoxetine is a widely used selective serotonin reuptake inhibitor in the treatment of these disorders. We aimed to evaluate the effects of social stress and fluoxetine treatment on fracture healing.MethodsThis study was performed with 32 male Sprague–Dawley® rats. Rats were randomly divided into four groups with eight rats in each group. Social stress regimen was performed in groups 3 and 4 for 15 days. Placebo for groups 1 and 3 and fluoxetine for groups 2 and 4 was administrated. Rat femur open (osteotomy) fracture model was performed. Placebo and fluoxetine were continued to be given to the same groups for four weeks until sacrification of animals. Sacrificed right femurs of subjects were evaluated histologically and radiologically. The obtained data were statistically analyzed using the SPSS 23 (Statistical Package for the Social Sciences) program.ResultsFracture healing score that evaluates the fracture healing quantitatively based on histological scale and bone mineral density of group 3 were significantly lower than other groups, and there was no significant difference between other groups. Inflammation score of group 2 was significantly lower than group 3. Group 1 had higher new callus formation/original cortex volume than group 2 and group 3. In immunohistochemical evaluation, the H-score of BMP-7/osteoblast in group 3 was lower than in group 1. The H-score of CD34 in group 3 was lower than in group 1.DiscussionThe positive and negative effects of fluoxetine, which is used in the treatment of depressive disorders, on wound, tendon, or bone healing have been shown in the literature. In this study, we showed the negative effects of depression on the early stages of fracture healing. Although fluoxetine had no detrimental effect on fracture healing in non-depressive rats, impaired fracture healing was reversed and better radiological and histological findings were obtained in depressive rats treated with fluoxetine. Our findings indicate that fluoxetine, which minimizes the negative effects of social stress on bone healing, can be used safely in the treatment of depressive disorders in patients with fractures.