携载rhBMP-2微球的新型复合人工骨的释药及成骨活性研究

目的 制备一种具有良好降解性和成骨活性，可注射的自凝固新型骨修复材料。方法制备携载rhBMP-2的聚乳酸与聚乙醇酸共聚物（PLGA）微球，并将其与rhBMP-2／磷酸钙骨水泥（CPC）复合。制备出rhBMP-2／PLGA微球／CPC复合人工骨。测定了复合材料释药速度，将复合材料及rhBMP-2-CPC分别植入兔双侧股骨髁骨缺损区域，通过X线、组织学观察比较不同时期材料的降解及成骨情况。结果 复合材料各时间点的体外释药量均大于单纯rhBMP-2／CPC组．与单纯rhBMP-2／CPC材料相比较，复合材料植入体内后不同时间点材料的降解和新骨生成均高于单纯rhBMP-2／CPC植入组。结论 rhBMP-2／PLGA微球的掺入可明显加快rhBMP-2的释放。提高材料的降解速度和成骨活性。     

多孔磷酸钙人工骨与重组人骨形成蛋白2复合修复骨缺损的实验研究

目的研究多孔磷酸钙人工骨（porous calcium phosphate cement，PCPC）与重组人骨形成蛋白2（recombinant human bone morphogenetic protein2，rhBMP-2）复合后体外的缓释作用及其对兔骨缺损的修复作用。方法采用物理吸附法将rhBMP-2（0．4mg）溶液吸附至PCPC中，制备成PCPC／rhBMP-2复合材料。冻干后，扫描电镜观察复合材料内部形态。以包覆壳聚糖的PCPC／rhBMP-2为实验组，单纯PCPC／rhBMP-2为对照组，测试在模拟体液中的rhBMP-2缓释行为。取新西兰大白兔12只，股骨远端制成直径4．2mm，深5．0mm的骨缺损模型。将包覆壳聚糖的PCPC／rhBMP-2复合材料修复骨缺损作为实验组，以植入单纯PCPC作为对照组。术后观察动物一般情况，于4周和8周取材行X线片和组织学观察。结果扫描电镜显示PCPC／rhBMP-2复合材料孔隙中吸附了大量的rhBMP-2。rhBMP-2体外缓释：对照组rhBMP-2于150h基本全部释放；实验组rhBMP-2于350h缓释量约达99％，较对照组慢。动物实验：动物术后切口无感染，于4周行动自如。X线片示术后4周对照组骨缺损区材料清晰，实验组骨缺损区密度大部分接近宿主骨，材料模糊；8周对照组材料边缘较术后4周模糊，实验组骨缺损区密度已基本接近宿主骨。组织学观察，术后4周对照组可见少量成骨细胞和破骨细胞，实验组可见成熟骨组织和骨髓腔，新生骨逐渐取代材料；8周对照组可见大量成骨细胞和破骨细胞，少量新生骨并向材料内长入，实验组可见成熟骨小梁和骨髓组织。结论PCPC是rhBMP-2较理想的载体材料，复合后具有良好的诱导成骨作用，可作为一种新型复合人工骨修复骨缺损，具有良好的临床应用前景。     

负载rhBMP-2的CPC活性人工骨修复骨缺损的临床应用

目的 探讨负载rhBMP-2的CPC活性人工骨修复骨缺损的临床应用,评价其临床使用效果和安全性.方法 2006年6月-2007年9月,采用负载rhBMP-2的CPC(rhBMP-2/CPC组)和单纯CPC(对照组)修复骨缺损112例,骨缺损范围为1 cm×1 cm×1 cm～4 cm×3 cm×3 cm.其中对照组63例,男31例,女32例;年龄17～70岁,平均47.4岁.骨缺损部位:跟骨19例,胫骨平台20例,肱骨近端8例,桡骨远端9例,胸腰椎7例.rhBMP-2/CPC组49例,男31例,女18例;年龄16～68岁,平均45.6岁.骨缺损部位:跟骨11例,胫骨平台16例,肱骨近端7例,桡骨远端2例,胫骨远端2例,胸腰椎11例.术中采用负载rhBMP-2/CPC(2～5 g)或单纯CPC(2～50 g)填充骨缺损.结果 术后108例伤口Ⅰ期愈合;术后2周对照组1例及rhBMP-2/CPC组3例伤口有淡黄色清亮稀薄分泌物渗出,经换药及激素治疗后愈合.所有患者未见毒性反应,无皮疹或高热,肝肾功能、血、尿常规及C反应蛋白均正常.112例均获随访,随访时间12～24个月,平均13.2个月.随访期间未发生骨髓炎,无再骨折,无明显骨缺损修复后再塌陷,无钢板及螺钉松动、断裂等并发症,脊柱手术的椎体前缘无高度不足发生.两组术后3个月骨折均达骨性愈合,无延迟愈合或骨不连发生.患肢活动情况良好,屈伸功能达正常活动水平.结论 负载rhBMP-2的CPC活性人工骨修复骨缺损安全、有效,是一种理想的骨缺损修复材料.     

