异体骨和异体骨骨水泥在骨骼重建方面的临床观察

目的研究异体骨和异体骨骨水泥重建骨缺损的疗效。方法本组42例，行异体骨植入的20例，异体骨骨水泥(异体骨粒与骨水泥体积比为1：1混合)重建的22例。结果42例患者随访3个月～2．5年，平均1．3a。其中20例用异体骨全部愈合，愈合时间3．5～7个月，平均5．2个月。22例异体骨水泥中有2例骨不连，其余均愈合，愈合率为90．9％，愈合时间为9～12个月，平均10．5个月。结论异体骨和异体骨骨水泥在骨缺损的重建上疗效优良，异体骨应用范围更广，治愈率更高，异体骨骨水泥在治疗良、恶交界性和恶性肿瘤上性能优越，尤其适应于生存时间长的骨肿瘤的保肢术是一种切实可行的方法。     

雌激素对骨重建过程的影响

骨重建 (Ｒｅｍｏｄｅｌｉｎｇ)是一个复杂而有序的代谢过程。骨的重建活动通常发生在骨的 4个表面即 4个包被 (皮质骨内、外表面 ,哈氏系统表面及小梁骨表面 )。雌激素对骨重建的过程有直接和间接的调节作用。雌激素缺乏会导致骨重建过程中骨表面骨吸收和形成发生一系列特征性的改变 ,其最终结果导致骨质疏松的形态学改变。一、历史回顾骨重建是骨生理学的一个重要方面。骨成熟期后 ,其生长与构型活动几乎消失 ,但骨重建或骨转换将持续终生。对骨重建的认识 ,历史上经历了曲折的过程[1 ] 。ＰａｒｆｉｔｔＡＭ认为[2 ] ,骨重建是成熟的骨组…     

煅烧骨成骨效应实验研究

作者采用取材丰富的家猪骨，经脱脂、脱蛋白、煅烧等工艺处理制成的煅烧骨（ＴｒｕｅｂｏｎｅＣｅｒａｍｉｃＴＢＣ）为植骨实验材料。将ＴＢＣ植入兔背肌肌囊、胫骨洞型骨膜骨缺损、桡骨骨干的骨膜骨缺损（２．５ｃｍ）内。术后２～１６周组织学观察表明：ＴＢＣ不引起组织排斥反应和炎症反应。ＴＢＣ网状孔隙内成骨活跃。荧光标记发现新生骨出现早、增加快、数量多。１６周ＴＢＣ与桡骨二断端愈合者１６／３０。     

血管内皮生长因子对骨重建的影响

骨重建是一个有多种细胞及各种生长因子共同参与的复杂过程.新生血管形成在骨修复中起着重要作用.近年来的研究证明,内源性血管内皮生长因子(VEGF)在软骨内成骨和膜内成骨中均可促进血管生成和骨形成.外源性VEGF在骨折、外伤等造成的骨缺损治疗中可增加血管数量、促进局部血供.外源性VEGF联合基因治疗是近年研究的重点,单独应用或与各种材料联合应用已取得满意效果,但目前仅限于动物模型研究,其安全性、技术问题有待解决.     

骨重建中的骨代谢指标

骨重建是破骨细胞和成骨细胞共同完成的旧骨退化,等量新骨取代的骨组织更新过程,在骨重建过程中,许多激素和细胞、体液因子以及细胞代谢产物影响骨的重建.目前国内外通过生物化学检测技术获得的骨代谢指标分为骨代谢调节激素、细胞与体液因子、骨吸收、骨形成标志物.笔者将影响骨重建生物化学指标的生理作用、临床意义进行综述.骨代谢指标虽不能作为骨质疏松诊断的金标准,但已广泛应用于临床,评价骨代谢状态、骨质疏松诊断分型、预测骨折风险、观察药物治疗的疗效,以及代谢性骨病的鉴别诊断.并且在抗骨质疏松药物的研究及流行病学研究方面具有重要应用价值.     

