Repair of porcine articular cartilage defect with autologous chondrocyte transplantation.

Articular cartilage is known to have poor healing capacity after injury. Autologous chondral grafting remains the mainstay to treat well-defined, full-thickness, symptomatic cartilage defects. We demonstrated the utilization of gelatin microbeads to deliver autologous chondrocytes for in vivo cartilage generation. Chondrocytes were harvested from the left forelimbs of 12 Lee-Sung pigs. The cells were expanded in monolayer culture and then seeded onto gelatin microbeads or left in monolayer. Shortly before implantation, the cell-laden beads were mixed with collagen type I gel, while the cells in monolayer culture were collected and re-suspended in culture medium. Full-thickness cartilage defects were surgically created in the weight-bearing surface of the femoral condyles of both knees, covered by periosteal patches taken from proximal tibia, and sealed with a porcine fibrin glue. In total, 48 condyles were equally allotted to experimental, control, and null groups that were filled beneath the patch with chondrocyte-laden beads in gel, chondrocytes in plain medium solution, or nothing, respectively. The repair was examined 6 months post-surgery on the basis of macroscopic appearance, histological scores based on the International Cartilage Repair Society Scale, and the proportion of characteristic chondrocytes. Tensile stress-relaxation behavior was determined from uniaxial indentation tests. The experimental group scored higher than the control group in the categories of matrix nature, cell distribution pattern, and absence of mineralization, with similar surface smoothness. Both the experimental and control groups were superior to the null group in the above-mentioned categories. Viable cell populations were equal in all groups, but the proportion of characteristic chondrocytes was highest in the experimental group. Matrix stiffness was ranked as null > native cartilage > control > experimental group. Transplanted autologous chondrocytes survive and could yield hyaline-like cartilage. The application of beads and gel for transplantation helped to retain the transferred cells in situ and maintain a better chondrocyte phenotype.     

Surgical management of large talar osteochondral defects using autologous chondrocyte implantation

Background

Talar osteochondral lesions (OLT) occur frequently in ankle sprains and fractures. We hypothesize that matrix-induced autologous chondrocyte implantation (MACI) will have a low reoperation rate and high patient satisfaction rate in treating OLT less than 2.5 cm².

Classification of graft hypertrophy after autologous chondrocyte implantation of full-thickness chondral defects in the knee

OBJECTIVE: Graft hypertrophy is a major complication seen in autologous chondrocyte implantation (ACI) with a periosteal flap. We present the first magnetic resonance imaging (MRI) classification for periosteal hypertrophy including a grading of clinical symptoms and the surgical consequences. METHODS: One hundred and two patients with isolated chondral defects underwent an ACI covered with periosteum and were evaluated preoperatively, 6, 18 and 36 months after surgery. Exclusion criteria were meniscal pathologies, axial malpositioning and ligament instabilities. Baseline clinical scores were compared with follow-up data by paired Wilcoxon-tests for the modified Cincinnati knee, the ICRS (International Cartilage Repair Society) and a new MRI score including the parameters defect filling, subchondral edema, effusion, cartilage signal and graft hypertrophy. Hypertrophic changes were graded from 1 (minimal) to 4 (severe). RESULTS: All scores showed significant improvement (P<0.001) over the entire study period. Patients with femoral lesions had significantly better results than patients with patella lesions after 18 and 36 months postoperative (P<0.03). Periosteal hypertrophy occurred in 28% of all patients. Fifty percent of all patella implants developed hypertrophic changes. No patient with grade 1, and all patients with grade 4 hypertrophy had to undergo revision surgery. The Pearson correlation between graft hypertrophy and ICRS score was 0.78 after 6 months, and 0.69 after 36 months (P<0.01). Inclusion of graft hypertrophy in the MRI score improves the correlation to clinical scores from 0.6 to 0.69. CONCLUSIONS: Grading graft hypertrophy helps to identify patients needing an early shaving of the graft. Its integration into an MRI score improves correlation with clinical scores. Re-operation depends on the grade of hypertrophy and clinical symptoms.     