髓内打压植骨结合广泛多孔涂层长柄假体在股骨侧严重骨缺损（PaproskymA型）翻修术中的应用

目的 探讨股骨侧严重骨缺损（Paprosky ⅢA型）翻修中应用髓内打压植骨结合广泛多孔涂层长柄假体的临床疗效.方法 2006年3月～2010年9月,对38例（38髋）Paprosky ⅢA型股骨骨缺损患者行翻修重建,其中男24例,女14例,平均年龄62岁.翻修原因：骨溶解、无菌性松动29例,全髋关节置换术（THA）术后感染二期翻修6例,假体周围骨折3例（Vancouver B3型）.股骨侧干骺端骨缺损采用同种异体颗粒骨髓腔内打压植骨进行修复,股骨柄采用全涂层长柄假体（7～10英寸）.术后定期随访,髋关节功能评价采用Harris评分,影像学采用X线片及CT观察：假体柄有无松动下沉、股骨近端应力遮挡情况、植入的异体颗粒骨与宿主骨整合情况.结果 38例均获得随访,平均随访53.4个月（23～62个月）,Harris评分由术前平均42分（32～47分）,提高至末次随访时平均86分（69～95分）.无患者发生脱位、假体周围骨折.1例术后感染,行再次二期翻修;1例假体柄在术后6个月内下沉4.24 cm,再次翻修时选择更粗的假体柄,末次随访时假体柄稳定;其余所有患者假体柄均牢固固定.3例出现轻-中度应力遮挡.15例近端皮质骨密度及厚度有增加,厚度平均增加约1.8 mm（0.7～3.5 mm）,植入骨与宿主骨逐渐整合并增加了骨缺损区的骨质储备.结论严重骨缺损（Paprosky ⅢA型）的股骨翻修中,采用髓内颗粒骨打压植骨可以很好的修复股骨中上段骨缺损,重建股骨干骺端.依靠广泛多孔涂层长柄假体在远端的牢固压配固定,结合股骨干骺端髓内紧密打压植骨,使假体柄在股骨中上段及远端均能获得较好的初始稳定性,近期临床和影像学结果满意,远期疗效有待观察.     

自固化磷酸钙复合BMP及同种异体骨修复兔股骨大段骨缺损

[目的] 观察一种新型自固化磷酸钙（CPC）复合BMP与同种异体骨修复兔股骨节段性骨缺损的效果，为临床复合应用大段同种异体骨移植提供参考。[方法] 54只新西兰大白兔随机分成3组，于一侧股骨中上段造成2cm长皮质骨缺损模型，分别进行：A组复合BMP与CPC的新鲜冷冻同种异体骨移植；B组单纯新鲜冷冻同种异体骨移植；C组自体大段骨移植。移植骨均用直径3mm三棱髓内针固定。于术后4、8、12周，进行影像学、组织学检查，对比各组移植骨愈合过程与修复效果。[结果] CPC复合BMP大段同种异体骨移植早期骨修复效果优于单纯异体骨移植（P〈0．01），与自体骨移植修复效果相似，至12周3组均达骨性愈合，以A组及C组骨修复塑形较好。CPC复合BMP组骨痂量较多，分布于移植骨与宿主骨结合部及移植骨周围，形成皮质骨外骨桥，并较早在异体骨外表面形成破骨与成骨，异体骨内哈佛氏管扩大，衬垫细胞、成骨细胞、破骨细胞及血细胞较其它组多。CPC随着新骨的形成及改建塑形逐步缓慢降解。[结论] CPC复合BMP对大段同种异体骨移植的愈合及替代有增强和促进作用。     

