关节软骨的修复与修复失败

文题释义： 自体软骨细胞移植：对于3.5-10 cm2的软骨缺损或多个缺损来说,自体软骨细胞移植是一种有效的软骨修复措施,取少量患者自体软骨于体外培养软骨细胞,并增殖到一定数量后植入软骨缺损处,从而达到修复缺损的目的。 基质诱导的自体软骨细胞移植：把经培养增殖后的软骨细胞接种到Ⅰ/Ⅲ型双层胶原膜上,继续培养数日,细胞与支架结合紧密之后,使用生物蛋白胶粘贴到关节软骨缺损病灶底部。术后,软骨细胞从胶原膜上游离并穿过生物胶,迁徙到软骨缺损的基底部。胶原膜和生物胶逐步降解并被吸收。接种的软骨细胞在局部生长、繁殖,并分泌基质,形成新的软骨组织修复缺损。背景：由于关节软骨具有复杂的生物学特性和高度的耐用性,自然退变或创伤引起的缺损都可能导致其结构和功能上不可逆的损害,因此关节软骨损伤后的修复治疗是临床上急需解决的问题。 目的：报告关节软骨修复技术失败最常见的危险因素及其发生率,分析影响选择特定手术治疗方法来处理软骨修复失败最重要的因素。 方法：以“articular cartilage, repair, clinic/clinical failure, surgery”为检索词,检索 PubMed和MEDLINE数据库,时限为2007至2019年,语言限制为英文。初检得到文献约343篇,根据纳入排出标准筛选,共纳入38篇文章进行分析。 结果与结论：①微骨折术和软骨镶嵌成形术在关节软骨修复后的前期和中期显示出不可忽视的失败率,而使用自体软骨细胞移植和异体骨软骨移植修复关节软骨的效果更好。②对于软骨修复失败的治疗：在以往软骨修复失败的患者中应用异体骨软骨移植可能是一个安全的选择,但对于失败的异体骨软骨移植的修复则有更高的失败率;而既往自体软骨细胞移植或基质诱导的自体软骨细胞移植失败的患者,经进一步的自体软骨细胞移植或基质诱导的自体软骨细胞移植治疗后,其治疗效果是可以接受的。此外,有软骨下骨髓刺激病史的患者,自体软骨细胞移植的失败率更高。③软骨修复失败的处理取决于手术治疗失败的类型以及软骨缺损的面积、部位的不同,异体骨软骨移植是治疗软骨下骨髓刺激患者软骨修复失败的最可靠的方法,而自体软骨细胞移植或基质诱导的自体软骨细胞移植在既往软骨修复失败的患者中显示出可以接受的治疗效果,在处理软骨修复失败的患者时,应该特别注意软骨下骨质的情况。ORCID: 0000-0002-3907-9145(张宇) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

用组织工程学方法探讨兔佐剂性关节炎关节软骨修复的实验研究

目的探讨海藻酸盐支架超微结构及软骨形态变化与组织工程修复佐剂性关节炎软骨缺损的关系,为临床应用组织工程方法治疗类风湿性关节炎(rheumatoid arthritis,RA)提供一定的实验依据。方法将24只新西兰兔随机均分为假手术对照组,关节炎模型组和软骨细胞-海藻酸钙支架复合物治疗组。对模型组和治疗组膝关节处注射0.5 m L完全弗氏佐剂诱导关节炎,假手术组注射等量生理盐水。抽取治疗组骨髓5 m L,Percoll密度梯度分离出自体骨髓间充质干细胞,体外培养纯化,并诱导分化成软骨细胞。与海藻酸钙支架混合培养,对支架进行扫描电镜观察,并将混合物回注相应关节腔内治疗1个月。对各组兔膝关节进行组织学评分检测软骨缺损修复结果。结果海藻酸盐支架电镜扫描显示支架具有一定的孔隙,有利于营养物质的进入,便于细胞的增殖分化。软骨组织评分结果显示软骨纤维化减轻,关节腔内积液消失,软骨缺损得到一定修复。结论软骨组织评分显示海藻酸钙复合工程化软骨细胞对兔佐剂性关节炎软骨缺损有一定的修复作用,其机制可能与支架有利于软骨细胞生长发育有关。     

