Effects of a cultured autologous chondrocyte-seeded type II collagen scaffold on the healing of a chondral defect in a canine model.

Using a previously established canine model for repair of articular cartilage defects, this study evaluated the 15-week healing of chondral defects (i.e., to the tidemark) implanted with an autologous articular chondrocyte-seeded type II collagen scaffold that had been cultured in vitro for four weeks prior to implantation. The amount and composition of the reparative tissue were compared to results from our prior studies using the same animal model in which the following groups were analyzed: defects implanted with autologous chondrocyte-seeded collagen scaffolds that had been cultured in vitro for approximately 12 h prior to implantation, defects implanted with autologous chondrocytes alone, and untreated defects. Chondrocytes, isolated from articular cartilage harvested from the left knee joint of six adult canines, were expanded in number in monolayer for three weeks, seeded into porous type II collagen scaffolds, cultured for an additional four weeks in vitro and then implanted into chondral defects in the trochlear groove of the right knee joints. The percentages of specific tissue types filling the defects were evaluated histomorphometrically and certain mechanical properties of the repair tissue were determined. The reparative tissue filled 88+/-6% (mean+/-SEM; range 70-100%) of the cross-sectional area of the original defect, with hyaline cartilage accounting for 42+/-10% (range 7-67%) of defect area. These values were greater than those reported previously for untreated defects and defects implanted with a type II collagen scaffold seeded with autologous chondrocytes within 12 h prior to implantation. Most striking, was the decreased amount of fibrous tissue filling the defects in the current study, 5+/-5% (range 0-26%) as compared to previous treatments. Despite this improvement, indentation testing of the repair tissue formed in this study revealed that the compressive stiffness of the repair tissue was well below (20-fold lower stiffness) that of native articular cartilage.     

Minced cartilage without cell culture serves as an effective intraoperative cell source for cartilage repair.

Traumatic articular cartilage injuries heal poorly and may predispose patients to the early onset of osteoarthritis. One current treatment relies on surgical delivery of autologous chondrocytes that are prepared, prior to implantation, through ex vivo cell expansion of cartilage biopsy cells. The requirement for cell expansion, however, is both complex and expensive and has proven to be a major hurdle in achieving a widespread adoption of the treatment. This study presents evidence that autologous chondrocyte implantation can be delivered without requiring ex vivo cell expansion. The proposed improvement relies on mechanical fragmentation of cartilage tissue sufficient to mobilize embedded chondrocytes via increased tissue surface area. Our outgrowth study, which was used to demonstrate chondrocyte migration and growth, indicated that fragmented cartilage tissue is a rich source for chondrocyte redistribution. The chondrocytes outgrown into 3-D scaffolds also formed cartilage-like tissue when implanted in SCID mice. Direct treatment of full-thickness chondral defects in goats using cartilage fragments on a resorbable scaffold produced hyaline-like repair tissue at 6 months. Thus, delivery of chondrocytes in the form of cartilage tissue fragments in conjunction with appropriate polymeric scaffolds provides a novel intraoperative approach for cell-based cartilage repair.     

Evaluation of articular cartilage with 3D-SPGR MRI after autologous chondrocyte implantation

To assess the maturation process of the cartilage after autologous chondrocyte implantation (ACI), we performed a longitudinal study with three-dimensional spoiled gradient-recalled (3D-SPGR) magnetic resonance imaging (MRI). Five knees of five patients on which ACI of the femoral condyle was performed were studied. The signal intensity of reparative tissue approached that of normal articular cartilage with time. The volume of reparative tissue remained at an almost constant level after implantation. During second-look arthroscopy, the areas on which ACI was performed were covered with hyaline-like cartilage, and the reparative tissue removed by biopsy consisted of normal chondrocytes and extracellular matrix. The increased signal intensity of the reparative tissue represents maturation of implanted autologous chondrocytes. 3D-SPGR MRI is thought to be useful for evaluating reparative tissue after autologous chondrocyte implantation.     

