股骨头内支撑器/重组人骨形态发生蛋白/自体松质骨对犬股骨头坏死软骨下骨缺损的修复

目的探索应用新材料、新方法修复股骨头坏死骨缺损重建股骨头力学性能的新方法。方法活门法(trapdoor)建立犬股骨头骨缺损模型。通过活门A组植入股骨头内支撑器/重组人骨形态发生蛋白(rhBMP)2/自体松质骨;B组植入重组人骨形态发生蛋白(rhBMP)2/自体松质骨;C组植入自体松质骨。通过组织学、影象学、生物力学观察评价对股骨头骨缺损的修复以及重建股骨头力学性能的效果。结果各组均未出现关节脱位、关节间隙正常。A组缺损区修复,无关节软骨塌陷,内支撑器与周围骨组织融合;B组,骨缺损区修复,但骨密度低于周围骨组织;C组,仅缺损区周围少量低密度骨形成。A组组织学无软骨塌陷,内支撑器周围新生骨组织包绕,与周围骨组织融合;B组2例软骨塌陷(1.2mm,1.5mm),活门区软骨色泽近与正常,缺损区由新生骨组织填充;C组,活门区软骨塌陷(1.8～5.2mm),色泽苍白,质软易碎,骨缺损区边缘少量新生骨组织,骨小梁纤细稀疏。A组抗压强度为(289.46±23.05)MPa,B组抗压强度为(128.34±6.23)MPa,C组抗压强度(119.54±64.75)MPa,A明显强于B、C两组,且差异有统计学意义(P<0.05)。结论应用股骨头内支撑器/rhBMP2/自体松质骨修复股骨头软骨下骨缺损可以加快修复速度,并且恢复重建股骨头力学强度,有效的防止股骨头关节软骨的塌陷。     

髋臼后壁重建模型的建立及其生物力学分析

目的 :在尸体上模拟髋臼后壁缺损的模型,评价不同后壁重建方法对髋臼与股骨头接触特性的影响。方法:获取6具成人尸体的骨盆股骨标本,采用随机数字表法分为A组和B组。均采用后壁截骨法建立髋臼后壁60°弧1/2缺损的模型;两侧缺损区分别选用不同的重建方法。其中,A组凿取髂前上棘后方的自体髂骨以制作解剖性自体髂骨;B组于髂后上棘前方凿取髂骨块。将髋关节置于直立位、屈曲位及后伸位,从10~250 N分级加载,使载荷直接作用于髋臼后壁上。采用压敏片检测不同状态下形变位移、载荷、头臼接触面积及接触应力。结果:在不同的髋关节状态下,A组在一定载荷下的形变位移略大于B组,但差异无统计学意义(P0.05)。与完整髋臼相比,后壁重建使头臼接触面积有所减少;在250 N载荷下,A组(解剖重建组)头臼接触面积与B组(普通重建组)比较的差异无统计学意义(P0.05);其平均接触应力小于B组(P0.05),说明A组应力集中小于B组。结论:后壁截骨法建立的尸体髋臼后壁缺损模型可有效模拟临床实际;解剖重建使后壁头臼接触面积及应力分布恢复比较理想,接近正常髋关节,避免了局部应力集中。     

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。     

应用骨形态发生蛋白(BMP)修复关节软骨缺损的实验研究

目的探讨关节软骨全层缺损应用骨形态发生蛋白修复的效果。方法于2004年5月至2005年12月,30只新西兰种成年兔随机分为A,B,C三组,每只兔子左膝股骨髁间凹做一大小为4mm×5mm×2.5mm的全层关节软骨缺损。A,B组缺损内分别填充骨形态发生蛋白/纤维蛋白胶(BMP/FG)及FG,C组为空白。术后28周对缺损修复情况行大体形态、组织学和电镜观察。结果BMP/FG组,缺损组织以透明软骨修复,接近正常组织,而FG组和空白组则以纤维组织修复为主。结论BMP/FG能较好的完成关节骨软骨全层缺损的修复,并随着时间的延长修复的软骨越接近正常软骨,但修复软骨缺损的组织与邻近正常软骨组织连接性仍不是十分理想。     