Comparison of articular and auricular cartilage as a cell source for the autologous chondrocyte implantation

Articular (medial femoral condyle) and auricular cartilage (anithelix) was compared as a cell source for the autologous joint repair. Cells isolated from five human cadaveric donors were cultured parallel in the monolayer cultures and in the 3D alginate hydrogel constructs for 1 week. Cell morphology was controlled by the fluorescent microscopy and gene expressions of type I collagen (COL1), type II collagen (COL2), aggrecan (AGR), versican (VER), and elastin (ELS) were analyzed by the real‐time polymerase chain reaction. COL1 and ELS, predominant in the phenotype of auricular biopsy, were statistically lower in the articular biopsies. Even though COL2 and AGR decreased in monolayers of both cell sources, the dedifferentiation process affected auricular cells intensely. Cells embedded in the alginate hydrogel directly after the isolation did not exhibit the dedifferentiated phenotype. Additionally, COL1, COL2, AGR, and VER were comparable between the two sources. ELS however, remained higher in the auricular cells regardless of the culture type. The study indicates that auricular chondrocytes cultured in a 3D environment immediately after the isolation have a neo‐cartilage potential for the articular surface reconstruction. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 943–948, 2009     

Long-term clinical results and MRI changes after autologous chondrocyte implantation in the knee of young and active middle aged patients

Background

Autologous chondrocyte implantation (ACI) represents a valid surgical option for symptomatic full-thickness chondral lesions of the knee. Here we report long-term clinical and MRI results of first-generation ACI.

Materials and methods

Fifteen patients (mean age 21.3 years) underwent first-generation ACI for symptomatic chondral defects of the knee between 1997 and 2001. The mean size of the lesions was 5.08 cm² (range 2–9 cm²). Patients were evaluated using the International Knee Documentation Committee (IKDC) Knee Examination Form, the Tegner Activity Scale, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). High-resolution MRI was used to analyze the repair tissue with nine variables (the MOCART scoring system).

Results

The mean follow-up period was 148 months (range 125–177 months). ACI resulted in substantial improvements in all clinical outcome parameters, even as much as 12 years after implantation. A significant decrease in the MOCART score was recorded at final measurement. Reoperation was required in 2 patients; failure was caused by partial detachment of the graft in both cases.

Conclusion

Autologous chondrocyte implantation is an effective and durable solution for the treatment of large, full-thickness cartilage and osteochondral lesions, even in young and active middle-aged patients. High-resolution MRI is a useful and noninvasive method for evaluating the repaired tissue.

Level of evidence

IV.

     

Long-term follow-up evaluation of autologous chondrocyte implantation for symptomatic cartilage lesions of the knee: A single-centre prospective study

IntroductionAutologous Chondrocyte Implantation (ACI) has been the first technique in reconstruction of a valid articular surface. The aim of this study was to evaluate clinical results of this technique at an average follow up of 162 ± 27 months (range 88–208) in a group of patients who underwent ACI.Materials and methods32 patients were operated between 1997 and 2007 for chondral lesions or osteochondritis dissecans of the knee. Mean size of the defect was 5.48 cm² ± 1.53 (range 2–9). Nine patients were treated with I generation technique and 23 with II generation. All patients were evaluated with Subjective IKDC and Tegner Activity Scales for clinical outcomes and with EQ-VAS for a quantitative measure of health after intervention, starting from pre-operative period and at regular follow up (minimum 88 months-maximum 208 months).ResultsA significant increment of all scores was noticed comparing preoperative and postoperative results. In particular medium IKDC score increased from 40.3 ± 9.6 in preoperative evaluation to 74.2 ± 11.6 at one year (p < 0.00001) and to 83.9 ± 10.4 at 5 years follow up (p < 0.001). Mean IKDC values at the last follow-up were 80.3 ± 14.2, showing no statistical differences with those obtained at five-year follow-up. Tegner Activity Scale values increased from 2.8 ± 1.1 preoperatively to 4.1 ± 1.1 (p < 0.0001) after one year and to 6 ± 1.1 at five years (p < 0.0001). Mean Tegner Activity Scale values decreased to 4.8 ± 1.4 at the last follow-up. EQ-VAS evaluation showed superposable results comparing the 5 years evaluation with the ones at a medium follow up of 162 ± 27 months.DiscussionThe most important finding is the reliability at long-term of ACI technique, which in our series gave excellent clinical results. No statistical differences were observed between first- and second-generation. Clinical outcomes were significantly better for defects in the femoral condyles, influenced by age (worse results over 30 years old).ConclusionsACI represents a valid technique for chondral and osteochondral lesions of the knee in a population heterogeneous for age, sex and activity level with good results even at a long term follow up.     

