关节镜下自体骨软骨移植修复软骨缺损的临床研究

目的取非负重区软骨替代负重区病变软骨,探讨软骨缺损的修复方式.方法对膝关节负重面软骨缺损的患者采用关节镜下非负重面自体骨软骨移植,根据缺损大小选择不同大小的骨软骨移植物,术后行CPM功能锻炼1周,6周后负重行走.结果术后随访3～24月,所有患者膝关节活动良好,疼痛症状基本消失,复查MRI示原软骨缺损区软骨表面光滑,移植物位置良好.结论关节镜下自体骨软骨移植效果良好,创伤小,避免同种异体移植产生的排斥反应及疾病的传播,是修复软骨缺损的好方式.     

关节镜下自体骨软骨移植并服温阳益髓方修复膝骨关节炎的软骨缺损

文题释义： 自体骨软骨移植：又称马赛克移植，是采用非负重面的骨软骨塞移植于骨软骨缺损部位修复软骨缺损。优点是可提供含有成活软骨细胞的正常透明软骨而不是纤维软骨修复骨软骨缺损，可保持与正常软骨几乎一致的生物力学及生物化学特性，术后Ⅰ期骨性愈合、恢复快；但是缺点是供区受损，移植块数量有限，大面积缺损无法修复，大移植块形态吻合度不够等。 软骨缺损：软骨包括弹性软骨、纤维软骨、透明软骨，其表面被透明白色软骨所包裹，因其光滑、摩擦系数小，其软骨缺损多因外伤所引起，应及早治疗，以防造成软骨合成和分解代谢的紊乱，引起骨性关节炎，治疗困难，一旦确诊需制动休息，控制体质量。 背景：温阳益髓方是课题组在右归丸的基础上根据多年临床实践总结所得，临床运用温阳益髓方治疗早期膝骨关节炎，对膝骨关节炎患者进行预防性和治疗性用药，取得了显著的临床疗效。 目的：探讨温阳益髓经验方联合关节镜下自体骨软骨移植治疗膝骨关节炎软骨缺损的临床疗效。 方法：采用关节镜下自体骨软骨移植治疗83例膝骨关节炎软骨缺损患者，其中男49例，女34例；年龄40-67(50.2±4.8)岁；病程1-27(12.3±5.2)个月；按照Doll氏分组法分为试验组和对照组。试验组行关节镜下自体骨软骨移植，术后第2天予温阳益髓经验方口服，300 mL，1剂/d，2次分服，连续用药2周为1个疗程，共3个疗程；对照组行关节镜下自体骨软骨移植。术前及术后3个月采用Lysholm评分评价膝关节功能情况，采用目测类比评分法(VAS)评价膝关节疼痛程度。研究方案的实施符合中国中医科学院望京医院的相关伦理要求(医院伦理批件号：221，时间：2014年2月)。结果与结论：①所有患者获得随访，时间3个月；②试验组治疗后3个月在膝关节疼痛、肿胀评分改善方面均优于对照组(P < 0.05)；③试验组治疗后3个月目测类比评分显著优于对照组(P < 0.001)；2组治疗后3个月目测类比评分显著均优于治疗前(P < 0.001)；④结果提示，关节镜下自体骨软骨移植联合温阳益髓法治疗膝关节小面积软骨缺损可明显改善患者术后疼痛和功能，临床疗效确切。 ORCID: 0000-0002-8762-6190(张鹏) 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     

