锶羟基磷灰石生物活性骨水泥应用于髋关节置换的研究

目的探讨锶羟基磷灰石（St-HA）生物活性骨水泥应用于髋关节置换的可行性。方法对Sr—HA生物活性骨水泥的力学特性及其在体应用于髋关节置换及髋关节翻修的生物学特性与聚甲基丙烯酸甲酯（PMMA）骨水泥进行比较及评价。结果Sr-HA生物活性骨水泥与PMMA骨水泥抗压缩强度相似，但其断裂韧度却高于PMMA骨水泥；在体研究表明Sr-HA生物活性骨水泥能与骨形成骨性融合，其与骨界面的剪切力明显大于PMMA骨水泥。结论Sr—HA生物活性骨水泥具有替代PMMA骨水泥应用于髋关节置换的潜力。     

生物活性骨水泥的孔隙率与骨水泥全髋关节置换术后假体早期位移的相关性研究

[目的]比较全髋关节置换术后早期新型生物活性骨水泥即含锶羟基磷灰石骨水泥(Sr-HA)与传统的聚甲基丙烯酸甲酯骨水泥(PMMA)对假体固定的效果.[方法]从2008年5月～2009年12月在香港玛丽医院行全髋关节置换术的9例(10膝)患者随机分为观察组和对照组,分别使用Sr-HA骨水泥与PMMA骨水泥同定股骨柄,于术后1周、3个月、6个月及12个月随访使用放射立体照相测量分析技术(RSA)测量股骨柄相对于股骨的位移,记录Harris髋关节评分,并于实验室使用显微CT扫描测鼍两种骨水泥的孔隙率进行比较.[结果]所有患者手术经过顺利,无血管神经损伤、肺栓塞等并发症.RSA结果显示Sr-HA组有3例假体的下沉均超过1 mm,而PMMA组假体的下沉全部在1 mm以内.两组患者的Harris髋关节评分在术后均有明显改善.显微CT扫描结果显示Sr-HA骨水泥的孔隙率高于PMMA骨水泥,两者之间差异有统计学意义(P＜0.01).[结论]两组患者术后均无明显临床症状,含锶羟基磷灰石骨水泥相对较高的孔隙率可能是导致全髋关节置换术后早期假体位移的原因.     

骨水泥振动器的研制及其对骨水泥-骨界面影响的实验研究

目的 评价骨水泥振动器对提高骨水泥-骨界面微嵌合强度的效果及临床意义.方法 取新鲜成猪股骨100根,随机分成6组;力学测试组:抗拉力实验组(A1)与对照组(A2)和抗压力实验组(B1)与对照组(B2)模型每组各20个;影像学测试组:实验组(C1)与对照组(C2)模型各10个.对模型进行力学及影像学检测,比较实验组与对照组骨水泥-骨界面的微嵌合强度.结果 力学及影像学测定显示实验组骨水泥-骨界面微嵌合强度均高于对照组,二者比较差异具有显著统计学意义(P＜0.01).结论 骨水泥振动器能显著提高骨水泥-骨界面微嵌合强度,对于减少人工假体远期无菌性松动具有一定的意义.     

骨水泥型关节假体骨水泥-骨界面相关研究进展

骨水泥型关节假体无菌性松动是影响假体使用寿命的主要问题。假体松动翻修术中取出的金属假体柄研究提示,柄的松动主要发生在骨水泥与骨髓腔内壁界面而非骨水泥与假体柄界面。骨水泥-骨界面的力学强度主要取决于界面区域骨形态和骨水泥与骨之间的交锁程度,影像学、力学测试、有限元分析等研究显示骨水泥-骨界面的扭转力、剪切力、混合力及蠕变-疲劳应力条件下强度变化等微力学变化与假体松动相关。界面反复微动引起的摩损碎屑颗粒和离解产生的微小颗粒物质,引起一系列免疫反应及机体自身对这些颗粒的反应,促使假体周围发生骨溶解,加剧假体松动。该文就骨水泥-骨界面微力学变化特点及假体松动机制作一综述。     