Immature porcine knee cartilage lesions show good healing with or without autologous chondrocyte transplantation

OBJECTIVE: The purpose of this study was to find out how deep chondral lesions heal in growing animals spontaneously and after autologous chondrocyte transplantation. METHODS: A 6mm deep chondral lesion was created in the knee joints of 57 immature pigs and repaired with autologous chondrocyte transplantation covered with periosteum or muscle fascia, with periosteum only, or left untreated. After 3 and 12 months, the repair tissue was evaluated with International Cartilage Repair Society (ICRS) macroscopic grading, modified O'Driscoll histological scoring, and staining for collagen type II and hyaluronan, and with toluidine blue and safranin-O staining for glycosaminoglycans. The repair tissue structure was also examined with quantitative polarized light microscopy and indentation analysis of the cartilage stiffness. RESULTS: The ICRS grading indicated nearly normal repair tissue in 65% (10/17) after the autologous chondrocyte transplantation and 86% (7/8) after no repair at 3 months. At 1 year, the repair tissue was nearly normal in all cases in the spontaneous repair group and in 38% (3/8) in the chondrocyte transplantation group. In most cases, the cartilage repair tissue stained intensely for glycosaminoglycans and collagen type II indicating repair tissue with true constituents of articular cartilage. There was a statistical difference in the total histological scores at 3 months (P=0.028) with the best repair in the spontaneous repair group. A marked subchondral bone reaction, staining with toluidine blue and collagen type II, was seen in 65% of all animals. CONCLUSIONS: The spontaneous repair ability of full thickness cartilage defects of immature pigs is significant and periosteum or autologous chondrocytes do not bring any additional benefits to the repair.     

Autologous chondrocyte implantation--technique and long-term follow-up

Cartilage has a limited capacity for self repair after injury. This biological deficiency has led to a variety of surgical attempts to improve the repair of injured articular cartilage surfaces over the past 50 years. The first example of clinical cartilage tissue engineering was performed in 1987 when a knee with an articular cartilage defect on the femoral condyle was treated by implanting the patient's own chondrocytes that had been expanded in vitro into the defect in combination with a covering mechanical membrane-the periosteum. This technology is either termed autologous chondrocyte transplantation (ACT) or autologous chondrocyte implantation (ACI). Today, many modifications of the technique exist, from the first generation to now second and third generations of chondrocyte implantation. This paper describes the basic techniques for the clinical use of chondrocyte implantation and gives an update on the clinical results.     

Analysis of rabbit articular cartilage repair after chondrocyte implantation using optical coherence tomography

OBJECTIVE: To evaluate the utility and limitations of optical coherence tomography (OCT) for immediate, high-resolution structural analysis of rabbit articular repair tissue following chondrocyte implantation without excising or sectioning the specimen. METHODS: Full thickness articular cartilage defects were created in the patellar grooves of 30 adult rabbit knee joints. Allogenic cultured chondrocytes embedded in collagen gels were implanted into the surgical defects. A periosteal patch was then sutured over the chondrocyte-collagen composites. Six animals per time point were sacrificed at 2, 4, 8, 12 and 24 weeks after surgery. The repair tissues were sequentially analysed by arthroscopic surface imaging, OCT, and histology. The resulting images were compared to determine qualitative and quantitative features of surface roughness, repair tissue integration, and micro-architecture. Statistical analysis was performed using Student's t -testing and linear regression. RESULTS: OCT was able to identify the bone and cartilage interface in normal rabbit articular cartilage and regenerated cartilage at 24 weeks post chondrocyte implantation. OCT was able to identify hypertrophy at 4 and 8 weeks, and subtle surface fibrillations at 24 weeks, comparable with histological analysis at low magnification (20x). More importantly, OCT was able to detect embedded gaps between the repair tissue and surrounding host cartilage. CONCLUSION: Close correlation was observed between OCT and histological analysis of morphological features important to the assessment of articular cartilage repair. These results demonstrate that OCT is capable of providing immediate 'optical biopsy' of the rabbit articular cartilage repair tissue without damaging the specimen, and suggest that this new technique, if integrated with an arthroscope, can potentially be used in longitudinal studies of articular cartilage repair in vivo.     