多孔载因子CPC促进骨缺损愈合的实验研究

[目的]探讨磷酸钙骨水泥复合rhBMP-2/明胶微球复合材料在治疗骨缺损时的降解、成骨性能。[方法]制备携载rhBMP-2的明胶微球(GMs),与磷酸钙骨水泥(CPC)复合,制备出rhBMP-2/GMs/CPC复合人工骨。取30只新西兰大白兔,在前臂桡骨中段制造人工骨缺损,随机分成3组,分别植入rhBMP-2/GMs/CPC/复合物(A组)、GMs/CPC(B组)、rhBMP-2/CPC(C组),术后6、12周分别进行X线检测、骨密度测定,术后12周处死动物,分别行生物力学测定,脱钙切片、HE染色,不脱钙切片进行荧光显微镜下观察双标间距,计算平均矿化率。[结果]与GMs/CPC、rhBMP-2/CPC组比较,复合材料植入后不同时间点的材料降解及成骨均高于对照组。12周A组标本生物力学实验测定结果表明指标接近正常,与B、C组比较有统计学差异。骨密度12周、新骨矿化率提示有统计学差异。[结论]rhBMP-2/GMs/CPC微球系统复合材料在体内易降解,具有良好成骨活性,是良好的骨修复材料。     

BMP复合仿生人工骨填塞犬股骨假体周围髓腔骨缺损的实验研究

目的评估仿生人工骨（PLGA／TCP）材料作为BMP缓释系统载体材料修复犬假体涂层多孔钛周围骨缺损的可行性。方法给予8只犬进行右侧股骨头置换术，并充分扩髓，周围填充BMP复合的PLGA／TCP骨移植材料，应用X线拍片、组织和荧光观察、EDX及SEM检测、骨密度定量分析等方法，观察负重情况下该材料的实际效果。结果术后X线显示，未有出现透亮带、无假体下沉，未见骨质吸收；20周时骨与假体之间紧密接触，多孔钛内骨组织明显长入，以编织骨为主。植入的活性人工骨已经完全降解，骨小梁结构成熟；假体植入肢体与非手术肢体骨密度之比，显示在术后1个月假体植入侧的骨密度值有所降低，而后逐渐升高。结论多孔钛涂层有助于假体内骨与假体的固定，BMP复合PLGA／TCP作为新的骨移植材料应用于关节外科，有广泛的潜力和价值。     

携载rhBMP-2微球的新型可注射自凝固复合人工骨的制备及特性研究

[目的]制备一种具有良好降解性和成骨活性、可注射的自凝固新型骨修复材料。[方法]制备携载rhBMP-2的聚乳酸与聚乙醇酸共聚物（PLGA）微球，并将其与rhBMP-2／磷酸钙骨水泥（CPC）复合，制备出rhBMP-2／PLGA微球／CPC复合人工骨。探讨了材料的特性，包括形貌、固化时间、抗压强度及反映材料体外降解速度的指标一体外降解液Ca、P浓度变化，测定复合材料rhBMP乏的释药速度及体外诱导MSCs细胞成骨分化的能力。[结果]与单纯CPC-rhBMP-2相比，复合材料的固化时间少量增加，抗压强度下降明显。体外降解速度及体外释药明显提高，释放的rhBMP-2具有骨诱导活性。[结论]rhBMP-2／PLGA微球／磷酸钙骨水泥新型复合人工骨是具有良好应用前景的骨修复材料。     

rhBMP-2/卵磷脂复合材料修复犬长骨节段性骨缺损的实验研究

目的：观察rhBMP-2／卵磷脂复合材料修复犬长骨节段性骨缺损的能力，检验rhBMP-2的诱导成骨活性，方法：手术造成20mm桡骨中上段骨缺损，实验组植入rhBMP-2／卵磷脂的复合材料片，对照组植入单纯卵磷脂片，通过影像学、组织学观察及骨密度测定，评价rhBMP-2／卵磷脂复合材料修复犬长骨节段性骨缺损的效果，结果：影像学检查示实验组术12周骨痂桥接缺损，术后24周皮质骨连接；对照组无骨痂形成，组织学检查示实验组术后12周组织和肌组织充填，骨密度测定示术后12周骨痂密度达到正常值的76％，24周达正常值的85％，结论：rhBMP-2具有良好的诱导成骨活性，rhBMP-2／卵磷脂复合材料能够很好的修复犬桡骨20mm的骨缺损。     