膝关节软骨损伤的治疗进展

[摘要]膝关节具有多样且复杂的运动形式,是人体承重最大的关节,最易导致关节软骨损伤。由于其再生修复的能力很弱,故其损伤后很难自身修复,进而导致骨关节炎的发生。膝关节软骨损伤后目前主要有以下的手术治疗方式：①自体骨软骨移植技术（马赛克移植技术）;②同种异体骨软骨移植技术;③自体软骨细胞移植; ④合成或生物支架植入（组织工程技术）;⑤微骨折技术;⑥粉碎软骨修复技术;⑦生物制剂辅助治疗。通过选择性运用上述治疗可以在短期内改善临床症状,延迟或者避免行关节置换手术,本文将对其一一进行综述。     

微骨折技术与骨软骨移植治疗关节软骨缺损

背景：关节镜下微骨折治疗与骨软骨移植是关节软骨缺损主要的治疗方法之一,具有广阔的应用前景。 目的：探讨关节镜下微骨折治疗与自体和同种异体骨软骨移植治疗膝骨关节炎合并关节软骨缺损的效果。 方法：应用关节镜下微骨折治疗清理术结合软骨缺损区微骨折术治疗膝骨关节炎的临床疗效、临床症状及Tegner运动评级判定疗效并随访观察3-24个月。自体骨软骨移植治疗关节软骨缺损的患者进行观察随访,通过评价移植后关节活动度、临床症状的改善、关节影像学检查等评估自体骨软骨移植治疗的效果。并对同种异体骨软骨移植治疗关节软骨缺损进行动物实验研究,通过对移植部位的大体观察、组织学观察以及免疫组织化学染色观察,评估同种异体骨软骨移植治疗的效果。 结果与结论：关节软骨缺损应用关节镜下微骨折治疗后的患者,关节清理术结合软骨缺损区微骨折术总有效率89.7%。关节软骨缺损应用自体骨软骨移植治疗后的患者,关节疼痛、肿胀的症状改善,关节活动度正常,偶有关节静息痛或活动后轻微疼痛,影像学检查见移植骨软骨位置良好,修复愈合良好。关节软骨缺损应用同种异体骨软骨移植治疗后的实验动物,关节活动度正常,移植关节面光整,关节软骨被透明软骨覆盖,细胞有序排列,软骨基质分泌,修复软骨Ⅱ型胶原免疫组织化学染色强阳性。     

不同种类组织工程化细胞移植修复关节软骨的损伤

背景:单纯药物治疗不能有效促进关节软骨缺损的愈合;自体软骨来源有限,软骨移植手术也相应受到限制。目的:分析关节软骨损伤类型及局部微环境的改变,总结近年来国内外组织工程种子细胞移植研究相关进展以及细胞移植修复关节软骨损伤治疗进展。方法:以Tissue engineering,cell transplantation,articular cartilage defects为检索词,检索Pubmed数据库(1993-01/2008-12);以组织工程,细胞移植,关节软骨损伤为检索词,检索CNKI数据库(2000-01/2008-12)。文献检索语种限制为英文和中文。纳入与关节软骨损伤以及分类密切相关性研究,组织工程种子细胞移植技术相关性应用研究。排除重复性研究。以种子细胞的存活和迁移,以及移植后关节功能的恢复和不良反应为评价指标。结果与结论:计算机初检得到201篇文献,根据纳入排除标准,对组织工程细胞移植修复关节软骨损伤的研究进行分析。临床上,创伤性或骨关节炎造成的关节软骨损伤较为常见,关节软骨自身修复能力差,一旦损伤将很难修复。组织工程细胞移植技术的出现为成功治愈关节软骨损伤带来了新的希望。在动物模型和临床研究中,细胞移植治疗关节软骨损伤已经取得良好的修复效果,但这一技术仍有改进的余地。目前的研究集中在如何从技术上改善组织工程3要素,即细胞,生物支架材料和生物活性因子。自体软骨再生仍然是关节软骨缺损修复的理论支柱,但进一步的研究需要优化其再生效果以及维持更加稳定的软骨细胞表型等等。组织工程细胞移植修复关节软骨损伤疗效较好,随着目前组织工程研究的深入,细胞移植修复技术有望成为临床上治疗关节软骨损伤的新方法。     