同种异体组织工程化软骨修复关节软骨缺损

目的　探讨应用同种异体组织工程化软骨修复软骨缺损的可行性。方法　取新西兰大白兔双膝关节软骨细胞 ,经体外培养扩增 ,与PlruonicF12 7混合 ,植入人为造成的异体兔膝关节软骨缺损。结果　空白对照组和材料对照组只见少许纤维组织修复 ,缺损凹陷 ;实验组 8周后关节软骨缺损区由部分白色透明样软骨组织充填 ,Masson三色染色见胶原分布较均匀 ,软骨陷窝多见 ,未见明显炎症现象。 16周后缺损完全修复 ,缺损表面较光滑 ,部分颜色呈淡兰色 ,软骨陷窝清晰 ,细胞与基质分布均匀 ,未见炎症和退变现象。结论　同种异体组织工程化软骨可用于修复关节软骨缺损。     

Management of focal chondral lesion in the knee joint

Articular cartilage does not contain vascular, nervous and lymphatic tissue and chondrocytes hardly participate in the healing or repair process of chondral tissue because of being surrounded by plenty of extracellular matrix. Therefore, the injury to articular cartilage frequently requires an operative treatment. The goal of surgical repair of articular cartilage is to regenerate nearly normal chondral tissue and prevent degenerative arthritis caused by the articular cartilage defect. Microfracture is a kind of cartilage repair procedure that makes a fibrin clot containing mesenchymal stem cells in the chondral lesion. Microfracture is a simple procedure but it has a disadvantage that the repaired tissue is fibrocartilage. Autologous chondrocyte implantation has an advantage that it implants fully differentiated chondrocytes to the lesion, which theoretically produces hyaline cartilage. Its disadvantages are that it is a two stage and a costly procedure. Osteochondral autograft transplantation is a one stage procedure and repairs the lesion with hyaline cartilage. But its limitation is the lack of donor site availability. Surgeons who understand the theoretical background, indications, surgical methods, rehabilitation, complications, and clinical course of cartilage repair procedures can achieve the goal of preventing degenerative arthritis.     

Magnetic resonance imaging of cartilage repair techniques

Magnetic resonance (MR) imaging offers a noninvasive method to assess cartilage repair, allowing objective evaluation of the repair tissue and insight into the natural history of cartilage repair procedures. MR imaging allows assessment of the percent fill, signal morphology of the repair tissue, subchondral bone and three-dimensional geometry of the joint. The information gained from MR imaging therefore plays a valuable role in patient follow-up after cartilage repair. This article discusses the MR imaging techniques available for the assessment of articular cartilage, including quantitative imaging techniques that allow assessment of cartilage biochemistry. The MR imaging appearance and assessment of microfracture, autologous chondrocyte implantation, and osteochondral autograft and allograft transplantation is reviewed.     

Autologous chondrocyte implantation for focal cartilage defects in athletes: histology and second-look arthroscopy

Abstract Previous studies of autologous chondrocyte implantation reported good results in the general population. This study was undertaken to evaluate outcomes in high-level competitive athletes. We tested the hypothesis that cartilage resurfacing with autologous chondrocytes is an effective treatment for symptomatic chondral lesions in high-level athletes. We prospectively evaluated 5 male athletes with large (3-10 cm²) symptomatic grade III-IV chondral injuries of the knee.Clinical evaluations were performed at baseline and 3, 6, 12, and 24 months after chondrocyte implantation. All patients underwent secondlook arthroscopy at one year and were evaluated macroscopically using a standardized scoring system. Three patients consented to biopsy and histological analysis of repair tissue at one or more years after implantation. Overall, scores of patients subjective ratings improved from a mean of 2.4 at baseline (poor: significant limitations affecting activities of daily living) to 9.4 (very good: only a few limitations with sports) at 12 months on a modified Cincinnati scale. All patients returned to pre-injury level of sports participation. Macroscopic evaluation showed tissue similar in appearance and consistency to normal cartilage. Histological results in 3 of 5 patients showed organization and type II collagen staining similar to normal cartilage. Autologous chondrocyte implantation successfully returned all patients to pre-injury levels of sports participation.Macroscopic and histologic evaluations showed repair tissue with the characteristics of normal cartilage.     