自体成骨细胞--nBGC复合物修复犬胫骨骨缺损

目的：评价搭载自体骨细胞的纳米仿生材料在体内的组织反应性和骨修复作用。方法：4只犬的双侧胫骨各制作一直径l0mm的单侧皮质骨缺损，一侧骨缺损植人复合自体成骨细胞的仿生生物材料作为实验组，另一侧植人自固化磷酸钙(CPC)作为对照组。于术后8周取材，观察各组X线片、组织学、四环素荧光标记变化，比较骨缺损修复情况。结果：X线检查显示nBGC支架与周围骨组织很快融合，界限模糊；而对照组骨缺损界限仍清晰。nBGC支架内大量新骨组织形成，而在CPC植人组新生骨只沉积于植入物的表面，CPC周围有厚纤维组织条带包裹。结论：nBGC支架在体内既能降解又具有生物活性，能融入骨重塑过程，具有良好的组织反应性和骨修复作用，是一种皂好的组织工程骨支架材料．     

Histomorphometric description of allograft bone remodeling and union in a canine segmental femoral defect model: a comparison of rhBMP-2, cancellous bone graft, and absorbable collagen sponge.

The purpose of this study was to determine the effect of recombinant human bone morphogenetic protein type 2 (rhBMP-2) on the histomorphometry of femoral allograft-host bone union and allograft remodeling. A 6 cm mid-diaphyseal femoral defect was created and filled with an allograft stabilized with an interlocking nail in 21 dogs. Dogs were randomly divided into three equal groups and the allograft-host bone junctions and the mid-diaphyses of the allografts were treated with either an absorbable collagen sponge (ACS) loaded with rhBMP-2 (BMP group), an autogenous cancellous bone graft (CBG group), or ACS loaded with buffer solution (ACS group). All dogs received daily tetracycline until sacrifice at 24 weeks to label new bone formation. Histomorphometric analyses on sections of proximal and distal allograft-host bone junctions and the mid-diaphyseal portion of allografts were performed using fluorescent and regular light microscopy. Analyses of the host bone and junctions between allograft and host bone revealed significantly greater new bone formation and larger osteon radii in the BMP group compared to CBG and ACS groups and contralateral intact bone. Porosity in CBG and ACS groups was significantly higher than in the BMP group, which had similar values to intact bone. In transverse sections of allografts, the largest pore diameters were present in the CBG group. Based on all parameters measured, significantly higher bone turnover occurred in the outer cortical area of the allograft in all groups as compared to the inner cortical and mid-cortical areas. New bone formation and osteon radius/osteon width in allografts were similar for all three groups. Higher porosity and larger pore diameters in the CBG and ACS groups suggested higher bone resorption versus formation in these groups compared to the BMP group. The results of this study reveal more balanced allograft bone resorption and bone formation in the BMP group, with greater resorptive activity in the CBG and ACS groups. However, neither rhBMP-2 nor autogenous bone graft increased allograft incorporation when compared to the negative control (ACS group).     

Critically sized osteo-periosteal femoral defects: a dog model.