载阿仑膦酸钠骨水泥抑制钛磨屑诱导的假体周围骨溶解

目的 比较载阿仑膦酸钠丙烯酸骨水泥与皮下注射阿仑膦酸钠抑制钛磨眉诱导的骨溶解的效果.方法 48只成年雄性新西兰兔随机均分为无钛磨屑且无阿仑膦酸钠组(A组),有钛磨屑注射且无阿仑膦酸钠组(B组),钛磨屑分别注射0.1%、0.5%、1.0%载阿仑膦酸钠丙烯酸骨水泥组(C、I)、E组),钛磨屑注射且皮下手射阿仑膦酸钠组(F组),每组8只.将载阿仑膦酸钠骨水泥植入兔股骨远端.制备磨屑诱导骨溶解动物模型.术后8周对股骨行组织形态学分析、骨密度(bone mineral density,BMD)测定及界面力学测试结果 B组假体周围可见明显的骨溶解,而C、D、E、F组骨溶解明显少于B组.B组假体周围BMD和骨-骨水泥界面抗剪强度分别较A组下降17%和56%;D组假体周围BMD和界面抗剪强度较B组分别增加29%和62%;E组假体周围BMD和界画抗剪强度较B组分别增加37%和29%;F组假体周围BMD和界面抗剪强度较B组分别增加51%和69%;C组、D组、E组分别与F组比较,假体周围BMD和界面抗剪强度的差异均无统计学意义.结论 载阿仑瞵酸钠丙烯酸骨水泥与皮下注射阿仑瞵酸钠均可在一定程度上抑制磨屑诱导的骨吸收,增强界画抗剪强度.     

骨水泥型与非骨水泥型双动人工股骨头治疗老年股骨颈骨折的对比研究

[目的]对比观察骨水泥固定型与非骨水泥固定型双动人工股骨头置换治疗老年股骨颈骨折的临床差异.[方法]按入院单数和双数日期把老年股骨颈骨折患者[年龄70～93岁,平均(76.69±5.38)岁]分为两组,骨水泥组67例,非骨水泥组64例,分别采用骨水泥型和非骨水泥型人工股骨头置换治疗.记录两组手术时间、术中出血量,术后伤口引流量、下地负重时间以及患髋Harris评分等,进行分析比较.[结果]与非骨水泥组相比,骨水泥组在下地负重时间、早期(3个月)髋功能恢复方面优势显著,其余方面差异不显著.在最终(24个月)随访时,骨水泥组与非骨水泥组Harris评分分别为87.61±4.77和86.95±5.71.[结论]两组患者术后近期疗效满意,但骨水泥组在早期负重和功能恢复方面具有优势.     

骨水泥振动器的运用对骨水泥-骨界面微嵌合的影响

目的 评价骨水泥振动器对提高骨水泥-骨界面的整合效果及临床意义. 方法 取新鲜成猪股骨16根,随机分成两组,实验组(A组)与对照组(B组)模型各8根.猪股骨髓腔内应用骨水泥振动器进行骨水泥灌注后(对照组灌注骨水泥不经振动),对每组实验模型进行硬组织切片,每根股骨模型等距选取3个层面,HE染色后在体视显微镜下观察,经电脑Motic Med 6.0数码医学图像分析系统分析测量骨水泥渗透入松质骨腔的厚度,记为渗透厚度,将所得数值进行统计学分析,对比振动组与对照组的骨水泥灌注效果. 结果 体视显微镜下显示实验组骨水泥与骨小梁之间结合紧密,骨水泥在松质骨腔内充填均匀一致,骨水泥与骨小梁之间的结合紧密.对照组骨水泥向松质骨腔内渗透欠佳,在松质骨腔内充填不均匀.结果显示实验组骨水泥渗透厚度高于对照组,差异均具有统计学意义(P＜0.05). 结论 骨水泥振动器能够使骨水泥在骨髓腔内弥散更加均匀,能够促进骨水泥向骨小梁内渗透,从而增加骨水泥与骨小梁之间的微嵌合.     

非骨水泥与骨水泥长柄翻修股骨假体周围骨折比较

[目的]比较股骨假体周围骨折(periprosthetic femoral fracture, PFF)翻修术使用Zweymull?er生物型长柄与传统骨水泥假体的临床效果。[方法]回顾性分析2017年6月～2019年6月本院翻修置换术治疗的PFF患者60例,其中,32例接受Zweymüller生物型长柄股骨假体翻修,28例接受骨水泥型长柄股骨假体翻修。比较两组围手术期、随访与影像资料。[结果]非水泥组手术时间、术中出血量、术后下地行走时间、住院时间均显著优于骨水泥组(P0.05)。非水泥组完全负重活动时间显著早于骨水泥组(P0.05)。与术后1个月相比,末次随访时,两组患者VAS评分显著下降(P0.05),而Harris评分和髋伸屈ROM显著增加(P0.05)。相应时间点,非水泥组VAS评分、Harris评分和髋伸屈ROM均显著优于骨水泥组(P0.05)。影像方面,末次随访时,非水泥组股骨前倾角、颈干角和股骨前弓角均优于骨水泥组(P0.05)。非水泥组骨折愈合时间显著早于骨水泥组(P0.05)。[结论]对于股骨假体周围骨折的翻修置换术,采用非水泥假体的临床结果优于骨水泥型假体。     