BMSCs种植双相复合支架修复兔关节软骨及软骨下骨缺损

目的关节软骨的病变常伴有软骨下骨缺损,其修复重建一直是骨科难题。探讨BMSCs-双相支架复合物修复骨软骨缺损的可行性,比较其与植入单纯双相支架及动物自身修复效果的差别具有重要意义。方法以聚乳酸/聚羟基乙酸共聚物(poly-lactic-co-glycolic acid,PLGA)、羟基磷灰石(hydroxyapatite,HA)为原料制备由软骨相和骨相构成的三维支架,提取天然Ⅰ型胶原(collagen typeⅠ,ColⅠ)涂于表面制成PLGA-HA-ColⅠ双相支架。取新西兰乳兔骨髓分离培养获得的第2代BMSCs,以1×106个/mL接种于双相支架,扫描电镜观察支架结构和细胞分布。取30只6月龄新西兰大白兔,建立股骨远端关节面骨软骨缺损模型,随机均分为3组,A、B组分别于缺损区植入单纯双相支架和BMSCs-双相支架复合物,C组作为空白对照组未植入支架材料。于术后1、3、6、9个月取材行大体及组织学观察,术后9个月对A、B组标本行大体评分比较、micro CT扫描定量分析及免疫组织化学染色观察。结果扫描电镜示双相支架孔隙连通性好,软骨相和骨相孔径不同,BMSCs在双相支架内生长良好。大体观察示术后9个月内A组关节表面逐渐形成类软骨样组织,部分出现塌陷或不规则缺损;B组关节面无塌陷或碎裂,新生组织质地更接近正常组织;C组缺损一直存在。大体评分显示3组修复效果比较差异均有统计学意义(P0.001),B组优于A组,C组最差。micro CT扫描示A、B组软骨下骨得到良好的修复重建,定量分析示B组骨组织体积分数、结构模型指数及骨小梁数目均高于A组,但差异无统计学意义(P0.05)。组织学观察示术后1个月A、B组缺损区存在炎性反应;术后3个月新生组织长入;术后6个月支架完全降解,新生组织在植入物及缺损边缘爬行生长;术后9个月形成大量胶原纤维,表面多为纤维软骨。C组观察期内缺损持续存在。术后9个月免疫组织化学染色示A、B组标本缺损区ColⅡ染色呈弱阳性,ColⅠ染色阳性。结论PLGA-HA-ColⅠ双相支架具备较适宜的一体化修复骨软骨缺损的物理特性,接种BMSCs后整体修复效果更好。     

软骨PLGA-Ⅱ型胶原支架复合体修复兔膝关节骨软骨损伤

目的探讨骨髓基质干细胞(BMSCs)诱导的软骨细胞与聚乙醇酸-乳酸共聚物(PLGA)-Ⅱ型胶原支架通过管帽结构复合构建组织工程软骨复合体修复兔膝关节骨软骨损伤的效果及各界面耦合情况。方法BMSCs经软骨诱导液诱导成软骨细胞后接种于PLGA-Ⅱ型胶原支架的底层,支架表层戴管帽。将该细胞-支架复合物置入软骨条件培养液中培养2周,扫描电镜观察。将45只新西兰大白兔随机分为A、B、C 3组,每组15只,并于股骨髁处造模。分别于缺损处植入戴管帽结构复合的软骨支架复合体(A组)、PLGA-Ⅱ型胶原支架(B组)、不植入任何材料(C组)。于第4周和第12周取材行大体观察和组织学分析。结果 A组和B组缺损处均有软骨生成;C组缺损明显,只有纤维组织生长。A组软骨缺损部分软骨细胞修复,成骨区部分骨样细胞修复;两者耦合处犬牙交错,修复缺损程度及成骨区和成软骨区界面耦合情况明显优于B、C组。软骨组织学评分A组优于B、C组(P0.05)。结论 BMSCs诱导分化成的软骨细胞与PLGA-Ⅱ型胶原支架经过管帽结构构建成的软骨PLGA-Ⅱ型胶原支架复合体可有效修复兔膝关节骨软骨损伤,新生软骨、骨与宿主软骨、骨及新生软骨与软骨下骨各界面耦合良好。     

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.     

