Time course evaluation of reparative cartilage with MR imaging after autologous chondrocyte implantation

The aim of this study was to evaluate the qualitative change in reparative cartilage after autologous chondrocyte implantation (ACI). Ten knees of 10 patients were studied. The signal intensities of reparative and normal cartilage were evaluated by fat-suppressed three-dimensional spoiled-gradient recalled (FS 3D-SPGR) MR imaging. The signal intensity (SI) index (signal intensity of reparative cartilage divided by that of normal cartilage) was defined and the change in SI index was investigated. Histological and biochemical evaluation was done at the second look arthroscopy. The SI index was at its lowest level immediately after ACI and increased with time to 9 months thereafter. After 9-12 months, the SI index settled to almost level and was maintained at that value for at least 2-3 years postoperatively. The average of the SI indexes after 12 months to the last examination was 74.2 +/- 4.6 (range 64.2-82.8), which means signal intensity of reparative cartilage was maintained at a value lower than that of normal cartilage. The total ICRS score was 11.6 +/- 2.3 points (mean +/- SD). The GAG concentration was 107.9 +/- 17.0 microg/mg (mean +/- SD) in normal cartilage and 65.9 +/- 9.4 microg/mg in reparative cartilage. The quality of reparative cartilage as hyaline cartilage was inferior to that of normal cartilage. In the present study, the time course change in the SI index indicates that the major maturation process of implanted chondrocytes neared completion in 9-12 months. Minor changes, such as matrix remodeling with reorganization of the collagen fibers in reparative cartilage, may continue, but an almost identical condition seemed to be maintained during the first 2-3 years of follow-up. SI index does not always reflect all properties of reparative cartilage but may be a useful parameter for noninvasive evaluation.     

Evaluation of reparative cartilage after autologous chondrocyte implantation for osteochondritis dissecans: histology,biochemistry, and MR imaging

Background The aim of this study was to investigate the biochemical properties, histological and immunohistochemical appearance, and magnetic resonance (MR) imaging findings of reparative cartilage after autologous chondrocyte implantation (ACI) for osteochondritis dissecans (OCD). Methods Six patients (mean age 20.2 ± 8.8 years; 13–35 years) who underwent ACI for full-thickness cartilage defects of the femoral condyle were studied. One year after the procedure, a second-look arthroscopic operation was performed with biopsy of reparative tissue. The International Cartilage Repair Society (ICRS) visual histological assessment scale was used for histological assessment. Biopsied tissue was immunohistochemically analyzed with the use of monoclonal antihuman collagen type I and monoclonal antihuman collagen type II primary antibodies. Glycosaminoglycan (GAG) concentrations in biopsied reparative cartilage samples were measured by high performance liquid chromatography (HPLC). MR imaging was performed with T₁- and T₂-weighted imaging and three-dimensional spoiled gradient-recalled (3D-SPGR) MR imaging. Results Four tissue samples were graded as having a mixed morphology of hyaline and fibrocartilage while the other two were graded as fibrocartilage. Average ICRS scores for each criterion were (I) 1.0 ± 1.5; (II) 1.7 ± 0.5; (III) 0.6 ± 1.0; (IV) 3.0 ± 0.0; (V) 1.8 ± 1.5; and (VI) 2.5 ± 1.2. Average total score was 10.7 ± 2.8. On immunohistochemical analysis, the matrix from deep and middle layers of reparative cartilage stained positive for type II collagen; however, the surface layer did not stain well. The average GAG concentration in reparative cartilage was 76.6 ± 4.2 μg/mg whereas that in normal cartilage was 108 ± 11.2 μg/mg. Common complications observed on 3D-SPGR MR imaging were hypertrophy of grafted periosteum, edema-like signal in bone marrow, and incomplete repair of subchondral bone at the surgical site. Clinically, patients had significant improvements in Lysholm scores. Conclusions In spite of a good clinical course, reparative cartilage after ACI had less GAG concentration and was inferior to healthy hyaline cartilage in histological and immunohistochemical appearance and on MRI findings.     

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.     