Autologous chondrocyte implantation for the treatment of retropatellar cartilage defects: clinical results referred to defect localisation

Introduction  Although autologous chondrocyte implantation (ACI) has become well established for the treatment of full-thickness cartilage defects of the knee joint, nevertheless clinical results of retropatellar lesions are still inferior compared to those of defects located on femoral condyles. We report the clinical results obtained in 70 patients treated with ACI for full-thickness defects of the patella, with special reference to defect location and size, age, body mass index and sports activity. Methods  At a follow-up of 38.4 months (range 14–64, follow-up rate 83.3%), patients’ subjective functional knee scores (IKDC, Lysholm) were analysed, as were the results of objective examination (according to ICRS). Results  Mean patient age at the time of surgery was 34.3 years (±10.1). The mean Lysholm score at the time of follow-up was 73.0 (±22.4) and the subjective IKDC score was 61.6 (±21.5); normal and nearly normal clinical results according to the objective criteria of the International Cartilage Research Society (ICRS) were achieved in 67.1% of the patients, while abnormal results were achieved in 20.0% of the patients and severely abnormal results, in 12.9%. While different surgical techniques did not seem to have any significant influence on the treatment results, both defect size and defect location within the patella were found to be significantly associated with clinical outcome. The corollaries to this are that larger cartilage lesions of the patella are associated with an inferior outcome (p = 0.007) and that cartilage defects located on the lateral patellar facet are correlated with a better clinical outcome than those located on the medial facet or those involving both facets (p = 0.017). Conclusion  This study demonstrates that within a group of patients treated with ACI for retropatellar cartilage lesion there are significant differences in clinical outcome, which are important and should be taken into account of when a decision has to be made on whether or not ACI is indicated.     

Cell manipulation in autologous chondrocyte implantation: from research to cleanroom

In the field of orthopaedics, autologous chondrocyte implantation is a technique currently used for the regeneration of damaged articular cartilage. There is evidence of the neo-formation of tissue displaying characteristics similar to hyaline cartilage. In vitro chondrocyte manipulation is a crucial phase of this therapeutic treatment consisting of different steps: cell isolation from a cartilage biopsy, expansion in monolayer culture and growth onto a three-dimensional biomaterial to implant in the damaged area. To minimise the risk of in vitro cell contamination, the manipulation must be performed in a controlled environment such as a cleanroom. Moreover, the choice of reagents and raw material suitable for clinical use in humans and the translation of research protocols into standardised production processes are important. In this study we describe the preliminary results obtained by the development of chondrocyte manipulation protocols (isolation and monolayer expansion) in cleanrooms for the application of autologous implantation.     

关节软骨撞击伤后软骨细胞凋亡的实验研究

[目的]用TUNEL标记法和透射电镜来观察软骨撞击伤后软骨细胞凋亡的演变情况。[方法]56只健康成年新西兰大白兔,随机分高、低能量两组,每组28只,随机选取一侧后肢为实验组,另一侧为对照组;不同重量的击锤撞击股骨内侧髁软骨面致不同的损伤。术后4 d,1、2、4、8、16、32周收集标本,每个时间组4只兔子,进行TUNEL标记法和透射电镜来观察软骨细胞的凋亡。[结果]对照组标本中在软骨的中间层和钙化层,出现凋亡细胞。低能量组中,伤后4 d,1、2周的标本中,软骨的移形层和过渡层出现凋亡细胞,细胞凋亡率与对照组之间无统计学意义;4周后的标本中凋亡细胞明显减少,细胞凋亡率与对照组之间无统计学意义。高能量组中,伤后4 d软骨浅表层和移形层中出现凋亡细胞,而且伤后时间越长凋亡细胞所占比率越大,细胞凋亡率与对照组之间有统计学意义。[结论]软骨高、低能量撞击伤后早期软骨细胞均出现凋亡,凋亡率高于对照组;但低能量伤后4周软骨细胞凋亡率恢复到对照组水平;高能量伤后软骨细胞凋亡率随时间逐渐增高。     