99Tc- MDP对骨重建的影响

双膦酸盐主要用于治疗以破骨细胞活性增加为病理特征的代谢性骨病,包括Paget's骨病(派杰氏病),肿瘤骨转移,恶性肿瘤引起的高钙血症和骨质疏松。从P-O-P结构的焦磷酸盐到P-C-P结构的第三代双膦酸盐,其抗骨吸收的作用随碳链接侧链的延长而增强。锝[99Tc]亚甲基二膦酸盐(99Tc-MDP)是双膦酸盐的一种,其主要成分是锝[99Tc]经氯化亚锡还原后与亚甲基二膦酸盐形成的螯合物,具有稳定的P-C-P键,被骨生成区和带有炎症的骨与软骨组织摄取,不仅有效降低血中免疫调节因子、抑制病理复合物产生;而且多项国内外研究发现,99Tc-MDP免疫调节同时具有抑制破骨细胞活性及修复破骨的作用,引起骨质疏松研究者的关注。本文综述了99Tc-MDP对骨重建影响的研究进展。     

氧化应激对骨重建的影响

骨形成和骨吸收之间的协调平衡共同维持着骨重建的稳态。由于衰老、雌激素缺乏等因素引起体内氧化体系与抗氧化体系之间的平衡被打破,导致活性氧生成增多,发生氧化应激。近年来的研究发现活性氧所引起的氧化应激反应对骨重建过程中的骨形成和骨吸收均有重要的影响,机体内积累产生的过多活性氧通过对细胞因子、酶活性以及信号通路的调节,干预核内基因的转录表达,最终导致骨髓间充质干细胞、成骨细胞、骨细胞和破骨细胞增殖凋亡或分化功能的异常,使骨重建失衡,形成以骨吸收为主的代谢性骨病,从而引起骨质疏松症。因此,笔者就近年来氧化应激的产生及氧化应激对骨髓间充质干细胞、成骨细胞、骨细胞、破骨细胞的影响,骨质疏松症的抗氧化治疗等方面作一综述,对进一步认识氧化应激在骨重建中的生理病理学机制有着重要意义。     

血管束骨内移植重建离断骨血液循环的实验研究

为了研究离断骨在一定应力状态下植入血管束后，能否重建骨的血液循环以及血管束移植对成骨的影响，作者将１８只成年杂种犬胫骨两端截断，切除实验骨区的骨膜，胫骨离断面填入硅胶膜以阻断两侧干骺端血供，将离骨段固定于原位；分离出胫前动静脉束并结扎。随机分成３组，实验Ａ组（ｎ＝７）：结扎后的血管直接植入骨髓腔；Ｂ组（ｎ＝７）：血管束打孔后植入骨髓腔；Ｃ组（ｎ＝４）：离断后的胫骨段内不植血管，作为对照。术后分别于不同时间进行血管造影、血管筑型、大体及组织学和电镜观察。实验结果显示：原实验骨因初期缺血均发生无菌性坏死；在一定应力状态下，血管束骨内移植后，植入的血管再生旺盛，骨髓腔内成骨活跃。结果表明，血管束骨内移植后可重建坏死骨的血液循环，膜性化骨和软骨内化骨在成骨因素中均发挥着重要作用。     

A quantitative study of the effects of prolonged calcitonin treatment on alveolar bone remodelling in the golden hamster

This study was carried out on adult golden hamsters, to correlate the effects of porcine calcitonin on serum Ca and P concentrations with changes in osteoclastic resorption of bone. After 1 month of treatment with 5 MRC units/kg/day, there was little effect on these parameters. On the other hand, the hormone appears to have an effect on the remodelling sequence, as indicated by a large and very significant decrease in the extent of resorption lacunae unoccupied by osteoclasts. It is suggested that the duration of the reversal phase, separating the end of active resorption from the beginning of active bone formation in each remodelling focus, is greatly decreased. This shortening is associated with a prolongation oft he bone formation phase, and the extent of osteoid tissue is markedly and proportionally increased in the treated animals. After a prolonged administration, calcitonin does not seem to impede the formation of new osteoclasts, their number being only slightly diminished, but it remains possible that it does continue to inactivate these cells. The effect on the bone remodelling sequence could be either due to direct action on the osteoblasts or their precursor cells, or an indirect action via the osteoclasts.     