自体、异体骨软骨移植及组织工程材料修复的关节软骨损伤

背景：关节软骨损伤的修复已成为近年来医学基础研究的一个重要领域。由于关节软骨损伤后不易修复,决定了关节软骨损伤的修复是热点中的难点。目的：概述能够对关节软骨损伤进行修复和功能重建的生物材料,为选择理想的组织工程支架材料提供一种理论上的选择。方法：由第一作者通过计算机检索1989到2014年PubMed数据库和中国知网数据库。英文检索词为“articular cartilage injury,bone graft,tissue engineering scaffold materials”,中文检索词为“关节软骨损伤、骨移植、组织工程支架材料”。检索近年来关于关节软骨的结构和功能、不同关节软骨损伤修复材料的选择及修复过程中影响因素等方面的相关文献,针对目前软骨损伤修复材料的应用作一个较系统的回顾及总结,分别对软骨修复材料各自优缺点进行综合评述,从材料学的视角介绍了几种软骨修复材料在软骨组织工程支架中的应用情况,在此基础上对临床软骨损伤修复提供一种理论上的选择。结果与结论：常用的软骨修复材料包括自体、异体骨软骨移植材料,胶原、透明质酸钠和壳聚糖等天然高分子材料。自体、异体骨软骨移植的修复方法只能暂时的缓解疼痛,修复组织容易发生退变,都不能成功修复损伤软骨,与这些已经投入临床的技术相比,尚处在实验研究阶段的组织工程学技术的临床研究仍在不断进行,在众多关节软骨修复材料中,无论是自体移植材料还是组织工程支架材料其生物力学性能各有不同,且目前还无法再造与天然生成的软骨具有相同力学性能的软骨组织。中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

海藻酸钠支架复合组织工程化软骨细胞修复兔佐剂性关节炎膝关节软骨缺损的实验研究

目的 探讨海藻酸钠支架复合组织工程化软骨细胞对兔佐剂性关节炎膝关节软骨缺损修复的影响.方法 将新西兰白兔分为正常对照组、佐剂性模型组和海藻酸盐支架治疗组.模型组和治疗组兔膝关节内注入弗氏佐剂建立佐剂性关节炎模型.抽取治疗组兔左后健侧肢体的骨髓,用Percoll法分离出自体骨髓间充质干细胞(ABMSC),体外培养传代至P3代并诱导分化为软骨细胞.将软骨细胞与海藻酸钠支架混合注入治疗组的病变膝关节.对照组和模型组关节注射等量的生理盐水.海藻酸钠支架复合组织工程化软骨细胞治疗1个月后处死兔,应用Ⅱ型胶原免疫组织化学法染色和HE染色,观察各组兔的膝关节关节软骨缺损的修复情况.结果 诱导成功软骨细胞且生长良好,呈现明显的纺锤体形,细胞成活率达98.5％.软骨细胞与海藻酸钠复合后体外培养显示细胞生长旺盛,增殖成株状或岛状,株状细胞团周围有类似的软骨陷窝形成,细胞排列密集,核圆形.组织形态学结果显示,治疗组与模型组比较,治疗组关节炎症反应明显减轻,关节Ⅱ型胶原阳性软骨细胞显著增高,软骨缺损得到明显修复.结论 海藻酸钠支架复合组织工程化软骨细胞对兔佐剂性关节炎膝关节软骨缺损有一定的修复作用.     

骨髓基质干细胞和软骨组织工程

关节软骨是透明软骨 ,它是一种特殊的结缔组织 ,由单一的软骨细胞、纤维和基质构成。软骨组织具有自身独特的生理学特点 ,无血管 ,无神经 ,无淋巴引流 ,在关节腔内仅靠滑液来获取营养 ,其代谢主要以无氧酵解为主等决定了它极其有限的再生能力。临床上由于创伤、炎症肿瘤等原因导致的关节软骨损伤、缺失极为常见 ,且常继发骨关节炎 ,严重影响关节的功能。目前临床上多通过自体或异体移植成形的软骨或具有成软骨潜能的组织如骨膜、软骨膜等来治疗关节软骨的缺损 ,这些组织移植后能生成透明软骨样组织 ,但其生物学性能、耐磨性、韧性均欠佳 ,易…     