多孔磷酸钙/骨基质明胶复合骨水泥修复兔腰椎骨缺损的实验研究

目的探讨多孔磷酸钙/骨基质明胶复合骨水泥(以下简称多孔复合骨水泥)修复兔腰椎骨缺损的效果。方法采用Urist等的方法制备成年新西兰兔骨基质明胶(bone matrix gelatin,BMG),参考W/O/W复乳法制作聚乳酸-羟基乙酸共聚物[poly(lactic-co-glycolic)acid,PLGA]空白微球,将PLGA空白微球和BMG与磷酸钙骨水泥(calcium phosphate cement,CPC)复合,构建多孔复合骨水泥。通过体外抗溃散观察、孔隙率测定及生物力学试验,观察其理化特性;并以CPC作对照。取30只2月龄新西兰兔,制备L_3椎体大小为4 mm×3 mm×3 mm的骨缺损后,分别填入多孔复合骨水泥(实验组,n=15)和CPC(对照组,n=15)。术后第4、8、12周,X线片观察骨融合情况,micro-CT分析骨密度(bone mineral density,BMD)、骨体积分数(bone volume fraction,BVF)、骨小梁厚度(trabecular thickness,Tb.Th.)、骨小梁数量(trabecular number,Tb.N.)和骨小梁分离度(trabecular spacing,Tb.Sp.),组织学观察新生骨形成情况。结果两种骨水泥均有较好抗溃散性,多孔复合骨水泥孔隙率为55.06%±1.18%,抗压强度为(51.63±6.73)MPa,与CPC的孔隙率(49.38%±1.75%)以及抗压强度(63.34±3.27)MPa相比,差异有统计学意义(t=4.254,P=0.006;t=2.476,P=0.034)。X线片观察示,随时间延长,两组材料与宿主之间的边界逐步模糊,且实验组第12周时边界已消失、对照组仍可见。micro-CT检测各时间点实验组BMD、BVF、Tb.Th.、Tb.N.以及Tb.Sp.与对照组相比,差异均有统计学意义(P0.05)。组织学观察示,随时间延长,两组植入材料中均见新骨生长,其中实验组新生骨与宿主骨形成骨性连接,优于对照组。结论多孔复合骨水泥具有骨诱导活性和骨传导双重作用,可以有效促进兔腰椎骨缺损修复重建。     

磷酸钙骨水泥/rhBMP-2修复犬股骨头软骨下骨缺损重建力学性能的实验研究

目的:研究应用组织工程技术修复股骨头骨缺损后力学性能的变化.方法:20只犬随机分为A、B两组,各组对侧作为C组.用活门法(Trapdoor)造骨缺损模型,通过活门在骨缺损区A组植入磷酸钙骨水泥/rhBMP-2;B组植入多孔磷酸钙骨水泥;C组缺损区不做处理.回植活门区软骨瓣与骨关节面平齐.16周后进行组织标本观察、组织学检查、生物力学测试.结果:A组,关节面光滑,无活门区软骨瓣塌陷,活门区软骨瓣色泽与周围关节软骨相近,缺损区磷酸钙骨水泥几乎完全吸收由新生骨组织替代,力学强度明显高于B、C组;B组,6只软骨瓣塌陷(1～3.6mm),软骨瓣色苍白,质软易碎,力学强度低于A组,骨缺损区尚残存部分磷酸钙骨水泥;C组,几乎所有软骨瓣塌陷(1.6～5.5mm),色灰白,软易碎,表面有细小的裂纹,力学强度最低,缺损区有纤维组织填充.结论:新型生物活性材料多孔磷酸钙骨水泥/rhBMP-2能明显加快股骨头软骨下骨缺损的修复并有效的恢复股骨头的力学性能.     

The biological fixation strength of the bone particle impregnated bone cement]

This article reports the result of the comparative study on the biological fixation strength of two kinds of bone particle impregnated bone cement. Organic and inorganic bone particle impregnated bone cement were implanted into alternative side of the upper femurs of New Zealand rabbits. The cancellous bone and cortical bone segments of the implanted femurs removed at intervals of 1, 2 and 3 months after operation were subjected to push-out test. In cancellous bone segment, shearing strength of cement-bone interface was increased gradually, but no significant difference between these two kinds of cement after 3 months operation. In cortical bone segment, the interface shearing strength was lower than that of the cancellous bone, but it increased rapidly from 1 month, especially for the organic bone particle bone cement, after 3 months operation the interface shearing strength had a significant difference between the two kinds of cement. More prominent biological fixation effect showed in the organic bone particle group.     