Skeletal actions of intermittent parathyroid hormone: effects on bone remodelling and structure

Intermittent administration of parathyroid hormone peptides has anabolic skeletal effects and reduces fracture risk in postmenopausal women with osteoporosis but the cellular and structural mechanisms by which these effects are mediated have not been fully established. In cancellous and endocortical bone, there is evidence that both modelling and remodelling-based formation contribute to the increase in bone mass although the contribution of these at different time points in the response to PTH has not been established. Despite the large increase in spine bone mineral density, however, significant increases in iliac crest cancellous bone volume and trabecular thickness have not been consistently demonstrated, possibly reflecting site-specific differences in PTH-induced skeletal effects and/or the large sampling and measurement variance associated with assessment of iliac crest cancellous bone volume and structure. In iliac crest cortical bone, increased cortical thickness has been demonstrated, due at least in part to increased endosteal bone formation; there is also some evidence for increased formation on periosteal surfaces. At some sites an increase in cortical porosity may also occur and the overall effects on cortical bone strength, particularly at the hip, remain to be established. Studies in iliac crest bone indicate a trend towards a lower mineralisation density of bone matrix and increased heterogeneity of mineralisation, consistent with new bone formation. In addition, there is a reduction in mineral crystallinity and a shift towards more divalent collagen cross-links, indicating a change towards a younger bone profile.

The potential clinical implications of these effects on bone are currently unknown. The stimulatory effect of PTH peptides on bone formation may favour their use in low turnover bone disease and in states of advanced bone loss. Furthermore, if beneficial effects on cortical bone strength are confirmed, efficacy at non-vertebral sites might be superior to those observed with antiresorptive drugs. Better definition of the effects of intermittent PTH administration on cancellous and cortical bone remodelling and structure at different skeletal sites may inform these speculations and is an important area for future research.     

Computational bone remodelling simulations and comparisons with DEXA results.

Femoral periprosthetic bone loss following total hip replacement is often associated with stress shielding. Extensive bone resorption may lead to implant or bone failure and complicate revision surgery. In this study, an existing strain-adaptive bone remodelling theory was modified and combined with anatomic three-dimensional finite element models to predict alterations in periprosthetic apparent density. The theory incorporated an equivalent strain stimulus and joint and muscle forces from 45% of the gait cycle. Remodelling was simulated for three femoral components with different design philosophies: cobalt-chrome alloy, two-thirds proximally coated; titanium alloy, one-third proximally coated; and a composite of cobalt-chrome surrounded by polyaryletherketone, fully coated. Theoretical bone density changes correlated significantly with clinical densitometry measurements (DEXA) after 2 years across the Gruen zones (R2>0.67, p<0.02), with average differences of less than 5.4%. The results suggest that a large proportion of adaptive bone remodelling changes seen clinically with these implants may be explained by a consistent theory incorporating a purely mechanical stimulus. This theory could be applied to pre-clinical testing of new implants, investigation of design modifications, and patient-specific implant selection.     

Effect of ovariectomy on intraosseous vascularization and bone remodelling in rats: Action of tiludronate

In order to study the action of tiludronate on the changes in intraosseous vascularization induced by ovariectomy, and to link these effects to those observed in bone remodelling, 30 female Sprague-Dawley rats (age 40 weeks) were studied. Ten rats were sham-operated and treated by vehicle, 10 rats were ovariec-tomized and treated by vehicle, and 10 rats were ovariectomized and treated orally with tiludronate, 0.16 mmol/kg/per day, 3 days a week for 16 weeks, from the day following ovariectomy. The rats were killed after 4 months, and a histomorphometric study and quantification of intraosseous vessels carried out on the sixth lumbar vertebra. The area of the intraosseous sinusoidal capillaries increased after ovariectomy, which also induced a moderate increase in resorption surfaces and osteoid surfaces leading to a decrease of 40% in the trabecular bone volume at the lumbar spine level. This bone mineral loss was completely prevented by tiludronate, which normalized the bone turnover. However, tiludronate was without any effect on intraosseous vascularization. These results indicate that the surface area of the intraosseous sinusoidal capillaries was correlated positively with resorption surfaces and negatively with trabecular bone volume and the number of bone trabeculae. In these experimental conditions, an inhibitor of bone resorption can exert its positive effect on bone mass without normalization of vascularization.     