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。     

自体骨软骨移植治疗HeppleⅤ型距骨骨软骨损伤的临床疗效评价

目的 探讨自体同侧膝关节非负重区骨软骨移植治疗HeppleⅤ型距骨骨软骨损伤的临床效果。方法 回顾性分析2014年8月至2016年7月于中国人民解放军联勤保障部队第960医院骨科住院治疗的6例HeppleⅤ型距骨骨软骨损伤患者,男4例,女2例,平均年龄43.8岁(33~53岁)。所有患者均采用开放手术方式,取同侧膝关节非负重区骨软骨移植物复合骨柱,压配填充距骨骨软骨损伤区域。分别采用视觉模拟评分法(VAS)评估患者术后踝关节疼痛改善情况,采用美国骨科足踝协会(AOFAS)踝后足评分细则评价踝关节功能改善情况。术后3个月时,行踝关节正侧位X线检查及踝关节CT(计算机断层扫描)检查,评估移植区骨软骨愈合情况。结果 所有患者术后均获得随访,术后平均随访30.5个月(23~44个月)。术后3个月及末次随访时,患者VAS评分分别为(2.2±0.8)分和(0.8±0.7)分,较术前的评分(5.5±1.4)分明显好转,差异有统计学意义(<0.05)。术后3个月及末次随访时的AOFAS踝后足评分分别为(81.5±2.7)分和(86.7±1.8)分,较术前评分(58.2±7.9)分明显改善,差异有统计学意义(<0.05)。术后3个月复查踝关节正侧位X线片和CT显示内踝截骨处及骨软骨移植区出现明显骨性愈合。所有患者均无供体部位疼痛。6例患者末次随访均无并发症发生。结论 利用同侧膝关节非负重区骨软骨移植治疗HeppleⅤ型距骨骨软骨损伤可有效缓解踝关节疼痛并改善踝关节功能,临床疗效显著。     

早期体内力学刺激促进藻酸钙复合自体软骨细胞修复羊关节负重区软骨缺损的实验研究

目的观察膝关节持续被动活动仪(CPM)体内力学刺激对组织工程软骨修复大动物关节负重区软骨缺损效果的影响。方法研究、设计和制造能够适用于体内力学刺激羊膝关节软骨缺损修复的膝关节连续被动活动仪(CPM);将实验动物(山羊膝关节双髁负重区制造直径6 mm软骨缺损)分为三组:空白组:单纯缺损未植入修复组织;藻酸钙+骨膜+细胞组:藻酸钙复合自体软骨细胞凝胶植入软骨缺损区,自体骨膜覆盖缺损区;藻酸钙+骨膜+细胞+CPM组:藻酸钙复合自体软骨细胞凝胶植入软骨缺损区,自体骨膜覆盖缺损区,术后早期接受CPM锻炼。分别于术后3个月、6个月、12个月(12个月组仅包括CPM力学刺激组)取材,通过修复组织的大体、组织学观察及其评分比较3组软骨修复效果。结果藻酸钙复合软骨细胞能够较好地修复羊负重区关节面软骨缺损,将缺损修复的大体观察、组织学等结果进行单因素统计学分析,发现接受体内CPM力学刺激组效果最好,其修复组织中透明软骨比例最多,其次为藻酸钙+骨膜+细胞组。结论膝关节持续被动活动仪(CPM)体内力学刺激能够促进组织工程软骨修复大动物关节负重区软骨缺损的效果。     

关节镜下可吸收软骨钉治疗膝关节骨软骨损伤

背景：关节软骨骨折的手术治疗是骨关节外科常见难题,骨软骨骨折块缺乏有效的固定物,各种治疗方法的疗效也缺乏长期临床观察。 目的：探讨关节软骨损伤在关节镜下采用可吸收软骨钉固定治疗的临床疗效。 方法：纳入19例膝关节骨软骨缺损患者,在关节镜下修整损伤区及骨软骨骨折块以自身增强聚丙烯可吸收软骨钉固定,内固定后24 h拔出负压引流管,抗生素预防感染不超过48 h,充分镇痛条件下持续被动活动关节,膝关节铰链支具固定6周后完全负重行走。 结果与结论：19例患者均获得3个月-2年随访,平均13.2个月。修复后患者2周-3个月恢复社会活动。膝关节Lysholm评分为(83.25±5.63)分,tegner运动评级6.1±0.87,修复前后配对t检验,差异有显著性意义(P < 0.05)。说明膝关节骨软骨损伤采用可吸收软骨钉固定可有效固定脱落的骨软骨块,促进软骨修复,改善膝关节功能。     