组织工程与骨关节损伤：置换与修复

- 文题导读 - 7832 人工髋关节摩擦界面的选择 7833 髋关节置换术后假体周围感染机制及治疗 7834 骨质疏松患者的髋关节置换假体 7835 髋部骨折的手术修复及围手术期处理 7837 高龄股骨转子间骨折的治疗选择：远端稳定生物型股骨柄人工股骨头置换 7838 高龄转子间骨折的修复 7839 股骨近段良性肿瘤手术方式与效果分析：关节置换还是内固定 7841 富血小板血浆治疗膝骨性关节炎 7842 膝关节损伤的修复与置换 7843 膝关节骨性关节炎的分期治疗 7845 膝关节置换后的疼痛管理 7846 膝关节置换中的3D打印技术 7847 胫骨平台骨折与全膝关节置换 7848 老年肱骨近端3、4部分骨折的外科治疗：内固定还是肩关节置换？ 7850 中西医结合补肾活血法对关节损伤置换与修复的思考 7851 非骨水泥型全涂层短柄假体的设计特征与临床应用 7853 骨关节肿瘤型假体的研究与应用现状 7855 人工跖趾关节置换 7856 3D打印模块与关节周围皮肤缺损 7857 关节软骨的玻璃化冷冻与保存 7859 骨关节结核：骨病灶药物分布特点及缓释材料 7860 骨缺损仿生支架的研究与思考 7861 制备组织工程支架修复关节软骨损伤 7862 生物反应器内工程化软骨的三维动态构建 7864 自体骨髓间充质干细胞外基质支架在软骨组织工程中的应用 7867 股骨头缺损模型的建立及评估 7869 计算生物力学在骨科领域的应用与展望 7870 骨外固定技术在下肢关节外科的应用     

软骨修复材料在运动性膝关节软骨损伤修复中的作用

背景：评价软骨修复材料在膝关节软骨损伤修复中的效果,为医务、科研工作者的研究提供一定的借鉴。 方法：采用电子检索的方式,在万方数据库(http://www.wanfangdata.com.cn/)中检索2000-01/2011-03关于修复材料在膝关节软骨损伤研究的文章,关键词为“生物材料;关节软骨;缺损;修复”。排除重复研究、普通综述或Meta分析类文章,筛选纳入26篇文献进行评价。 结果：膝关节软骨损伤在运动性损伤中较为常见,现在主要的治疗方法是自体骨软骨移植修复膝关节软骨缺损。新型的软骨替代材料研究仍处于动物试验阶段,且在动物体内长期疗效及远期的生物力学变化还未有进一步的证实,进入临床试验更需要一个过程。 结论：关节软骨损伤修复的基础研究与临床治疗,虽仍存在许多重点和难点问题亟待探索,但关节软骨损伤修复正从生物材料移植向人工再造活性软骨的崭新阶段迈进。随着各种新型材料的研制和开发,关节软骨损伤修复研究将日益完善,并为临床奠定坚实的基础,应用前景十分广阔。     

Epiphyseal and physeal cartilage vascularization: A light microscopic and tritiated thymidine autoradiographic study of cartilage canals in newborn and young postnatal rabbit bone

The vascular pattern of newborn and early postnatal epiphyseal and physeal cartilage is integral to long bone development and differs from later postnatal patterns. In the present study, we supplement light microscopic histology with tritiated thymidine autoradiography to help assess the position of cartilage canals and the dynamics of cartilage vascularity in relation to growth. Tritiated thymidine labeling studies to assess cell proliferation activity were done by using 2 μc/g body weight intraperitoneal injections into newborn and 3-, 4-, and 7-day-old New Zealand white rabbits that were killed 1 hr after the injection. Proximal humeral, distal femoral, and third metatarsal epiphyses were assessed by routine histology and serial section autoradiography. Cartilage canals were seen in each epiphysis. Transphyseal vessels were seen in each epiphysis continuous from the epiphysis to the metaphysis or were present within the physis traversing the proliferating and hypertrophic cell zones. Histologic sections showed vessels from the perichondrium continuous with those of the epiphyseal cartilage canals at proximal humeral, distal femoral, and metatarsal epiphyses. Serial sections showed vascular buds and connective tissue cells lying in indentations at the periphery of and present within the epiphyseal cartilage. Autoradiographic studies showed extensive labeling of vessel wall cells and surrounding connective tissue cells of the cartilage canals (a) within the epiphyseal cartilage, (b) traversing the physis, and (c) within the epiphyseal cartilage but continuous with the perichondrial vessels. The labeling was always far more extensive than in the surrounding chondrocytes and was always present throughout the entire extent of the canals. In conclusion, the cell labeling activity strongly supports an active dynamic phenomenon underlying the vascularization of epiphyseal and physeal cartilage. Anat. Rec. 252:140–148, 1998. © 1998 Wiley-Liss, Inc.     