Bone morphogenetic protein 2 accelerates osteointegration and remodelling of solvent-dehydrated bone substitutes

Introduction lt was the purpose of this study to investigate how bone morphogenetic protein 2 (BMP-2) influences remodelling and the biomechanics of solvent-dehydrated bone in the long run. Furthermore, the early influence of this growth factor on the substitute was investigated.Materials and methods Using a weight-bearing animal model, solvent-dehydrated bone was implanted in the tibial head of merino sheep (n=12) after being loaded with BMP-2 (100 g/100 l). At 4 weeks (n=6) and 9 months (n=6) after surgery, histomorphological, histomorphometrical and biomechanical investigations were performed.Results At 9 months after implantation of BMP-2-loaded specimens, the bone per tissue volume was high, with levels above those of physiological cancellous bone. The amount of remaining solvent-dehydrated bone was markedly decreased, and in contrast, the amount of newly formed bone was extremely high. The specimen degradation had already occurred within the first 4 weeks after implantation, showing no further impact throughout the 9-month period. Biomechanical investigations at 9 months after implantation demonstrated a yield strength which achieved levels at least equivalent to physiological cancellous bone. BMP-2 showed no significant impact on the biomechanical properties after 4 weeks, compared to specimens prior to implantation.Conclusion BMP-2 predominantly has an impact on the early implant degradation as well as bone formation, which leads to an almost completed bone remodelling of the solvent-dehydrated specimen within the study period of 9 months.     

Normal bone physiology,remodelling and its hormonal regulation

Bone is a complex tissue, which has a number of mechanical and physiological functions. The maintenance and repair of bone is ensured by a constant cycle of turnover and remodelling. The control of this process is equally complex and is regulated by both mechanical and biological controls.     

骨质疏松性骨折与骨密度相关性实验研究

目的通过建立SD大鼠骨质疏松模型,研究骨质疏松性骨折临界载荷、骨刚度系数与骨密度间的关系。方法取SD大鼠40只,行骨质疏松造模,造模后3个月测定活体股骨骨密度,根据骨密度的高低分为4组,每组10只。分组后取大鼠股骨行三点弯曲试验,记录骨折临界载荷、骨刚度系数,并进行统计学分析。结果 A组骨密度(0.241±0.009)g/cm2,B组(0.226±0.011)g/cm~2,C组(0.211±0.009)g/cm2,D组(0.193±0.008)g/cm~2,4组骨密度差异有统计学意义(F=12.980,P=0.012)。A组骨折临界载荷(226.80±9.13)N,B组(212.11±7.96)N,C组(204.08±8.70)N,D组(193.60±8.08)N,4组骨折临界载荷差异有统计学意义(F=13.483,P=0.020);且A组骨折临界载荷B组(t=-2.112,P=0.043),B组骨折临界载荷C组(t=-2.978,P=0.006),C组骨折临界载荷D组(t=-2.631,P=0.014)。A组骨刚度系数(526.37±8.86)N/mm,B组(531.10±12.01)N/mm,C组(490.57±9.76)N/mm,D组(465.88±5.41)N/mm;A组与B组骨刚度系数比较差异无统计学意义(t=-1.852,P=0.074),B组骨刚度系数C组(t=-3.369,P=0.001),C组骨刚度系数D组(t=-2.539,P=0.019)。结论当骨密度降低到一定程度后,骨密度的下降与骨折临界载荷、骨刚度系数呈正相关,骨密度减少导致骨折风险增高。     

Comparison of periprosthetic bone remodelling after implantation of anatomic and straight stem prostheses in total hip arthroplasty

Introduction Total hip arthroplasty changes bone loading conditions in the proximal femur and induces adaptive remodelling of the periprosthetic bone. These remodelling processes depend on many implant-specific qualities, e.g. material and elasticity of the stem. The objective of this study was to investigate the effect of the stem design on periprosthetic bone remodelling after insertion of an anatomic stem with proximal fixation and the direct comparison to a straight stem prosthesis. Materials and methods In a prospective study, the changes in periprosthetic bone mineral density (BMD) after implantation of 68 CTX-S anatomic and 22 PPF straight stem prostheses were assessed in the first post-operative year by means of DEXA and zone analysis by Gruen (Clin Orthop 141:17–27, 1979) “Modes of failure” of cemented stem-type femoral components: a radiographic analysis of loosening.. Furthermore all patients with CTX-S prostheses were monitored in the second post-operative year. The correlation of adaptive bone remodelling and the systemic bone density was also investigated. Results In the distal one-third of the straight stem prosthesis, a clearly greater, although not significant, hypertrophy of the periprosthetic bone was observed. No differences in the extent of bone loss between the two prostheses in the regions of interest (ROI) of the proximal bone were observed. The greatest decrease in BMD was registered in the medial femoral neck in both groups. Bone atrophy decreased progressively as the ROI moved distally, ending in a slight increase in BMD in the distal ROI. No significant changes in periprosthetic BMD occurred in the second post-operative year. A strong positive correlation in the regions with the greatest BMD decrease with the systemic BMD was ascertained. Conclusion After implanting a CTX-S prosthesis, as opposed to PPF prostheses, a different pattern of periprosthetic bone remodelling with a slighter hypertrophy of the distal periprosthetic parts was observed. This implies that the extensive proximal, more physiological bone loading of the anatomic stem as well as the removal of less bone while implanting the stem reduces the negative effects of unphysiological strain distribution and stress shielding. The BMD loss in the medial proximal neck cannot be avoided with this stem design either. The lack of significant BMD changes in the second post-operative year suggests that a stabilisation of bone remodelling processes occurs.     