A 21-mm defect was created in 1 femoral diaphysis each of 15 dogs. Periosteum as well as a cylinder of bone was removed, and the defect was stabilized with a bone plate. Twelve of the defects were filled with an equal volume of autogenous cancellous bone harvested from the ipsilateral ilium. Three defects were left untreated. Cranial to caudal radiographs were taken postoperatively and every 4 weeks for 16 weeks. The radiographs were evaluated for healing using two ordinal scales. At 16 weeks, the dogs were euthanized and the femurs harvested for biomechanical testing and histologic evaluation. Both operated and contralateral not operated femurs were mechanically tested to failure in torsion, and load at failure and stiffness were calculated. All dogs tolerated the procedure well, and were using the operated limb within 1 or 2 days postoperatively. There were no complications noted during the 16 weeks of the study. Unfilled defects did not heal and became atrophic nonunions. The defects filled with autogenous cancellous bone healed in a consistent pattern of consolidation, incorporation, and remodeling, with uniform increases of both ordinal scales used. The femoral cortex opposite the bone plate demonstrated most mature remodeling, evident both radiographically as well as histologically. Unoperated femurs failed at 13.61 +/- 3.88 N-m and grafted femurs failed at 2.96 +/- 1.3 N-m, which was 23% of the measurement of the unoperated femur. Relative stiffness of the unoperated femurs was 5974 +/- 4316 N-m2/radian, and grafted femurs had a relative stiffness of 642 +/- 561 N-m2/radian, which was 10.4% of the measurement of unoperated femur. This model proved to be a critically sized defect, which when left unfilled resulted in an atrophic nonunion, and when filled with cancellous bone resulted in a consistent healing pattern.     

The effect of recombinant human bone morphogenetic protein-2 on femoral reconstruction with an intercalary allograft in a dog model.

This study compared the effect of augmentation of allograft host bone junctions with recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS), autogenous cancellous bone graft (CBG), and a collagen sponge alone in a canine intercalary femoral defect model repaired with a frozen allograft. Outcome assessment included serial radiographs, dual energy X-ray absorptiometry scans, and gait analyses, and mechanical testing and histology of post-mortem specimens. The distal junction healed more quickly and completely with rhBMP-2 than ACS alone based on qualitative radiography and histologic evaluations. The primary tissue in the unhealed gaps in the ACS group was fibrous connective tissue. The proximal allograft host bone junction had complete bone union in the three treatment groups. There was significantly greater new bone callus formation at both junctions with rhBMP-2 than with CBG or ACS alone that resulted in increased bone density around the allograft host bone junctions. All dogs shifted their weight from the treated leg to the contralateral pelvic limb immediately after surgery. Weight bearing forces were redistributed equally between the pelvic limbs at 12 weeks after surgery with rhBMP-2, at 16 weeks after surgery with CBG, and at 24 weeks after surgery with ACS alone. Bending and compressive stiffnesses of the whole treated femora were equal to the contralateral control femora in all treatment groups, whereas torsional rigidities of the whole treated femora for the CBG and ACS groups were significantly less than the control. Both the proximal and distal junctions the treated with rhBMP-2 had torsional stiffnesses and strengths equal to intact control bones. Ultimate failure torques of the proximal junctions of the CBG group and of both junctions of the ACS group were significantly less than the BMP-treated bones. Augmentation of the allograft host bone junctions with rhBMP-2 on an ACS gave results for all parameters measured that equaled or exceeded autogenous graft in this canine intercalary femoral defect model.     

中空多孔股骨柄假体骨长入方式的在体实验研究

目的 观察多孔中空人工股骨柄假体周围骨床骨质经界面长入金属空腔及其在腔室内成骨的特征,比较腔内复合骨诱导因子(rhBMP-2)与自身骨长入的成骨差异.方法 健康成年杂交犬18条,随机分3组,行单侧人工全髋关节置换术,术后摄X线片.所有股骨柄假体(CoCrMo合金)近1/2表面均为羟基磷灰石涂层.A组股骨侧植入实心假体,为对照组;B组在中空假体腔室内填塞股骨头颈及处理股骨近端髓腔时获得的松质骨;C组于腔室内填入复合5 mg rhBMP-2的胶原蛋白海绵.各组分别随机抽取2犬,于术后2、4、8个月处死取材,复查股骨近段X线片,不脱钙骨切片行界面和腔窒带假体组织学观察及骨形态计量学分析.结果 X线显示术后4个月C组假体中空部分周围骨床骨质密度明显较高.组织学观察C组近端假体一骨界面及腔窜内早期成骨速度明显快于A组和B组.假体植入后2、4个月时,C组的界面骨结合率明显高于另外两组(P<0.05),腔室内骨长入率也明显高于B组(P<0.05),但植入8个月后差异无统计学意义(P0.05).A、B两组之间的骨结合率差异无统计学意义(P0.05).结论 界面骨质町经孔洞长人中空金属假体腔室内,使假体与其周围骨床达成相对"一体化"结合.腔内复合rhBMP-2可有效促进早期假体一骨界面的骨结合及向假体腔室内的骨长入,为人类多孔中空股骨柄假体的研制和临床应用提供了可靠的实验依据.     