Cartilage resurfacing of the rabbit knee. The use of an allogeneic demineralized bone matrix-autogeneic perichondrium composite implant

A full-thickness articular-cartilage defect was created in the medial femoral condyles of 32 adult rabbits. The defects were filled with demineralized bone or a composite of demineralized bone and perichondrium. Results of cartilage repair were assessed after 12 weeks of implantation. We conclude that demineralized bone matrix used as a subchondral matrix in a cartilage repair model 1) stimulates and induces subchondral bone ingrowth, 2) provides a surface on which cartilage repair can proceed, and 3) can be utilized as a platform on which perichondrium can be fixed to provide a cellular source for cartilage repair. Repair tissue that developed from perichondrium was thicker, more closely resembled normal articular cartilage, and was of a less fibrous nature than the repair tissue that developed de novo on the demineralized bone matrix.     

Cartilage resurfacing of the rabbit knee: The use of an allogeneic demineralized bone matrix-autogeneic perichondrium composite implant

A full-thickness articular-cartilage defect was created in the medial femoral condyles of 32 adult rabbits. The defects were filled with demineralized bone or a composite of demineralized bone and perichondrium. Results of cartilage repair were assessed after 12 weeks of implantation. We conclude that demineralized bone matrix used as a subchondral matrix in a cartilage repair model 1) stimulates and induces subchondral bone ingrowth, 2) provides a surface on which cartilage repair can proceed, and 3) can be utilized as a platform on which perichondrium can be fixed to provide a cellular source for cartilage repair. Repair tissue that developed from perichondrium was thicker, more closely resembled normal articular cartilage, and was of a less fibrous nature than the repair tissue that developed de novo on the demineralized bone matrix.     

Current concepts in tissue engineering technique for repair of cartilage defect

Hunter's observation in 1743 that cartilage "once destroyed, is not repaired," has not essentially changed for 250 years. At present, there is no well-established procedure for the repair of cartilage defect with articular cartilage, which has the same biochemical and biomechanical properties as the surrounding normal intact cartilage. In 1994, transplantation of human autologous chondrocytes in suspension, as reported by Brittberg et al., provided a potential procedure for articular cartilage repair. We have improved their procedure and developed a new technique which creates new cartilage-like tissue by cultivating autologous chondrocytes embedded in Atelocollagen gel for 3 weeks before transplantation. These improvements maintained the chondrocyte phenotype, evenly distributed chondrocytes throughout the osteochondral defects, and decreased the risk of leakage of grafted chondrocytes into the defects. Good clinical results suggest that this technique should be a promising procedure for repairing articular cartilage defect.     

A Pre-Clinical Test Platform for the Functional Evaluation of Scaffolds for Musculoskeletal Defects: The Meniscus