切除卵巢对骨基质明胶修复大鼠颅骨缺损成骨效能的影响

目的　探讨实验性骨质疏松状态对骨基质明胶修复骨缺损成骨效能的影响。方法　将 6 8只雌性SD大鼠随机分为去卵巢组和对照组。 90d后两组各抽取 10只测定骨密度以确定骨质疏松模型的建立。其余 4 8只大鼠制备直径 8mm颅骨极量骨缺损并同期植入骨基质明胶颗粒。植入术后 2 1和 5 6d两组每次分别处死 12只大鼠 ,通过不脱钙组织磨片、四环素荧光示踪及骨组织计量学动态参数测定、扫描电镜和X射线显微分析技术观察骨缺损区修复情况。结果　骨密度测定指标显示 ,去卵巢 90d后骨质疏松状态建立。骨基质明胶植入术后 2 1d ,均有新骨在两实验组骨缺损内形成 ,去卵巢组新骨形成较少 ,四环素标记成骨区域较稀疏。植入术后 5 6d ,对照组骨缺损基本修复 ,去卵巢组骨缺损部分区域为纤维结缔组织充填。植入术后 2 1d、5 6d荧光双标间距和平均矿化沉积速率均较对照组低 ,差异有统计学意义 (P <0 0 1)。骨缺损区新生骨痂的钙磷比值定量分析 ,去卵巢组均低于对照组 ,差异有统计学意义 (2 1d :0 4 892± 0 0 342、0 5 4 75± 0 0 2 0 4 ,P <0 0 1;5 6d :1 0 95 0± 0 0 4 37、1 195 5± 0 0 4 6 3,P <0 0 1)。结论　实验性骨质疏松降低了骨基质明胶的成骨效能。雌激素可能在生物骨替代材料参与的骨重建中发挥重要     

钻孔复合人工骨体内植入成骨的实验研究

目的探索符合临床需要的复合人工骨移植材料。方法以磷酸三钙＋多孔羟基磷灰石 (TCP＋ HA)为载体 ,分为钻孔、未钻孔及空白对照三组。自成年新西兰兔股骨转子部取得骨髓基质细胞进行传代培养,所得骨髓基质细胞再与钙磷陶瓷载体复合培养制成复合人工骨。然后植入兔背部肌肉内,分别于手术后第 2、 4、 8、 12周取材。利用组织学和电子显微镜等方法观察细胞在载体内的生长、复合人工骨植入肌肉内的成骨等情况,以及载体钻孔对细胞长入和成骨的影响。结果电子显微镜观察显示,传代的骨髓基质细胞与载体共同培养生长良好,并可长入钻孔载体内部。大体标本可见,复合人工骨植入后,人工骨与周围肌肉连接,无包膜形成。组织学观察显示,术后第 2周组织和血管长入;术后第 4～ 8周有少量骨形成;术后第 12周板层骨形成。三组均无淋巴细胞浸润。与未钻孔者比较,钻孔人工骨的细胞、组织和血管向中心部位生长速度快,中心部位成骨多且更均匀。结论磷酸三钙＋多孔羟基磷灰石载体具有良好的生物相容性及骨传导性;骨髓基质细胞具有成骨能力;载体钻孔有利于增加新骨形成的速度和数量,使成骨更为均匀。