动物源性骨软骨支架修复兔膝关节复合缺损

目的探讨软骨细胞-动物源性骨软骨支架复合体修复兔膝关节骨软骨复合缺损的可行性和影响因素。方法将改良贴壁离心法获取的骨髓间充质干细胞（bone marrowm esenchymal stem cells,BMSCs）/诱导分化的软骨细胞共培养后与经深低温冷冻、脱脂、脱钙、真空冷冻干燥和辐照消毒的动物源性骨软骨支架复合,构建共培养细胞＋软骨-骨一体化复合支架。27只新西兰大白兔随机分为实验组（A组）、对照组（B组）和空白组（C组）,每组9只。于兔股骨髁间窝处钻一深6mm的骨软骨复合缺损,A组植入共培养细胞＋骨软骨复合支架,B组植入骨软骨复合支架,C组不植入任何支架材料和细胞,分别于术后4周、8周和12周取材,行大体观察、苏木精—伊红染色和甲苯胺蓝染色,并对各标本的软骨切片进行组织学评分。结果随着时间的延长,A组大体观察见复合缺损区已完全修复,局部无凹陷,新生组织和周围组织融合;B组新生组织仍不能完全填充缺损;C组缺损区仍明显。苏木精—伊红染色和甲苯胺蓝染色见A组软骨缺损区由新生的透明软骨样组织修复,细胞呈柱状排列,极性好,软骨陷窝明显,骨缺损区由骨样组织修复,新生软骨和软骨下骨以及宿主骨界面耦合良好;B组新生软骨细胞无软骨陷窝,排列混乱,各界面藕合欠理想;C组可见陈旧性肉芽组织生长并突出于缺损区表面。甲苯胺蓝染色阳性率和组织学评分结果表明,A组与B、C两组之间的差异具有统计学意义（P〈0.05）。结论 BMSCs/诱导分化的软骨细胞共培养细胞复合动物源性骨软骨支架对兔膝关节软骨和软骨下骨的复合缺损具有修复作用。     

新鲜同种异体骨软骨移植修复软骨缺损

目的联合应用新鲜同种异体骨软骨移植,和局部注射碱性成纤维细胞生长因子(basic fibroblast growthfactor,bFGF),探讨能否促进关节软骨缺损区新生软骨的形成,提高软骨缺损修复的成功率。方法48只青紫兰兔,96个实验关节,随机分为A、B、C、D组。无菌条件下制作骨软骨缺损模型。在A组缺损区单纯植入新鲜的同种异体骨软骨,B组单纯局部注射重组人bFGF,C组局部注射bFGF后同时植入新鲜的同种异体骨软骨,D组用作空白对照。术后第4、8、12周作大体观察、X线摄片、组织学检查及免疫组化检查。结果移植加注射bFGF组促进软骨缺损修复的效果均好于其他组,图像分析仪进行软骨细胞记数有显著差异(P<0.05),有统计学意义。修复软骨型胶原免疫组化染色强阳性。结论采用新鲜的同种异体骨软骨移植及联合应用碱性成纤维细胞生长因子,二者能起交互作用,促进了新生软骨的形成。     