聚乙烯醇/羟基磷灰石复合水凝胶修复膝关节软骨缺损的组织相容性

背景：将羟基磷灰石与聚乙烯醇水凝胶复合之后应用于软骨缺损修复中,可在软骨连接部位产生良好的生物活性,有效促进骨细胞的生长,提高植入材料的稳定性和生物活性。 目的：观察聚乙烯醇/羟基磷灰石复合水凝胶修复兔膝关节软骨缺损的组织相容性。 方法：取20只新西兰大白兔,随机分为空白对照组(n=6)与实验组(n=14),构建单侧膝关节软骨缺损模型,空白对照组不予以修复,实验组予以聚乙烯醇/羟基磷灰石复合水凝胶修复。术后4,8,12周获取膝关节标本进行大体观察及组织学观察。 结果与结论：空白对照组关节软骨面在术后12周内始终未得到修复,软骨下缺损存在肉芽组织充填现象,组织学也未见明显修复。实验组术后4周可见聚乙烯醇/羟基磷灰石复合水凝胶填充于缺损处,与周围软骨组织之间连接紧密,且存在清晰的界限,未出现细胞长入情况;至12周时,聚乙烯醇/羟基磷灰石复合水凝胶呈白色、半透明状,表面平坦,与周围软骨组织之间存在清晰界限,两者交界面存在软骨细胞大量增殖现象,与周围组织发生紧密结合,二者之间无间隙,底部与软骨下骨紧密连接,并存在骨样组织长入。表明聚乙烯醇羟基磷灰石复合水凝胶修复兔膝关节软骨缺损具有良好的组织相容性。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

异体和自体全厚关节软骨移植的实验研究

异体和自体新鲜全厚关节软骨移植共３２只新西兰兔。异体移植有排斥反应，关节软骨完全吸收，缺损区被宿主新生软骨修复。自体移植的软骨完全有活力，植骨裂隙由新生软骨修复。关节软骨无再生能力，修复软骨来自骨髓松质骨的间充质细胞，术后控制性关节运动能促使软骨生长。新形成的软骨基质不及正常软骨基质质量好，甚至正常软骨与修复软骨间存在裂隙，不能完全融合。     

软骨移植与软骨微骨折方法修复关节软骨损伤

背景：文献介绍微骨折与骨软骨移植治疗关节软骨缺损都有效,均为目前临床治疗手段。 目的：比较微骨折与骨软骨移植在关节软骨缺损治疗中的实施效果。 方法：回顾性分析50例(50个膝关节)关节软骨缺损患者的临床资料。按照外科修复方式分为2组,每组25例。骨软骨移植组患者采用自体骨软骨移植修复膝关节软骨缺损;微骨折组患者运用微骨折方法修复膝关节软骨缺损。两组患者均随访超过24个月,比较两组患者的膝关节美国特种外科医院(Hospital for Special Surgery,HSS)评分及临床疗效,观察两组患者不良反应和并发症。 结果与结论：骨软骨移植组患者的膝关节HSS评分> 85分和60-85分患者数量明显多于微骨折组(P < 0.05),骨软骨移植组总有效率显著高于微骨折组(92%,60.0%,P < 0.05)。两组患者均无并发症发生。结果表明骨软骨移植在关节软骨缺损治疗中较微骨折具有较好的实施效果。 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;组织工程全文链接：     

以羊膜为载体培养游离软骨细胞修复兔关节软骨缺损

目的：探讨膜结构为载体培养游离软骨细胞修复软骨缺损的可行性。方法：以兔羊膜为载体将体外培养的同种异体游离软骨细胞植于兔左侧股骨外踝软骨缺损区，分别于4、8、12周处死动物，整个膝关节被解剖，进行大体观察、组织学评价、电镜观察及SRY基因性别鉴定，并以兔体的右膝关节做为对照。结果：术后4、8、12周大体、组织学、电镜观察显示软骨缺损区新生了透明软骨，SRY基因性别鉴定证明新生的软骨来源于移植的同种异体软骨细胞；而对照组则仅见纤维组织样的修复组织。结论：以羊膜为载体进行同种异体软骨细胞移植能够修复关节软骨缺损。     

Autologous osteochondral transplantation for the treatment of chondral defects of the knee