Quantitative analysis of gene expression in human articular chondrocytes assigned for autologous implantation

Autologous chondrocyte implantation (ACI) relies on the implantation of in vitro expanded cells. The aim was to study the dedifferentiation of human articular chondrocytes under different cultivating conditions [days 0–10 in the primary culture (P0); passages in a monolayer from P0 to P3; monolayer vs. alginate and monolayer vs. alginate/agarose hydrogels] using real‐time PCR analysis. The relative gene expressions for collagen type I and II, aggrecan and versican were quantified and the corresponding differentiation indexes (Col2/Col1, Agr/Ver) were calculated. The values of both differentiation indexes decreased exponentially with time in the P0 monolayer culture, and continued with a significant decrease over the subsequent monolayer passages. On the contrary, the chondrocytes seeded in either of the hydrogels significantly increased the indexes compared to their parallel monolayer cultures. These results indicate that alginate and alginate/agarose hydrogels offer an appropriate environment for human articular chondrocytes to redifferentiate after being expanded in vitro. Therefore the three‐dimensional (3D) hydrogel chondrocyte cultures present not only surgical, but also biological advantage over the classic suspension–periosteum chondrocyte implantation. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:847–853, 2008     

The present state of treatments for articular cartilage defects in the knee

INTRODUCTION

Chondral and osteochondral lesions of the knee are notoriously difficult to treat due to the poor healing capacity of articular cartilage and the hostile environment of moving joints, ultimately causing disabling pain and early osteoarthritis. There are many different reconstructive techniques used currently but few are proven to be of value. However, some have been shown to produce a better repair with hyaline-like cartilage rather than fibrocartilage.

METHODS

A systematic search of all available online databases including PubMed, MEDLINE® and Embase™ was undertaken using several keywords. All the multiple treatment options and methods available were considered. These were summarised and the evidence for and against them was scrutinised.

RESULTS

A total of 460 articles were identified after cross-referencing the database searches using the keywords. These revealed that autologous and matrix assisted chondrocyte implantation demonstrated both ‘good to excellent’ histological results and significant improvement in clinical outcomes.

CONCLUSIONS

Autologous and matrix assisted chondrocyte implantation have been shown to treat symptomatic lesions successfully with significant histological and clinical improvement. There is, however, still a need for further randomised clinical trials, perfecting the type of scaffold and the use of adjuncts such as growth factors. A list of recommendations for treatment and the potential future trends of managing these lesions are given.     

Third‐generation autologous chondrocyte implantation versus mosaicplasty for knee cartilage injury: 2‐year randomized trial

Numerous surgical techniques have been developed to treat osteochondral defects of the knee. A study reported encouraging outcomes of third‐generation autologous chondrocyte implantation achieved using the solid agarose‐alginate scaffold Cartipatch®. Whether this scaffold is better than conventional techniques remains unclear. This multicenter randomized controlled trial compared 2‐year functional outcomes (IKDC score) after Cartipatch® versus mosaicplasty in patients with isolated symptomatic femoral chondral defects (ICRS III and IV) measuring 2.5–7.5 cm². In addition, a histological evaluation based on the O'Driscoll score was performed after 2 years. We needed 76 patients to demonstrate an at least 10‐point subjective IKDC score difference with α = 5% and 90% power. During the enrolment period, we were able to include 55 patients, 30 of them were allocated at random to Cartipatch® and 25 to mosaicplasty. After 2 years, eight patients had been lost to follow‐up, six in the Cartipatch® group, and two in the mosaicplasty group. The baseline characteristics of the two groups were not significantly different. The mean IKDC score and score improvement after 2 years were respectively 73.7 ± 20.1 and 31.8 ± 20.8 with Cartipatch® and 81.5 ± 16.4 and 44.4 ± 15.2 with mosaicplasty. The 12.6‐point absolute difference in favor of mosaicplasty is statistically significant. Twelve adverse events were recorded in the Cartipatch® group against six in the mosaicplasty group. After 2 years, functional outcomes were significantly worse after Cartipatch® treatment compared to mosaicplasty for isolated focal osteochondral defects of the femur. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:658–665, 2016.     