In an attempt to delay the progression of osteoarthritis from an index injury, early intervention via repair of injured musculoskeletal soft tissue has been advocated. Despite the development of a number of scaffolds intended to treat soft tissue defects, information about their functional performance is lacking. The goal of this study was to consolidate a suite of in vitro and in vivo models into a pre-clinical test platform to assess the functional performance of meniscal repair scaffolds. Our objective was to assess the ability of a scaffold (Actifit™; Orteq, UK) to carry load without detrimentally abrading against articular cartilage. Three test modules were used to assess the functional performance of meniscal repair scaffolds. The first module tested the ability of the scaffold to carry load in an in vitro model designed to measure the change in normal contact stress magnitude on the tibial plateau of cadaveric knees after scaffold implantation. The second module assessed the in vitro frictional coefficient of the scaffold against cartilage to assess the likelihood that the scaffold would destructively abrade against articular cartilage in vivo. The third module consisted of an assessment of functional performance in vivo by measuring the structure and composition of articular cartilage across the tibial plateau 12 months after scaffold implantation in an ovine model. In vitro, the scaffold improved contact mechanics relative to a partly meniscectomized knee suggesting that, in vivo, less damage would be seen in the scaffold implanted knees vs. partly meniscectomized knees. However, there was no significant difference in the condition of articular cartilage between the two groups. Moreover, in spite of the high coefficient of friction between the scaffold and articular cartilage, there was no significant damage in the articular cartilage underneath the scaffold. The discrepancy between the in vitro and in vivo models was likely influenced by the abundant tissue generated within the scaffold and the unexpected tissue that regenerated within the site of the partial meniscectomy. We are currently augmenting our suite of tests so that we can pre-clinically evaluate the functional performance at time zero and as a function of time after implantation.     

Human autologous culture expanded bone marrow mesenchymal cell transplantation for repair of cartilage defects in osteoarthritic knees

OBJECTIVE: There is no widely accepted method to repair articular cartilage defects. Bone marrow mesenchymal cells have the potential to differentiate into bone, cartilage, fat and muscle. Bone marrow mesenchymal cell transplantation is easy to use clinically because cells can be easily obtained and can be multiplied without losing their capacity of differentiation. The objective of this study was to apply these cell transplantations to repair human articular cartilage defects in osteoarthritic knee joints. DESIGN: Twenty-four knees of 24 patients with knee osteoarthritis (OA) who underwent a high tibial osteotomy comprised the study group. Adherent cells in bone marrow aspirates were culture expanded, embedded in collagen gel, transplanted into the articular cartilage defect in the medial femoral condyle and covered with autologous periosteum at the time of 12 high tibial osteotomies. The other 12 subjects served as cell-free controls. RESULTS: In the cell-transplanted group, as early as 6.3 weeks after transplantation the defects were covered with white to pink soft tissue, in which metachromasia was partially observed. Forty-two weeks after transplantation, the defects were covered with white soft tissue, in which metachromasia was observed in almost all areas of the sampled tissue and hyaline cartilage-like tissue was partially observed. Although the clinical improvement was not significantly different, the arthroscopic and histological grading score was better in the cell-transplanted group than in the cell-free control group. CONCLUSIONS: This procedure highlights the availability of autologous culture expanded bone marrow mesenchymal cell transplantation for the repair of articular cartilage defects in humans.     

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.     

Treatment of a Focal Articular Cartilage Defect of the Talus with Polymer-Based Autologous Chondrocyte Implantation: A 12-Year Follow-Up Period

Autologous chondrocyte implantation (ACI) is a first-line treatment option for large articular cartilage defects. Although well-established for cartilage defects in the knee, studies of the long-term outcomes of matrix-assisted ACI to treat cartilage defects in the ankle are rare. In the present report, we describe for the first time the long-term clinical and radiologic results 12 years after polymer-based matrix-assisted ACI treat a full-thickness talar cartilage defect in a 25-year-old male patient. The clinical outcome was assessed using the visual analog scale and Freiburg ankle score, magnetic resonance imaging evaluation using the Henderson-Kreuz scoring system and T2 mapping. Clinical assessment revealed improved visual analog scale and Freiburg ankle scores. The radiologic analysis and T2 relaxation time values indicated the formation of hyaline-like repair tissue. Polymer-based autologous chondrocytes has been shown to be a safe and clinically effective long-term treatment of articular cartilage defects in the talus.     