Full-thickness chondral defects of weight-bearing articular surfaces of the knee are a difficult condition to treat. Our aim is to evaluate the mid- and long-term functional outcome of the treatment of osteochondral defects of the knee with autologous osteochondral transplantation with the OATS technique. Thirty-six patients (37 procedures) were included in this study. Twenty-three patients were male and thirteen were female with a mean age of 31.9 years (range: 18-48 years). The cause of the defect was OCD in 10 cases, AVN in 2, lateral patellar maltracking in 7, while in the remaining 17 patients the defect was post-traumatic. The lesion was located on the femoral condyles in 26 cases and the patellofemoral joint in the remaining 11. The average area covered was 2.73 cm(2) (range: 0.8-12 cm(2)) and patients were followed for an average of 36.9 months (range: 18-73 months). The average score in their Tegner Activity Scale was 3.76 (range: 1-8), while their score in Activities of Daily Living Scale of the Knee Outcome Survey ranged from 18 to 98 with an average of 72.3. Thirty-two out of 37 patients (86.5%) reported improvement of their pre-operative symptoms. All but 5 patients returned to their previous occupation while 18 went back to sports. No correlation was found between patient age at operation, the size or site of the chondral lesion and the functional outcome. We believe that autologous osteochondral grafting with the OATS technique is a safe and successful treatment option for focal osteochondral defects of the knee. It offers a very satisfactory functional outcome and does not compromise the patient's future options.     

Critical-sized cartilage defects in the equine carpus

Aim: The horse joint, due to its similarity with the human joint, is the ultimate model for translational articular cartilage repair studies. This study was designed to determine the critical size of cartilage defects in the equine carpus and serve as a benchmark for the evaluation of new cartilage treatment options. Material and Methods: Circular full-thickness cartilage defects with a diameter of 2, 4, and 8 mm were created in the left middle carpal joint and similar osteochondral (3.5 mm in depth) defects in the right middle carpal joint of 5 horses. Spontaneously formed repair tissue was examined macroscopically, with MR and µCT imaging, polarized light microscopy, standard histology, and immunohistochemistry at 12 months. Results: Filling of 2 mm chondral defects was good (77.8 ± 8.5%), but proteoglycan depletion was evident in Safranin-O staining and gadolinium-enhanced MRI (T_1Gd). Larger chondral defects showed poor filling (50.6 ± 2.7% in 4 mm and 31.9 ± 7.3% in 8 mm defects). Lesion filling in 2, 4, and 8 mm osteochondral defects was 82.3 ± 3.0%, 68.0 ± 4.6% and 70.8 ± 15.4%, respectively. Type II collagen staining was seen in 9/15 osteochondral defects but only in 1/15 chondral defects. Subchondral bone pathologies were evident in 14/15 osteochondral samples but only in 5/15 chondral samples. Although osteochondral lesions showed better neotissue quality than chondral lesions, the overall repair was deemed unsatisfactory because of the subchondral bone pathologies. Conclusion: We recommend classifying 4 mm as critical osteochondral lesion size and 2 mm as critical chondral lesion size for cartilage repair research in the equine carpal joint model.     

Repair of articular cartilage defect by cell transplantation

Full-thickness articular cartilage defects are a major clinical problem; however, at present there is no treatment that is widely accepted to regeneratively repair these lesions. The current therapeutic approach is to drill or abrade the base of the defect to expose the bone marrow with its cells and growth factors. This usually results in a repaired tissue of fibrocartilage that functions poorly in the loaded joint environment. Recently, autologous cultured chondrocyte transplantation and mosaic plasty were explored. We can repair small articular cartilage defects using these methods, although their effectiveness is still controversial. We have reported that transplantation of allogeneic chondrocytes embedded in collagen gels or allogeneic chondrocytes cultured in collagen gels could repair articular cartilage defect in a rabbit model. We also reported that autologous culture-expanded bone marrow mesenchymal cell transplantation could repair articular cartilage defect in a rabbit model. This procedure offers expedient clinical use, given that autologous bone marrow cells are easily obtained and can be culture-expanded. We transplanted autologous culture-expanded bone marrow cells into the cartilage defect of the osteoarthritic knee joint on 11 patients at the time of high tibial osteotomy. As early as 6.8 weeks after transplantation, the defect was covered with white soft tissue, in which slight metachromasia was histologically observed. Thirty-three weeks after transplantation, the repaired tissue had hardened. Histologically, repaired tissues showed stronger metachromasia and a partial hyaline cartilage-like appearance. This procedure may prove a promising method by which to repair articular cartilage defects.     