Human bone morphogenetic protein allografting for reconstruction of femoral nonunion

A composite inductive allograft consisting of an allogeneic, autolysed, antigen-free cortical bone carrier lyophilized with partially purified human bone morphogenetic protein was implanted in 30 consecutive femoral reconstructions that resulted from failure of fracture healing. There were 24 atrophic shortened femoral nonunions, four equal length femoral nonunions, and two femoral malunions. There were 10 men and 20 women with an average age of 47 years (range, 28-75 years). Allogeneic, autolysed antigen-free cortical bone was used as a structural alloimplant and as a delivery system for partially purified human bone morphogenetic protein. The composite implant of human bone morphogenetic protein/allogeneic, autolysed antigen-free cortical bone was used in conjunction with one-stage lengthening of the extremity, restoration of mechanical axis and rotational alignment. In 26 of 30 femurs, the human bone morphogenetic protein/allogeneic autolysed antigen-free cortical bone consisted of an allogeneic cortical bone implant incorporated into a one-stage lengthening of atrophic femoral nonunion. In four patients with equal length femoral nonunions, the human bone morphogenetic protein/allogeneic, autolysed antigen-free implant was placed as an medical femoral shaft onlay graft. Internal remodeling of the implant occurred within 8 to 12 weeks after implantation. Lengthening defects greater than 2 cm were supplemented with intercalary autogeneic bone graft. Twenty-four femurs healed at an average of 6 months at an average followup of 55 months. Four of six plate fatigue failures were salvaged with repeat plating. Two patients were lost to followup. The human bone morphogenetic protein/allogeneic, autolysed antigen-free bone allograft is an excellent structural and delivery system that induces host bone formation and implant remodeling allowing salvage of difficult femoral nonunions.     

可预防感染的组织工程骨在修复山羊大段骨缺损中的抗感染及成骨效果研究

 目的 构建可预防感染的组织工程骨并评估其在修复山羊大段骨缺损中的抗感染能力及成骨效果。方法 设计可控性缓释抗生素系统“纤维蛋白凝胶修饰的藻酸盐-万古霉素缓释微球”（FG-Vanco-AB）,以此为基础构建可预防感染的组织工程骨并进行检测,然后移植到山羊右侧股骨临界骨缺损的部位,对侧作为对照将组织工程骨（不含可控性缓释抗生素系统）移植到同样的临界骨缺损区。抗生素发挥抗菌作用的标准浓度为5 mg/ml,即对金黄色葡萄球菌的最低杀菌浓度,术后通过高效液相色谱法检测骨缺损区局部、周围及血液中万古霉素浓度,检测其缓释剂抗感染能力;组织学、CT、ECT检测骨愈合情况,以此来评价预防感染组织工程骨的成骨效果。结果 通过扫描电镜、激光共聚焦以及体内示踪等检测,种子细胞在体内及体外的存活情况与组织工程骨组类似;山羊股骨右侧局部、左侧局部及血液中持续超过杀菌浓度的时间分别为28 d、2 d和7 d。万古霉素在股骨中的浓度自移植部位向两侧逐渐递减。山羊双侧股骨术后第28天及56天ECT检查结果均提示无明显区别,CT及组织学检查证明在术后第14天、28天、112天,山羊双侧股骨缺损的修复是同步的,并且在第112天时均被新生骨组织覆盖。结论 成功构建抗感染的组织工程骨,FG-Vanco-AB在移植的部位可以发挥杀菌作用,并且不会影响组织的重建与修复。     