无细胞支架修复家兔关节软骨缺损的实验研究

[目的]探讨无细胞的软骨修复支架对动物模型关节软骨损伤的修复效果,及其临床应用的可能性和优势。[方法]成年新西兰大白兔构建软骨缺损动物模型。A组为空白对照组,仅做缺损手术;B组为无细胞支架组,植入不含细胞的支架;C组为负载细胞的支架组,植入负载种子细胞的支架。术后6、12周取材,体视显微镜观察、HE染色和甲苯胺蓝染色观察。术后12周的标本参考国际软骨修复协会组织学评分(International Cartilage Repair Society Histological Scoring,ICRS)标准评分,并对修复后新生组织力学性能进行检测。[结果]体视显微镜观察显示:A组,缺损周边仅有少量修复。B、C组,修复平面略低于周边正常组织,关节面较光滑,修复组织与周围软骨整合较好。HE染色与甲苯胺蓝染色显示:A组,缺损区域主要为纤维组织。B、C组,缺损区域中有大量软骨样组织生成。B、C两组评分的差别无统计学意义(P0.05),但两组的评分均显著高于A组(P0.05)。生物力学检测结果显示,正常软骨组织压缩模量为(0.61±0.06)MPa,A、B、C三组压缩模量分别为(0.08±0.05)MPa、(0.16±0.06)MPa、(0.22±0.06)MPa。与A组相比,B组与C组的压缩模量均有显著改善,但与正常软骨组织相比仍有明显降低(P0.05)。[结论]单纯支架植入与支架负载细胞共同植入,对关节软骨的修复效果无显著性差异,提示负载细胞并未对软骨修复效果有明显的改善。因此,本研究基于无需细胞种植的软骨再生技术理念,使用无细胞支架修复关节软骨损伤/缺损,有可能作为一种更为简便的再生医学方法在软骨损伤、缺损的治疗中发挥重要作用。     

Sizable Scaffold‐Free Tissue‐Engineered Articular Cartilage Construct for Cartilage Defect Repair

This study introduces an implantable scaffold‐free cartilage tissue construct (SF) that is composed of chondrocytes and their self‐produced extracellular matrix (ECM). Chondrocytes were grown in vitro for up to 5 weeks and subjected to various assays at different time points (1, 7, 21, and 35 days). For in vivo implantation, full‐thickness defects (n = 5) were manually created on the trochlear groove of the both knees of rabbits (16‐week old) and 3 week‐cultured SF construct was implanted as an allograft for a month. The left knee defects were implanted with 1, 7, and 21 days in vitro cultured scaffold‐free engineered cartilages. (group 2, 3, and 4, respectively). The maturity of the engineered cartilages was evaluated by histological, chemical and mechanical assays. The repair of damaged cartilages was also evaluated by gross images and histological observations at 4, 8, and 12 weeks postsurgery. Although defect of groups 1, 2, and 3 were repaired with fibrocartilage tissues, group 4 (21 days) showed hyaline cartilage in the histological observation. In particular, mature matrix and columnar organization of chondrocytes and highly expressed type II collagen were observed only in 21 days in vitro cultured SF cartilage (group 4) at 12 weeks. As a conclusion, cartilage repair with maturation was recapitulated when implanted the 21 day in vitro cultured scaffold‐free engineered cartilage. When implanting tissue‐engineered cartilage, the maturity of the cartilage tissue along with the cultivation period can affect the cartilage repair.     

骨髓基质细胞与几丁质复合移植修复关节软骨缺损的实验研究

目的 :探讨骨髓基质细胞 (MSCs)与几丁质复合移植对关节软骨缺损的修复效果。方法 :分离兔骨髓基质细胞并体外培养增殖后 ,与几丁质无纺网复合培养 ;制作兔膝关节软骨全层缺损模型 ,分别用MSCs 几丁质复合物移植、单纯几丁质移植及空白对照组 ,术后第 4、 8、 12、 16周处死动物 ,大体观察并做组织形态学观察。结果 :几丁质 MSCs组术后 16周关节软骨缺损其修复组织表面与正常软骨完全相同 ,软骨及软骨下骨修复 ;单纯几丁质移植组为透明软骨修复 ,表面不平整 ,细胞排列不规则 ,软骨下骨基本修复 ;空白对照组术后各期均为纤维组织修复。结论 :MSCs与几丁质复合移植对关节软骨缺损有较好的修复效果     

Use of a guanidine extract of demineralized bone in the treatment of osteochondral defects of articular cartilage