同种异体软骨细胞与自体骨髓基质干细胞混合共培养构建软骨皮下移植的可行性研究

背景：软骨组织工程的种子细胞问题是目前研究的热点和难点,如何找到一种既能够避免对自体软骨进行取材又能够达到稳定软骨构建目的的方法呢？本研究尝试利用少量同种异体羊软骨细胞作为软骨诱导微环境提供者,与扩增后的羊自体BMSC混合共培养并植入皮下环境,探讨利用同种异体软骨细胞共培养构建软骨皮下移植的可行性。方法：本实验对山羊软骨细胞和BMSC分别进行取材和分离培养扩增,并将以上细胞分为以下四组进行混合并接种在PGA支架材料上：A组：100%自体软骨细胞;B组：30%自体软骨细胞＋70%自体BMSCs;C组：30%同种异体软骨细胞＋70%自体BMSCs;D组：100%同种异体软骨细胞。经过体外构建6周后植入羊皮下进行体内构建12周,对所形成的组织块进行大体观察和组织学染色等评价。结果：自体软骨细胞组和自体软骨细胞混合自体BMSC组皮下移植后可见成熟软骨组织形成,但同种异体软骨细胞参与的两组（包括同种异体软骨细胞混合自体BMSC的实验组和单纯异体软骨细胞组）在皮下环境中都因为较强的免疫反应未能形成软骨组织。结论：同种异体软骨细胞以及PGA支架材料的存在对于组织工程软骨在羊皮下环境的构建有负面影响。     

Arthroscopic autologous chondrocyte implantation for the treatment of a chondral defect in the tibial plateau of the knee

The matrix-induced autologous chondrocyte implantation (MACI; Verigen, Leverküsen, Germany) is a tissue engineering technique for the treatment of deep chondral lesions. Cultured chondrocytes are seeded on a collagen membrane that can be implanted into the defect using exclusively fibrin glue. These features imply some surgical advantages with respect to the traditional ACI technique, such as the possibility of performing the procedure in articular sites, in which putting stitches for the periosteal patch is impossible. We report on the arthroscopic MACI technique for the treatment of a chondral defect of the knee. A 25-year-old man suffered persistent pain at the left knee after a violent direct trauma. Magnetic resonance imaging (MRI) and arthroscopic examination at the time of cartilage biopsy revealed a 2-cm² chondral lesion in the posterior portion of the lateral tibial plateau. The implantation procedure was performed through traditional arthroscopic portals, and the seeded membrane was fixed with fibrin glue, excluding water flow temporarily. Implant stability was verified intraoperatively, and filling of the defect was shown 12 months after surgery by MRI, which showed a hyaline-like cartilage signal. In this specific case, the arthroscopic approach allowed to achieve an optimal view of the lesion, without sacrificing any tendinous or ligamentous structure of the knee.     

Autologous chondrocyte implantation in a canine model: change in composition of reparative tissue with time.

The objective of the study was to evaluate the tissue types filling 4-mm diameter defects in the canine trochlear groove 1.5, 3, and 6 months after autologous chondrocyte implantation (ACI). Untreated defects served as controls. Periosteum alone controls were also included at the 1.5-month time period. The results were compared with previously published findings obtained 12 and 18 months postoperative. After 3 months the ACI-treated defects contained significantly more reparative tissue than found in the untreated control group, including twice the amount of hyaline cartilage (HC). These findings, however, were the only significant effects of the ACI treatment when compared to the periosteum alone or empty control groups. The benefits of ACI found at 3 months did not persist to longer time periods. An evaluation of the inter-observer error associated with the histomorphometric method indicated that it was generally less than the inter-animal variation in the results.     

Repair of human articular cartilage after implantation of autologous chondrocytes

Tissue engineering is an increasingly popular method of addressing pathological disorders of cartilage. Recent studies have demonstrated its clinical efficacy, but there is little information on the structural organisation and biochemical composition of the repair tissue and its relation to the adjacent normal tissue. We therefore analysed by polarised light microscopy and immunohistochemistry biopsies of repair tissue which had been taken 12 months after implantation of autologous chondrocytes in two patients with defects of articular cartilage. Our findings showed zonal heterogeneity throughout the repair tissue. The deeper zone resembled hyaline-like articular cartilage whereas the upper zone was more fibrocartilaginous. The results indicate that within 12 months autologous chondrocyte implantation successfully produces replacement cartilage tissue, a major part of which resembles normal hyaline cartilage.     