Mechanical resistance of biological repair cartilage: comparative in vivo tests of different surgical repair procedures

The former common knowledge that cartilage lesions do not heal has been modified over the last few years due to new technologies. For repair of deeper circumscribed lesions osteochondral press-fit grafting and tissue engineering are used in clinical application. The histological data of the hyaline-like tissue obtained by engineering are just as satisfactory as the surviving grafted hyaline cartilage on top of osteochondral cylinders. But comparative studies are still lacking. To fill the gap and with a view to repairing larger osteoarthritic defects we have performed an in vivo study on 16 goats. Three months after the creation of a full thickness wide cartilage defect on the femoral condyle with harvesting of cartilage samples for tissue cultures we performed secondary cartilage repair procedures on the installed osteoarthritis areas: 1) grafting with autogenic osteochondral press-fit cylinders from the opposite knee, 2) autologous engineered chondrocyte grafting under periosteal flaps, 3) both in combination. The harvesting defects were either left as controls or filled with a hyaluronate fleece. After eight months the repaired areas and the harvesting defects were examined for cartilage stiffness as a novel comparative parameter. Compared to normal the cartilage on top of osteochondral grafts is considerably stiffer. Engineered cartilage is weaker than normal. Spontaneously ingrown fibrous cartilage is much weaker even with a carrier fleece. A combination of osteochondral press-fit grafts with engineered autologous cells restores biomechanical qualities to repaired larger degenerative cartilage defects.     

Safety and efficacy of engineered tissue composed of silk fibroin/collagen and autologous chondrocytes in two patients with cartilage defects: A pilot clinical trial study

BackgroundThe objective of this pilot clinical trial study was to evaluate safety and effectiveness of the newly engineered tissue composed of autologous chondrocytes and collagen/fibroin scaffold in repair of osteochondral defects.MethodsWe implemented a pilot clinical study in two patients with knee osteochondral lesions using engineered tissue composed of scaffold and autologous chondrocytes. Patients were clinically evaluated using the International Repair Cartilage Society score and magnetic resonance imaging (MRI) for one year.ResultsImproved clinical outcomes and objective scores indicated a normal or nearly normal knee in both patients. International Knee Documentation Committee score was upgraded from 34.5 at baseline to 72.4 in the first patient, and 28.7 to 81.6 in the second patient. Visual analogue scale, showing the suffering pain score, was lowered from 8 to 0 in both patients, Western Ontario and McMaster Universities Osteoarthritis Index score representing the physical ability of the patients was changed from 68.1 to 87.1 in Patient 1 and 58.3 to 87.1 in Patient 2, the knee function score, related to the functional ability of the knee, was improved from 70 to 100 in the first patient and from 45 to 91 in the second patient. MRI showed great coverage and integration of the graft in patients, with no effusion, decreased edema and cartilage formation signals.ConclusionsThe functional and clinical outcomes alongside MRI data showed promising results for regenerating osteochondral defects. A randomized clinical trial study is required to confirm feasibility of this novel engineered tissue in repair of osteochondral defects.     

Repair of articular cartilage defects with a novel injectable in situ forming material in a canine model

We developed an ultra-purified in situ forming gel as an injectable delivery vehicle of bone marrow stromal cells (BMSCs). Our objective was to assess reparative tissues treated with autologous BMSCs implanted using the injectable implantation system into osteochondral defects in a canine model. Forty-eight osteochondral defects in the patella groove of the knee joint were created in 12 adult beagle dogs (two defects in each knee). The defects were divided into a defect group (n = 16), an acellular novel material implantation (material) group (n = 16), and a BMSCs implantation using the current vehicle system (material with BMSCs) group (n = 16). The reparative tissues at 16 weeks postoperatively were assessed through gross, histological, and mechanical analyses. The reparative tissues of the material with BMSCs group were substituted with firm and smooth hyaline-like cartilage tissue that was perfectly integrated into the host tissues. This treatment group obviously enhanced the subchondral bone reconstruction. The compressive modulus of the reparative tissues was significantly higher in the material with BMSCs group than the other groups. This study demonstrated that the implantation of BMSCs using our novel in situ forming material induced a mature hyaline-like cartilage repair of osteochondral defects in a canine model.     