Critically Sized Osteo-Periosteal Femoral Defects: A Dog Model

A 21-mm defect was created in 1 femoral diaphysis each of 15 dogs. Periosteum as well as a cylinder of bone was removed, and the defect was stabilized with a bone plate. Twelve of the defects were filled with an equal volume of autogenous cancellous bone harvested from the ipsilateral ilium. Three defects were left untreated. Cranial to caudal radiographs were taken postoperatively and every 4 weeks for 16 weeks. The radiographs were evaluated for healing using two ordinal scales. At 16 weeks, the dogs were euthanized and the femurs harvested for biomechanical testing and histologic evaluation. Both operated and contralateral not operated femurs were mechanically tested to failure in torsion, and load at failure and stiffness were calculated. All dogs tolerated the procedure well, and were using the operated limb within 1 or 2 days postoperatively. There were no complications noted during the 16 weeks of the study. Unfilled defects did not heal and became atrophic nonunions. The defects filled with autogenous cancellous bone healed in a consistent pattern of consolidation, incorporation, and remodeling, with uniform increases of both ordinal scales used. The femoral cortex opposite the bone plate demonstrated most mature remodeling, evident both radiographically as well as histologically. Unoperated femurs failed at 13.61 3.88 N-m and grafted femurs failed at 2.96 1.3 N-m, which was 23% of the measurement of the unoperated femur. Relative stiffness of the unoperated femurs was 5974 4316 N-m2/radian, and grafted femurs had a relative stiffness of 642 561 N-m2/radian, which was 10.4% of the measurement of unoperated femur. This model proved to be a critically sized defect, which when left unfilled resulted in an atrophic nonunion, and when filled with cancellous bone resulted in a consistent healing pattern.     

Effects of rhBMP-2 on cortical strut allograft healing to the femur in revision total hip arthroplasties: an experimental study

We have studied the effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) on cortical strut allograft healing and remodelling in revision hip arthroplasty. Thirty adult New Zealand rabbits underwent bilateral onlay allograft strut procedures to the femur using wires. The left femur (experimental side) received the rhBMP-2 device (1.0-mg rhBMP-2/gelatin composites) interposed between the allograft and host bone, while the right side was grafted with an allograft strut as the control. The femurs and implants were retrieved at 4, 6, and 8 weeks postoperatively. The healing of cortical strut grafts to the femur was enhanced dramatically by the addition of the rhBMP-2 device in radiographic examination, contact radiographic examination, non-decalcification sections, fluorescence tag, and computer-aided image analysis. The remodelling of cortical strut allograft was also accelerated. The new bone formation ratio and radiographic scores of the experimental side were also much higher than the control side at all times. Strut healing with the rhBMP-2 device at 4 weeks postoperatively was superior to the healing in control sides at 8 weeks. Our findings showed that the rhBMP-2 device improved and accelerated the course of cortical strut allograft healing and remodelling with host bone.     

局部应用CPC/rhBMP-2复合材料对骨质疏松大鼠骨折愈合的影响

目的研究磷酸钙骨水泥（Calcium Phosphate Cement，CPC）与重组人骨形态发生蛋白-2（Recombinant Human Bone Morphogenefic Protein-2，rhBMP-2）复合材料对骨质疏松大鼠骨折愈合的影响。方法取4月龄雌性清洁大鼠106只，随机分成实验组96只，对照组10只。实验组行双侧卵巢切除术，对照组行假手术，术后行双能X线骨扫描确定骨质疏松动物模型形成。然后将实验组96只大鼠制作右侧股骨远端松质骨骨折，将上述动物随机分成3组，每组32只：（1）克氏针组，从髁间窝穿入直径1mm克氏针固定；（2）CPC组，将CPC从12号针头注入骨髓腔，手法固定至骨水泥凝固；（3）CPC-BMP组，将CPC与rhBMP-2复合材料用12号针头注入骨髓腔，手法固定至骨水泥凝固。术后第2、4、6、8wk三组各取8只动物处死，取手术侧股骨远端标本行压缩实验。结果在上述4个时间点，CPC-BMP组的骨折段最大载荷较克氏针组及CPC组增高（P〈0．05）；第2周CPC组骨折段最大载荷较克氏针组增高（P〈0．05）。结论（1）局部注射CPC-BMP复合材料可以促进骨质疏松大鼠骨折的愈合，提高骨折愈合后的强度；（2）CPC局部应用可以对骨折起到即时固定作用。