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.     

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.     

First successful autologous chondrocyte implantation in Pakistan

Osteochondritis dissecans entails a hyaline cartilage defect of the articular surface causing pain and functional restriction in young adults, sometimes resulting in early degenerative arthritis. Conventional treatment methods such as abrasion chondroplasty and mosaicplasty have limitations in terms of quality of the resultant cartilage and donor site morbidity. A more recent technique, autologous chondrocyte implantation (ACI) results in hyaline cartilage formation and gives good long-term outcome, but requires a high-level cell culture facility and two surgical procedures. The patient was a young female with knee pain, intermittent locking and feeling of "joint mouse". MRI scan and arthroscopy showed a 2 x 2 cm full thickness osteochondral defect in the medial femoral condyle. A free fragment of articular cartilage was found, which was extracted arthroscopically, and chondrocytes were cultured from it in the Juma laboratory. Subsequently, patient underwent surgery whereby the chondrocytes were injected under a periosteal patch sewn over the defect. Over six months, patient's symptoms completely resolved and she returned to full function. A repeat arthroscopy after one year revealed complete filling of the previous defect with normal appearing cartilage indicating success of the procedure. This technology can be utilized for treating patients with a variety of conditions affecting hyaline cartilage of joints.     

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.     

Autologous chondrocyte implantation: a comparison between an open periosteal-covered and an arthroscopic matrix-guided technique

In this prospective study, the authors compared the Carticel method of autologous chondrocyte implantation with the Hyalograft C technique. The aim of the study was to compare the clinical outcomes of the two methods, to identify any complications and to analyse MRI images of the repair process. Seventeen patients who had received autologous chondrocyte implantation with the Carticel technique and ten treated with Hyalograft C were assessed. A statistically significant improvement was observed in both groups at six months (p < 0.001 for Carticel and p = 0.002 for Hyalograft C) and at twelve months after surgery (p < 0.001 both for Carticel and Hyalograft C), according to HSS (Hospital for Special Surgery) and ICRS (International Cartilage Repair Society) scores. There were no statistically significant differences between the two groups. MRI images obtained one year after surgery revealed the formation of well-integrated tissue similar to the surrounding healthy cartilage in most cases, in both Carticel and Hyalograft C groups. Six patients treated with Carticel technique were also assessed by second-look arthroscopy and histology of biopsies. The newly-formed tissue presented structural features similar to normal cartilage in most cases (84%). Molecular analysis was performed to assess mRNA levels of the various collagen molecules and proliferation and differentiation factors: the results showed that the implanted material undergoes progressive remodelling to regenerate hyaline cartilage. Both Carticel and Hyalograft C implantation techniques seem to lead to comparable short- and medium-term results. Moreover, this study confirmed that MRI is a valid tool in the follow-up evaluation of autologous chondrocyte implantation.     

Autologous chondrocyte implantation and osteochondral cylinder transplantation in cartilage repair of the knee joint. A prospective,comparative trial

BACKGROUND: Current methods used to restore the joint surface in patients with localized articular cartilage defects include transplantation of an autologous osteochondral cylinder and implantation of autologous chondrocytes. The purpose of this study was to evaluate the clinical and histological outcomes of these two techniques. METHODS: We performed a prospective clinical study to investigate the two-year outcomes in forty patients with an articular cartilage lesion of the femoral condyle who had been randomly treated with either transplantation of an autologous osteochondral cylinder or implantation of autologous chondrocytes. Biopsy specimens from representative patients of both groups were evaluated with histological staining, immunohistochemistry, and scanning electron microscopy. RESULTS: According to the postoperative Lysholm score, the recovery after autologous chondrocyte implantation was slower than that after osteochondral transplantation at six months (p < or = 0.015), twelve months (p < or = 0.001), and twenty-four months (p < or = 0.012). On the basis of the Meyers score and the Tegner activity score, the results were equally good with the two methods two years after treatment. Histomorphological evaluation of biopsy specimens within two years after autologous chondrocyte implantation demonstrated a complete, mechanically stable resurfacing of the defect in all patients. The tissue consisted mainly of fibrocartilage, while localized areas of hyaline-like regenerative cartilage could be detected close to the subchondral bone. Although a gap remained at the site of the transplantation in all five biopsy specimens examined as long as two years after osteochondral cylinder transplantation, histomorphological analysis and scanning electron microscopy revealed no differences between the osteochondral transplants and the surrounding original cartilage. CONCLUSIONS: Both treatments resulted in a decrease in symptoms. However, the improvement provided by the autologous chondrocyte implantation lagged behind that provided by the osteochondral cylinder transplantation. Histologically, the defects treated with autologous chondrocyte implantation were primarily filled with fibrocartilage, whereas the osteochondral cylinder transplants retained their hyaline character, although there was a persistent interface between the transplant and the surrounding original cartilage. Limitations of our study included the small number of patients, the relatively short (two-year) follow-up, and the absence of a control group.     