In order to evaluate the ability of a guanidine extract of demineralized bone to repair osteochondral defects in articular cartilage, plugs made of this extract were implanted into defects in rabbit knees. The repair tissue was examined macroscopically, histologically, and immunohistochemically at 4, 8, 12 and 30 weeks. Controls (defects that were left empty) showed no cartilage formation. Four weeks after implantation of a guanidine extract plug, histological examination showed a nonhomogeneous metachromatically stained region extending from the surface of the repair tissue down to cancellous bone. This region also was labeled by an anti-type-II collagen antibody, indicating that cartilage-like tissue had been induced. At 8 weeks, the newly formed cartilage in the subchondral and cancellous bone had been partially replaced by bone. At 12 weeks, the thickness of the newly formed cartilage layer had decreased, and most of the newly formed cartilage in the subchondral and cancellous bone had been replaced by bone. In addition, a tidemark was observed. At 30 weeks, the repair tissue was a mixture of cartilage and fibrocartilage, and there was severe degeneration of the cartilage surrounding the repaired defects. These findings indicate that osteochondral defects of articular cartilage can be partially repaired by the implantation of a guanidine extract and that the newly formed cartilage-like tissue is not permanent.     

异体软骨细胞复合Pluronic修复关节软骨缺损

目的 探讨运用同种异体软骨细胞复合Pluronic修复关节软骨缺损的可行性，并应用^3H—TdR放射自显影方法鉴别软骨缺损修复的细胞来源。方法 取同种异体软骨细胞体外培养至第2代，用^3H—TdR标记后复合Pluronic植入兔关节软骨缺损区作为实验组，并采用单纯Pluronic植入作为材料对照组，不作任何处理组为空白对照组，分别于4、8及16周取材，观察其修复效果，并应用放射自显影方法鉴别修复组织的细胞来源。结果 实验组术后8周，缺损表面可见新生软骨形成，术后16周缺损完全修复，表面光滑，与周围界限模糊，放射自显影证实所修复组织的细胞来源于植入细胞。材料对照组及空白对照组缺损均未见明显修复。结论 ①同种异体软骨细胞复合Pluronic修复关节软骨缺损是可行的；②^3H—TdR标记细胞可作为鉴别细胞来源的一种简便可行的方法。     

培养软骨移植修复关节软骨缺损的实验研究

目的：为探讨一种新的关节软骨缺损修复方法。方法：将体外培养２周形成软骨样组织,移植修复兔关节软骨全层缺损。于移植术后２、４、８周分别行功能评价、大体形态及组织学检查。结果：全部实验兔于术后２周内恢复正常活动。２周时移植修复组织由非成熟透明软骨组成。４周时部分移植组出现成熟透明软骨。８周时移植组关节软骨缺损全部由成熟透明软骨充填修复,修复组织与邻近关节软骨融合。培养软骨移植修复关节软骨全层缺损明显优于自身修复（Ｐ＜００１）。结论：本实验提示使用具有高有丝分裂率的软骨细胞,经离心管培养形成骺软骨样组织,植入关节软骨全层缺损后,软骨细胞生长良好,逐渐成熟和转化,能发挥良好的修复作用。     

The osteochondral dilemma: review of current management and future trends

The management of articular cartilage defects remains challenging and controversial. Hyaline cartilage has limited capacity for self‐repair and post‐injury cartilage is predominantly replaced by fibrocartilage through healing from the subchondral bone. Fibrocartilage lacks the key properties that characterize hyaline cartilage such as capacity for compression, hydrodynamic permeability and smoothness of the articular surface. Many reports relate compromised function associated with repaired cartilage and loss of function of the articular surface. Novel methods have been proposed with the key aim to regenerate hyaline cartilage for repair of osteochondral defects. Over the past decade, with many exciting developments in tissue engineering and regenerative cell‐based technologies, we are now able to consider new combinatorial approaches to overcome the problems associated with osteochondral injuries and damage. In this review, the currently accepted surgical approaches are reviewed and considered; debridement, marrow stimulation, whole tissue transplantation and cellular repair. More recent products, which employ tissue engineering approaches to enhance the traditional methods of repair, are discussed. Future trends must not only focus on recreating the composition of articular cartilage, but more importantly recapitulate the nano‐structure of articular cartilage to improve the functional strength and integration of repair tissue.     