Distribution of cartilage thickness on the head of the human first metatarsal bone

Articular hyaline cartilage takes on the contours of the subchondral bone on which it lies, but its thickness varies between joints, within a single joint and within a single articular surface. Previous studies have correlated articular cartilage thickness distribution with the degree of stress and weight bearing on joint surfaces, but few studies have considered the thickness of the calcified cartilage in relation to these parameters. Here we report a correlation between the cartilage thickness distribution and weight bearing distribution on the head of the 1st metatarsal bone, a component of one of the major weight bearing joints in the lower extremity during the gait cycle. The greatest total and uncalcified articular cartilage thickness was found on the central and lateral distal aspects of the metatarsal head, a region that receives maximal ground reactive force during the propulsive phase of the normal gait cycle. Although the thickness of the calcified cartilage was correlated with the thickness of the uncalcified cartilage, it varied to a lesser extent across the articular surface than did that of the uncalcified cartilage.     

关节软骨个性化定制可行性研究及设计

简单回顾了人工关节修复、软骨材料研究以及个性化假体的应用情况.针对目前关节置换术在处理关节炎症等时的不足之处,结合上述几个方面的内容,第一次提出了定制型个性化人工软骨的概念.借鉴个性化假体设计的思路和方法,考虑到人工软骨的特殊性质,提出一种新的修复软骨缺损的方法,并探讨了其中的关键问题和实施步骤,为软骨缺损患者提供了一种最优的修复方法.     

The existence of the vomeronasal organ in postnatal chimpanzees and evidence for its homology with that of humans

It is currently thought that New World monkeys, prosimians, and humans are the only primates to possess vomeronasal organs (VNOs) as adults. Recent studies of the human VNO suggest that previous investigations on Old World primates may have missed the VNO. We examined nasal septa from the chimpanzee ( Pan troglodytes ) grossly and histologically for comparison with nasal septa from humans, Old World monkeys ( Macaca fascicularis , M. nemistrina ) and prosimian primates ( Microcebus murinus , Otolemur garnettii ). Grossly, chimpanzees had depressions on the nasal septum similar to fossae reported anterior to the VNO openings in humans. Histologically, chimpanzees and humans had bilateral epithelial tubes which were above the superior margin of the paraseptal cartilages (vomeronasal cartilage homologue). The epithelial tubes had a homogeneous ciliated epithelium. These structures were thus positionally and structurally identical to the human VNO and unlike the well-developed prosimian VNOs which were surrounded by vomeronasal cartilage. Macaques had no structures which resembled the VNO of either the prosimians or humans. The results demonstrate that the VNO is present postnatally in the chimpanzee and is almost identical to the human VNO in its anatomical position and histological structure. This in turn suggests that the reported absence of the VNO in at least some adult Old World primates is artifactual, and that further study may provide evidence for its existence in other species.     

关节软骨的仿生设计

人体滑膜关节中,天然关节软骨具有多重不可替代的特殊功能和重要作用.本研究从仿生学的视角,综述关节软骨的生物化学、组织形态学、病理学特征,以及生物材料学、生物力学和生物摩擦学性质;从结构、材料、功能三个方面对关节软骨进行宏、微观层次的仿生设计,建立关节软骨仿生设计模型;为带有"软垫轴承"的新型人工关节,以及仿生人工软骨的创新设计与制造,提供理论和实践基础.     