Autologous chondrocyte implantation drives early chondrogenesis and organized repair in extensive full‐ and partial‐thickness cartilage defects in an equine model

Autologous chondrocyte implantation (ACI) has been used clinically for over 15 years and yet definitive evidence of chondrocyte persistence and direct impact on cartilage repair in full‐thickness lesions is scant and no data are available on ACI in partial‐thickness defects in any animal model. This study assessed the effect of chondrocytes secured using periosteal overlay in partial‐ and full‐thickness cartilage defects in the equine model. Paired cartilage defects 15 mm in diameter were made in the patellofemoral joint of 16 horse and repaired with ACI or periosteal flap alone. Response was assessed at 8 weeks by clinical, microradiographic, and histologic appearance, and by collagen type II immunohistochemistry, and proteoglycan and DNA quantification. ACI improved histologic scores in partial‐ and full‐thickness cartilage defects, including defect filling, attachment to the underlying subchondral bone, and presence of residual chondrocyte accumulations. For partial‐thickness defects chondrocyte predominance, collagen type II content, and toluidine stained matrix were enhanced, and attachment to the surrounding cartilage improved. DNA and PG content of grafted partial‐thickness defects was improved by chondrocyte implantation. Periosteal patches alone did not induce cartilage repair. This study indicated implantation of chondrocytes to cartilage defects improved healing with a combination of persisting chondrocyte regions, enhanced collagen type II formation, and better overall cartilage healing scores. Use of ACI in the more challenging partial‐thickness defects also improved histologic indices and biochemical content. The equine model of cartilage healing closely resembles cartilage repair in man, and results of this study confirm cell persistence and improved early cartilage healing events after ACI. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1121–1130, 2011     

Articular cartilage restoration in load-bearing osteochondral defects by implantation of autologous chondrocyte-fibrin constructs: an experimental study in sheep

Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded in vitro. Approximately 30 million cells per ml of cultured chondrocytes were incorporated with autologous plasma-derived fibrin to form a three-dimensional construct. Full-thickness punch hole defects were created in the lateral and medial femoral condyles. The defects were implanted with either an autologous 'chondrocyte-fibrin' construct (ACFC), autologous chondrocytes (ACI) or fibrin blanks (AF) as controls. Animals were killed after 12 weeks. The gross appearance of the treated defects was inspected and photographed. The repaired tissues were studied histologically and by scanning electron microscopy analysis. All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O'Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage. Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.     

Injectable cultured bone marrow derived mesenchymal cells vs chondrocytes in the treatment of chondral defects of the knee – RCT with 6 years follow-up

Articular cartilage has unique biological and biomechanical characteristics. Damage to this tissue fails to heal spontaneously, leading to progressive arthritis. Cartilage repair techniques have been looked forward to in the treatment of significant cartilage injuries. Cell-based regenerative techniques like the two-staged cultured chondrocytes and single-stage mesenchymal cell transplantation have been tried with varying results and limitations. We study the outcomes of cultured bone marrow derived MSCs in the treatment of articular cartilage defects of the knee in comparison to autologous cultured chondrocyte implantation (ACI). Both cultured MSC and ACI treatment methods resulted in significant improvements in patient reported outcome measures (PROMs). There was no difference in the PROMs, MOCART scores, T21 mapping and dGEMRIC values between the groups. Use of cultured MSCs leads to good clinical outcomes similar to ACI and represents a promising treatment to restore the articular cartilage in the knee.     