自体软骨细胞移植术治疗关节软骨损伤的研究进展

关节软骨再生能力非常有限。目前临床上治疗关节软骨损伤常采用自体软骨细胞移植术(autologous chondrocyte implantation,ACI),其临床效果已得到肯定,但仍不十分理想。随着软骨细胞体外培养、软骨组织工程等相关学科及技术的发展,自体软骨细胞移植术已得到很大改进。然而,要达到理想的透明软骨组织完全修复关节软骨缺损仍有差距。本文从ACI技术的临床效果、软骨细胞体外培养、软骨组织工程、组织学评价和移植后软骨细胞示踪五个方面进行综述。     

自体软骨细胞移植修复猪膝关节软骨缺损的实验研究

目的评价传统和复层高密度培养（复层培养）的自体软骨细胞移植修复关节软骨缺损的效果。方法在8头猪16膝髌切迹上下共建立32个全层软骨缺损，右膝为空白和自体骨膜移植对照组，左膝为传统的自体骨膜覆盖下细胞注射移植组和自体骨膜覆盖下复层培养细胞移植组（上下缺损随机进入各对照和实验组）。术后5-6个月对缺损部位行大体、组织学、免疫组织化学检查。采用O’Driscoll软骨组织形态学评分评价软骨缺损的修复质量。结果四组的O’Driscoll软骨组织形态学评分分别为（3．14±1．95）分、（10．57±3．60）分、（16．29±2．63）分、（20．43±1．81）分，各组之间差异均有统计学意义（P〈0．01）。空白对照组缺损被少量的纤维组织覆盖；骨膜移植组被纤维组织和少量的纤维软骨修复，且与周围组织整合差。自体软骨细胞移植（注射组和复层培养组）缺损被塑形良好的修复组织覆盖，组织学、基质特殊染色示修复组织为纤维软骨和透明软骨，与周边软骨和软骨下骨整合良好。复层培养组修复组织的细胞形态、基质染色比注射细胞组更接近正常软骨。结论自体软骨细胞移植可成功修复全层关节软骨缺损。扩增后的软骨细胞经短期复层培养更有利于软骨缺损的修复。     

An evidence-based update on the management of articular cartilage defects in the hip

ObjectiveArticular cartilage defects in the hip joint pose a significant surgical challenge and remain one of the most important determinants of success following arthroscopic intervention of the hip. The aim of this literature review was to report on the best available evidence on the various treatment options utilised for articular cartilage defects in the hip.Material and methodsA comprehensive literature search was performed on PubMed from its inception to October 2021 using the following search strategy: ((hip) and (cartilage or chondral) and (repair or regeneration or restoration or implantation or chondroplasty or chondrogenic)). Two reviewers (KHSK, MG) independently reviewed titles and abstracts to identify articles for the final analysis. Articles were included if they were original research studies (randomised control trials, cohort studies, case-control studies, or comparative studies) on treatment of hip cartilage defects in humans reporting on a minimum of 5 patients. A total of 1172 articles were identified from the initial literature search. Following a thorough selection process, 35 articles were included in the final analysis to synthesise the evidence.ResultsDebridement, microfracture, autologous chondocyte implanatation (ACI) and matrix-induced ACI (MACI) are shown to have good short-to medium-term results. Injectable ACI and MACI have been developed to enable these procedures to be performed via arthroscopic surgery to reduce the post-operative morbidity associated with surgery with promising early results. Large cartilage defects which involved the sub-chondral bone may need the use of osteochondral grafts either autograft or allograft. Newer biological solutions have been developed to potentially deliver a single-stage procedure for hip cartilage injuries but longer-term results are still awaited.ConclusionAccurate identification of the extent of the injury helps stratify the defect and plan appropriate treatment. Several surgical techniques have shown good short to medium-term outcomes with ACI, AMIC, mosaicplasty and microfracture. Recent advances have enabled the use of injectable MACI and bioscaffolds which show promising results but in the shorter term. However, one needs to be mindful of the techniques which can be used in their surgical setting with the available resources. In order to thoroughly evaluate the benefits of the different surgical techniques for hip cartilage defects, large scale prospective multi-centre studies are necessary. Perhaps inclusion of such procedures in registries may also yield meaningful and pragmatic results.