Comparative study of human cancellous bone remodeling to titanium and hydroxyapatite-coated implants

The human cancellous bone response was compared in weight-bearing porous hydroxyapatite (HA) and titanium-coated implants placed in the distal medial femoral condyles of consenting staged bilateral knee patients. The Institutional Review Board approved study quantified the amount of bone ingrowth, the mineral apposition rate, and the bone mineral content. Results showed that the osteoconductive HA coating increased the amount of bone ingrowth by 8% (P=.018). The HA coating did not effect the mineral apposition rate of the bone but had an 8% lower bone mineral content at the implant interface (P=.042). The influence of HA coatings on human cancellous bone appears highly focal along the coating surface. Gaps of 50–500 μm filled with fibrous connective tissue were observed along the porous-coated surfaces of both implant types suggesting that HA coatings still require precision placement adjacent to human cancellous bone.     

Stress transfer at the femoral bone/bone cement interface as a function of the cement thickness

Summary When a cement canal prosthesis is used as the femoral component in total hip replacement (THR), the penetration depth of the bone cement can be varied according to the cement implantation pressure. Using experimental data which give a relation between the pressure applied to the cement at implantation and the resulting shape of the cement layer, a three-dimensional finite element study was performed to calculate the stress distribution at the bone/bone cement interface. The calculations show that the interface stresses increase with increasing depth of penetration by the cement layer. The explanation of this effect is that as the bone cement penetrates further into the cancellous bone, the cancellous bone is stiffened and can no longer act as a soft interposition between cortical bone and bone cement. From these results and from the clinical requirement that as little bone as possible be destroyed in any kind of alloarthroplasty, we conclude that the penetration depth of bone cement into cancellous bone in THR should be minimized to the depth necessary in order to achieve sufficient initial stability of the implant. The results show that a cement-canal prosthesis meets these requirements if a cement implantation pressure of 1.0 bar is used.     

Effect of modification of hydroxyapatite/collagen composites with sodium citrate, phosphoserine, phosphoserine/RGD-peptide and calcium carbonate on bone remodelling

This study describes the early interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (HA/Coll) and its modifications with sodium citrate (CI), calcium carbonate (CA), phosphoserine (P) and phosphoserine plus RGD-peptide (RGD). Cylindrical implants of HA/Coll and its modifications were inserted into the tibia of Wistar rats. We analysed 6 specimens per group at days 2, 4, 7, 14 and 28. CI, P and RGD modifications showed improved material properties (finer microstructure and higher compressive strength) compared to CA and HA/Coll implants. The powder X-ray diffraction (XRD) showed that the addition of P and CI led to an increase of alpha-TCP peaks while the diffraction patterns of the non-modified cement (HA/Coll) were quite similar with that of natural bone. All of the implants healed without adverse reactions. A significantly higher number of TRAP-positive osteoclasts were observed around CI, RGD and P on day 7 compared to CA and HA/Coll. Around CI, P and RGD a significantly delayed increase of ED1-positive mononuclear cells was detected. The amount of direct bone contact after 28 days was significantly higher around CI, P and RGD compared to CA and HA/Coll implants. The addition of CI, P and RGD appears to enhance bone remodelling at the early stages of bone healing, leading to increased bone formation around HA/Coll composite cements.     

Penetration of acrylic bone cements into cancellous bone

The depth of penetration of five commercial acrylic bone cements into cancellous bone was measured in vitro. Under standard, idealized conditions, cement penetration was found to vary significantly with different cements. Penetration was critically influenced by the coarseness of the cancellous bone and increased directly with the effective volume of the "cells" within the osseous matrix. An inverse correlation was determined between the mean cement viscosity during flow into the bone and final penetration depth. The dough time, set time and working time of each acrylic formulation was found to have no significant effect upon the depth of cement penetration. It is suggested that in addition to the techniques adopted for introduction of cement to the bone, the selection of the bone cement itself may critically influence the incidence of late loosening following total joint replacement.     