多种特殊状态下关节软骨缺损修复的组织工程技术

文题释义： 生长板：是位于儿童长骨末端的软骨组织结构,生长板中的软骨细胞可不断增生、成熟、肥大并发生骨化过程,使长骨增长。当长骨生长至一定程度,生长板软骨逐渐被成熟骨组织取代,长骨至此也停止生长。 特殊状态：文章提及的特殊状态即指关节软骨缺损的临床治疗中常见的阻碍因素,即全层软骨缺损及骨软骨缺损、生长板缺损、负重区软骨缺损、炎症状态下(骨性关节炎、风湿性关节炎)的软骨缺损。 背景：应用组织工程学技术可获得良好的关节软骨再生,但多为生理状态下小面积缺损的单纯修复。然而临床上的软骨缺损常伴随骨性关节炎、类风湿性关节炎等基础疾病,且缺损的位置、范围、深度均不确定,给软骨组织修复带来了很大挑战。 目的：总结不同位置和炎症状态下软骨缺损的修复方式。 方法：检索PubMed数据库和CNKI数据库,英文检索词为“cartilage defect regeneration,osteochondral,growth plate,weight-bearing area,inflammatory”,中文检索词为“关节软骨缺损,骨软骨,生长板,负重区,炎症”,检索建库至2019年3月发表的相关文献。共检索到相关文献209篇,按照纳入与排除标准,最终纳入86篇文献进行总结。 结果与结论：针对各种特殊状态下的关节软骨缺损,其修复目标和策略是不同的：全层软骨和骨软骨结构缺损多采用具有多层结构的支架,旨在修复软骨特有的分层结构及软骨下骨结构,同时避免新生软骨内异位骨化的问题;生长板缺损的修复关键在于避免长骨成熟后发生畸形,因此在修复支架内应添加胰岛素样生长因子、骨发生形态蛋白7等生长因子,以持续刺激生长板的修复并发挥骨生长的生理功能;负重区软骨修复则需要修复支架具有良好的力学性能,负重时不会发生严重形变及结构破坏,同时新生的软骨组织具有足够的力学强度以支撑持续的纵向压力和磨损;炎症状态下的软骨缺损则要同时治疗炎症与软骨缺损,间充质干细胞的引入可同时发挥免疫调节及组织再生功能,以使疾病达到彻底治疗的目标。ORCID: 0000-0001-9443-8158(陈劲松) 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     

Repair of osteochondral defects in rabbits with ectopically produced cartilage

Cartilage has poor regenerative capacity. Donor site morbidity and interference with joint homeostasis should be considered when applying the autologous chondrocyte transplantation technique. The use of ectopically produced cartilage, derived from periosteum, might be a novel method to heal cartilage defects. Ectopic cartilage was produced by dissecting a piece of periosteum from the tibia of rabbits. After 14 days the reactive tissue at the dissection site was harvested and a graft was cored out and press-fit implanted in an osteochondral defect in the medial condyle of the femur with or without addition of hyaluronan. After 3 weeks and 3 months the repair reaction was evaluated by histology. Thionine- and collagen type II-stained sections were evaluated for graft viability, ingrowth of the graft, and joint surface repair. Empty defects remained empty 3 weeks after implantation, ectopic cartilage filled the defect to the level of the surrounding cartilage. Histologically, the grafts were viable, consisting mainly of cartilage, and showed a variable pattern of ingrowth. Three months after implantation empty defects with or without hyaluronan were filled primarily with fibrocartilaginous tissue. Defects treated with ectopic cartilage contained mixtures of fibrocartilaginous and hyaline cartilage. Sometimes a tidemark was observed in the new articular cartilage and the orientation of the cells resembled that of healthy articular cartilage. Subchondral bone repair was excellent. The modified O'Driscoll scores for empty defects without and with hyaluronan were 12.7 +/- 6.4 and 15.3 +/- 3.2; for treated defects scores were better (15.4 +/- 3.9 and 18.2 +/- 2.9). In this conceptual study the use of ectopic cartilage derived from periosteum appears to be a promising novel method for joint surface repair in rabbits.