自体软骨细胞移植的临床应用与研究

 目的探讨和研究自体软骨细胞移植技术治疗膝关节软骨缺损的临床效果和临床应用 的可行性。方法 2007年 11月至 2009年 6月, 共 6例膝关节软骨损伤患者。男 2例, 女 4例;年龄 19~ 55岁, 平均 39.5岁;均为膝关节股骨髁关节面软骨缺损, 缺损面积为 3.8~11.6 cm2, 平均 7.3 cm2。利用自 体软骨细胞移植术进行治疗: 关节镜下在膝关节股骨髁间非负重区获取软骨组织 0.2g, 送临床细胞培 养室进行软骨细胞的培养和体外扩增 2~3周;第二次手术, 利用骨膜缝合覆盖, 生物蛋白胶封闭, 将扩 增的软骨细胞悬浮液移植至软骨缺损区;术后进行严格的康复训练。术后定期进行随访, 术前及术后 6、12个月进行 Lysholm主观评分、国际膝关节文献委员会(International Knee Documentation Committee, IKDC)客观等级评定和膝关节 MRI扫描。结果 6例患者均获得随访。术前 Lysholm评分(63.0±8.1)分, 术后 6和 12个月分别为(83.7±10.6)分和(86.3±10.3)分, 获得明显改善;术前 IKDC等级均为 C或 D 级, 术后等级逐步获得改善。术后 6个月和 12个月 MR检查显示所有病例软骨缺损区基本得到修复, 无一例出现术后感染等严重并发症。一例患者由于未能按指导完成康复锻炼, 术后患侧关节疼痛症状 虽有缓解, 但出现粘连, 活动度部分丢失。结论 自体软骨细胞移植治疗膝关节软骨缺损初步疗效基本 满意;术前需严格控制适应证, 术后需高度重视康复锻炼, 以保证手术疗效。     

New Technique for Cell-Seeded Collagen Matrix-Supported Autologous Chondrocyte Transplantation

Autologous chondrocyte transplantation/implantation (ACT/ACI) is becoming increasingly common for the treatment of large cartilage defects in the knee joint. The traditional ACT technique involves injection of a suspension of cells into the cartilage defect, which is covered with a periosteal flap or collagen membrane. The technique requires extensive suturing to create an effective seal; however, cell leakage remains a potential problem. Matrix-induced autologous chondrocyte implantation (MACI/MACT) avoids this potential problem by using a membrane on which chondrocytes are seeded and cultured for several days, before the membrane is cut to the correct size and shape of the defect. Time-consuming extensive suturing is unnecessary. However, cutting and repeated manipulation of the seeded membrane may result in the loss of critical chondrocytes. A modified technique termed ACT-collagen membrane seeding (ACT-Cs) has been developed in which expanded chondrocytes are applied to the collagen membrane after it has been cut to size, substantially reducing the risk of viable cell loss while retaining the ease and speed of the MACI/MACT procedure. In addition, the seeding of mitotically active chondrocytes onto the membrane after expansion and immediately before transplantation allows direct application of high cell concentrations.     

Repair of articular cartilage defects with cultured chondrocytes on polysulphonic membrane: experimental studies in rabbits

INTRODUCTION: Autologous osteochondral transplantation is one method that can be used to create hyaline or hyaline-like repair in a defect area. The purpose of the present study was to repair full-thickness articular cartilage defects in 9 rabbit knee joints with autologous cultured chondrocytes. METHODS: An articular cartilage defect was created on the patellar groove of the femur. The defect was filled with chondrocytes cultured in vitro and placed into the knee on a polysulphonic membrane. At 8 weeks after the operation, the reparative tissue was analyzed macroscopically and histologically. RESULTS: At 8 weeks after the operation, the surfaces of the reparative tissue were smooth, and the defects were filled with mature hyaline cartilage in 5 cases. In 2 cases, the reparative hyaline cartilage was immature and there was worse integration of grafted tissue into the adjacent normal cartilage. In 2 cases, the surface of the grafted area was irregular, and the reparative tissue was disintegrated and incompletely differentiated. CONCLUSION: The results suggest that transplantation of autologous chondrocytes cultured in vitro and placed into the knee on polysulphonic membrane is effective in repairing an articular cartilage defect.     

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.