A study of intrusion characteristics of low viscosity cement Simplex-P and Palacos cements in a bovine cancellous bone model

Aseptic loosening is the most common long-term complication of cemented total hip arthroplasties (THA). The functional longevity of these implants depends on the bone-cement interface. The influence of cement injection pressure, type of cement, ambient temperature, chilling of the monomer, and centrifugation of cement-on-cement intrusion depth was investigated in specimens of bovine cancellous bone. In order to validate the bovine model for comparative purposes relative to use in man, a linear relationship between human and bovine cancellous bone was first demonstrated for various porosities and cement intrusion depth. Three cements (Low Viscosity Cement [LVC], Simplex-P, and Palacos) were intruded at three different pressures (20, 40, and 60 PSI) at the same ambient temperature and relative humidity into commercially prepared plugs of bovine cancellous bone. Cement intrusion depth was proportional to injection pressure for all three cements, but was significantly different for each cement at a given pressure. At 20, 40, and 60 PSI, Palacos had a cement intrusion depth of 1.4, 2.4, and 2.8 mm respectively, while the figures for Simplex-P were 2.2, 4.2, and 5.0 mm, and for LVC were 8.0, 12.0, and 14.6 mm. Ambient temperature had an inverse relationship with cement intrusion depth for all three cements given the same experimental conditions. Chilling the monomer increased the intrusion of Simplex-P to 5.8, 8.2, and 12.7 mm at 20, 40, and 60 PSI injection pressure respectively. Simplex-P intrusion depth was not modified by cement centrifugation at any of the three injection pressures tested.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo response of bone defects filled with PMMA in an ovine model

The use of PMMA cement is common in arthroplasty for cemented fixation and defect filling. Concerns remain regarding effects of cement curing temperature on the viability of cancellous bone. In this study we filled surgically-created defects (mean volume 0.585±0.251 mL) in the cancellous bone of the distal femur and proximal tibia of 6 sheep with PMMA and measured temperature changes in surrounding bone whilst the cement cured, using 3 thermocouples per defect. Animals were euthanised at 3 (n=3) and 12 (n=3) weeks postoperatively and the bone-cement interface assessed histologically. Despite mean maximum temperatures of 49.3±10.2 °C (range: 40.9 °C - 82.2 °C) thermonecrosis was not a common histological feature at either timepoint. The exposure of bone to high cement temperatures in this study has not led to bone necrosis and/or tissue damage.     

Synergistic effects of HBO and PRP improve bone regeneration with autologous bone grafting

Bone defects remain a challenge for patients and orthopaedic surgeons. Autologous transfer of cancellous bone grafts remains the standard of care. However, in recent years various osteoinductive substitute materials, such as platelet rich plasma (PRP) and hyperbaric oxygen therapy (HBO) have been shown to improve bone healing. This study evaluates the effects of a combined application of PRP and HBO with autologous bone grafting in an animal model.In 48 New Zealand White rabbits bone defects at the radius were filled with autologous bone harvested at the iliac crest. This was combined with application of autologous PRP and/or HBO treatment for the duration of this study. After 3 and 6 weeks histomorphometric, immunohistochemical and radiologic evaluations were performed.All animals tolerated the treatment well. Improved bone regeneration was shown in all groups at 6 weeks compared to 3 weeks. Additional application of PRP and HBO resulted in an increase in new bone formation and increased neovascularization at 3 and 6 weeks. There was no statistical significant difference between PRP and HBO application in these regards. A combinatory use of PRP and HBO resulted in an increased bone regeneration and neovascularization compared to all other groups.This study provides evidence for an improvement of bone regeneration with the combinatory application of PRP and HBO to autologous cancellous bone grafts in a model of weight bearing bone defects in rabbits. Also synergistic effects of these two measures on angiogenesis were evident.     

松质骨螺钉骨水泥强化的生物力学和组织学研究

目的通过动物实验观察不同骨水泥强化松质骨螺钉的生物力学和组织学变化动态,为骨质疏松骨折患者内固定提供理论基础。方法在10只杂种犬胫骨近端制作松质骨螺钉植入的动物模型,分别采用碳酸化羟基磷灰石水泥(CHC)和聚甲基丙烯酸甲酯(PMMA)强化,分别于术后5d、4、8、12和16周处死动物,观察螺钉拔出的生物力学和组织学变化。结果CHC强化的螺钉拔出力随手术后时间的延长而逐渐升高,16周时达到(512.5 14.5)N,而PMMA强化组螺钉拔出力则随手术后时间的延长而逐渐降低。CHC-骨界面结合紧密,并且随时间延长出现CHC降解和骨长入,而PMMA-骨界面形成一层纤维组织。结论CHC强化能够提高松质骨螺钉植入体内的稳定性,并且随植入时间延长而逐渐升高。