膝关节软骨损伤的外科治疗进展

关节软骨损伤后,软骨缺损通常缺乏自行修复能力,要求外科修复。传统外科治疗软骨损伤包括关节镜下冲洗清理术、微骨折术、自体骨软骨移植术、异体骨软骨移植术和自体软骨细胞移植等方法。关节冲洗清理术去除了关节内致痛因素,操作简单,应用广泛,早期疗效确切。微骨折术及自体骨软骨移植对小面积的软骨缺损修复较为理想,然而远期临床观察发现钻孔渗透修复的纤维软骨会降低微骨折术后疗效,相对于重建负重区关节面完整性自体骨软骨移植更具有优势。自体软骨细胞移植及异体骨软骨移植适用于更大面积的软骨缺损,异体骨软骨移植术后存活率受到局部排斥反应影响,从而降低了远期疗效。软骨组织工程技术可最大限度地提高自体软骨细胞移植的修复质量,实现修复组织接近透明软骨,但对于累及软骨下骨板、反应性骨水肿、严重骨量丢失或下肢轴线不良具有局限性。近年来许多新技术陆续应用于软骨损伤治疗领域,创伤小、操作简便、恢复快、疗效好、花费低、多技术联合应用的外科修复技术将会成为未来的治疗软骨损伤的重要手段。目前如何提高软骨修复质量,更具抗压、耐磨性,仍亟待解决。     

Restoration of arthritic cartilage defects using autologous chondrocytes transplantation is superior to cartilage-paste graft in rabbits

This study compared the articular cartilage repair potential of cultured chondrocytes transplantation with bone-cartilage paste-graft in the resurfacing of full-thickness defects without breaching of the subchondral bone plate in rabbit knees. A 5 x 5-mm articular cartilage defect was created in the patellar groove of the femur. Three months following creation, the defect was filled with cultured autologous chondrocytes (group 1) or bone-cartilage paste (group 2). A control group of untreated defects was followed for 1 year. The reparative tissue was analyzed macroscopically, histologically, and by immunohistochemistry 3-12 months post-transplantation. The surfaces of the reparative tissue in group 1 were smooth, and the defects were filled with reparative tissue that resembled hyaline cartilage. The composition of the repair tissue more closely resembled cartilage, as demonstrated by cartilage-specific stains. In contrast, the reparative tissue in group 2 was fibrous and exhibited markers of mesenchymal stem cells and bone formation. Transplantation of cultured chondrocytes into a full-thickness defect in the rabbit generates a biologic substitute tissue that resembles native articular cartilage with living cells capable of synthesizing the surrounding cartilage matrix. In contrast, analysis of the healing response to the paste-graft technique failed to show cartilage-like characteristics. This information may be clinically applicable to direct the use of these treatments in chondral injuries.     

Comparison of MRI and arthroscopy in modified MOCART scoring system after autologous chondrocyte implantation for osteochondral lesion of the talus

Magnetic resonance imaging (MRI) and arthroscopy have frequently been used to evaluate articular cartilage. Many studies have compared the accuracy of MRI to that of arthroscopy. However, there have been no previous comparison studies between MRI and arthroscopy in the evaluation of repaired cartilage after autologous chondrocyte implantation using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system. The purpose of this study was to compare the results between MRI and arthroscopy after autologous chondrocyte implantation of an osteochondral lesion of the talus using a modified MOCART scoring system. Our study investigated 27 consecutive cases in 26 patients who underwent follow-up MRI and second-look arthroscopy 1 year following autologous chondrocyte implantation based on their osteochondral lesion of the talus diagnosis. According to the comparison results of those 5 categories, the agreement between MRI and arthroscopy evaluation results was statistically significant with good reliability in the categories of the degree of defect repair and defect filling, the quality of repaired tissue surface, and synovitis. However, the integration with the border zone and the adhesion category showed poor to moderate reliability. There has been no well-established correlation method between arthroscopy and MRI after autologous chondrocyte implantation of an osteochondral lesion of the talus.