Surgical repair of cartilage defects of the patella

The structure and biomechanical forces on the patellar joint challenges researchers to define an ideal method for resurfacing the patellar cartilage. The articular surface of the patella presents variability between individuals, and has various minor articulations that bear partial or total compressive, shear, and combined forces during movement. Surgical techniques for the repair of patellar cartilage defects have evolved from cumulative advances in basic science and technology. Such surgeries include the techniques that promote either fibrocartilage formation or hyalinelike cartilage formation. Techniques promoting the formation of fibrocartilage yield short-term solutions because fibrocartilage lacks the durability and the mechanical properties of articular hyaline cartilage. Currently, there is no ideal method for the repair of patellar cartilage defects; all methods are considered experimental. Additional controlled and randomized clinical studies with large series of patients and long-term followup are required.     

同种异体软骨细胞移植术后关节软骨蛋白多糖的测定

目的 应用Pluronic F-127负载同种异体软骨细胞移植修复兔全厚关节软骨损伤,对于新生的修复组织进行基质蛋白多糖含量测定,以探讨此方法修复全厚关节软骨损伤的可行性.方法 取3个月龄新西兰大白兔关节软骨细胞体外培养扩增,与20%Plurortic F-127凝胶混合.选27只健康同种成年大白兔,人为造成双侧膝关节软骨缺损.实验组软骨缺损处植入培养的软骨细胞/Pluronic F-127混合物,对照组缺损处单纯注入Pluronic F-127凝胶和空白对照.然后,对修复组织进行大体观察及蛋白多糖含量测定.结果 移植的软骨细胞-载体复合物中的软骨细胞能良好地生长,12周时再生组织与周围正常软骨组织外观相似,界限模糊.实验组与对照组各时期蛋白多糖含量均有非常显著性差异,实验组不同时期的蛋白多糖含量之间均有显著性差异,实验组12周时蛋白多糖含量与正常软骨组织无显著性差异.结论 Pluronic F-127负载同种异体软骨细胞移植是治疗关节软骨缺损的有效方法.     

Porous bioactive glass matrix in reconstruction of articular osteochondral defects.

BACKGROUND AND AIMS: This study was carried out to investigate the use of porous bioactive glass implants in promotion of articular cartilage and subchondral bone repair in large osteochondral joint defects. MATERIAL AND METHODS: Two conical osteochondral defects (top diameter 3.0-3.2 mm) were drilled into the patellar grooves of the distal femurs in the rabbit. The defects, extending (approximately 6-7 mm) from the surface of the articular cartilage to the subchondral marrow space, were reconstructed with size-matched porous conical implants made of sintered bioactive glass microspheres (microsphere diameter 250-300 microm, structural implant compression strength 20-25 MPa) using press-fit technique. The implant surface was smoothened to the level of the surrounding articular cartilage. One of the two defects in each femur was left empty to heal naturally and to serve as the control. At 8 weeks, the defect healing was analyzed with use of a semiquantitative histological grading system, histomorphometry of subchondral bone repair, back-scattered electron imaging of scanning electron microscopy (BEI-SEM), and a microindentation test for characterization for the stiffness properties of the cartilage repair tissue. RESULTS: The porous structure of the bioactive glass implants, extending from the articular defect of the patellar groove into the posterior cortex of the femur, was extensively filled by new bone. Cartilage repair varied from near-complete healing by hyaline cartilage to incomplete healing predominantly by fibrocartilage or fibrous tissue. There were, however, no statistical differences in the histological scores of repair between the glass-filled and control defects, although the sum of the averages of each category was lowest for the bioactive glass filled defects. The indentation stiffness values of all the defects were also significantly lower than that of normal cartilage on the patellar groove. CONCLUSIONS: Porous textures made by sintering bioactive glass microspheres may expand the opportunities in reconstruction of deep osteochondral defects of weight-bearing joints. The implants act mechanically as a supporting scaffold and facilitate the penetration of stromal bone marrow cells and their chondrogenic and osteogenic differentiation. Ionic properties of the bioactive glasses make the substances highly potential even as delivery systems for adjunct growth factor therapy.