Second harmonic generation imaging reveals a distinct organization of collagen fibrils in locations associated with cartilage growth

Purpose: The articular-epiphyseal cartilage complex (AECC) is responsible for the expansion of the bone ends and serves the function of the articular cartilage in juvenile mammals. Bundles of collagen fibrils surrounding cells were in the literature observed more frequently near the articular surface of the AECC. The articular surface, the perichondrium, and cartilage canals are interfaces where appositional growth of the AECC has been demonstrated. The current study aimed to evaluate the potential of second harmonic generation (SHG) to locate the collagen fibril bundles near the articular surface and to examine whether a comparable collagen fibril organization could be observed near the other interfaces of the AECC. Materials and methods: The study included the femoral condyle of four piglets aged 82–141 days. The forward and backward scattered SHG, and their ratio, was analyzed across the AECC using objectives with different numerical aperture. Two-photon-excited fluorescence was used to visualize cells. Results: A similar pattern of collagen fibril organization was observed near the articular surface, around cartilage canals, and adjacent to the perichondrium. The pattern consisted of a higher ratio of forward to backward scattered SHG that increased relative to the surrounding matrix at lower numerical aperture. This was interpreted to reflect collagen fibril bundles in the territorial matrix of cells in these areas. Conclusions: The observed arrangement of collagen fibrils was suggested to be related to the presumed different growth activity in these areas and indicated that SHG may be used as an indirect and label-free marker for cartilage matrix growth.     

Extracellular Matrix Composition of Full-Thickness Defect Repair Tissue is Little Influenced by Exercise in Rat Articular Cartilage

Full-thickness articular cartilage defects in the femoral condyles of adult rats were examined four and eight weeks after injury. Quantitative polarized light microscopic analysis showed that birefringence of the tissue in the central repair area increased more in rats exercised on a treadmill. Glycosaminoglycan content in the repair tissue was also higher than in the intermit-tent active motion group at four weeks after injury, but by eight weeks the levels were similar in both groups. No normal-looking articular cartilage was formed in the lesions, and only in one animal type II collagen was observed in the superficial zone of repair tissue. No 3B3(-) antigenicity of the proteoglycans was seen during repair. In conclusion, exercise minimally modified the repair of full-thickness articular cartilage defects in adult rats. The repair in the exercised group may occur slightly faster in the early stages but no difference was seen at the eight week time interval between the exercised and the intermittently active group.     

A method for quantifying time dependent changes in MR signal intensity of articular cartilage as a function of tissue deformation in intact joints

A method is proposed to determine accurately the signal intensity changes of the articular cartilage from sectional MR images and its related cartilage deformation under compression in an intact joint. Image processing methods are developed to delineate and register the cartilage boundaries in consecutive MR images in order to track corresponding tissue sectors during the loading experiment. Regions of interest can then be defined and traced during the compression, making a spatial and temporal analysis of signal intensity changes possible. In addition, the cartilage deformation is calculated in the respective tissue sectors and is related to the MR signal changes. Using a fat-suppressed FLASH 3D sequence, the preliminary results showed location-dependent slight changes of the signal intensity varying from individual to individual. The quantitative analysis of the signal intensity changes as a function of cartilage deformation with magnetic resonance imaging (MRI) aims to characterize microstructural properties of the articular cartilage that may lead to a better understanding of degenerative joint disease.     

壳聚糖在软骨组织工程的应用

软骨组织工程的出现 ,为解决软骨修复这个临床难题提供了新的方案 ,然而目前软骨组织工程的热点在于寻找一种合适的生物载体材料。壳聚糖 (chitosan) ,一种人工合成的多聚糖材料 ,具有良好的生物相容性、可降解性和生物活性 ,可作为细胞三维生长支架 ,维持种子细胞新陈代谢和生长表型。本文将就壳聚糖的理化特性、生物活性和在软骨组织工程方面应用的状况及前景作一综述。     

RNA isolation from micro-quantity of articular cartilage for quantitative gene expression by microarray analysis

Isolation of quality RNA from articular cartilage has been challenging due to low cellularity and the high abundance of extracellular matrix and proteoglycan proteins. Recently developed methods for isolation of high quality RNA from cartilage are more applicable to larger cartilage specimens typically weighing at least 25 mg. While these methods generate RNA suitable for analysis, they are less successful with smaller tissue inputs. For the study of small focal defect cartilage specimens an improved RNA extraction method is needed. Here we report a protocol for direct RNA isolation from less than 3 mg of wet weight rabbit articular cartilage for quantitative microarray gene profiling. This protocol is useful for identifying differentially expressed genes in chondrocytes following focal cartilage repair and can potentially be adopted for gene expression analysis of cartilage biopsy specimens from human joints.