Matrix-induced autologous chondrocyte implantation for the treatment of chondral defects of the knees in Chinese patients

Microfracture for medium size to large knee chondral defects has limited long-term efficacy: A systematic review

Purpose

To evaluate clinical and radiographic outcomes, return to sport, failure rate, operations and complications in patients undergoing microfracture of the knee, including the femoral condyle, tibial plateau, patella and trochlea, at a mean 10-year or greater follow-up.

Methods

A literature search was performed by querying SCOPUS, PubMed, Medline and the Cochrane Central Register for Controlled Trials from database inception through May 2023 according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Inclusion criteria were level I-IV human studies reporting on outcomes, reoperations and complications following microfracture of the knee at a mean 10-year or greater follow-up. Biomechanical and epidemiological studies, including patients undergoing concomitant realignment procedures, and studies with patients under 18 years old were excluded. Data regarding failure, as defined by each study, as well as reoperations were gathered. Study quality was assessed via the Methodological Index for Nonrandomized Studies criteria.

Results

Nine studies from 2003 to 2018, consisting of 727 patients (mean age 38.9 ± 8.1 years; range 25.8-47.6) undergoing microfracture for chondral defects in the knee were identified. Mean follow-up ranged from 10 to 17 years. Males composed 56.5% of patients, with a mean defect size ranging from 2.3 to 4.01 cm2. Based on radiographs at follow-up, osteoarthritis progression occurred in 40%-48% of patients. Magnetic Resonance Observation of Cartilage Repair Tissue scores were low. Patient-reported outcome measures showed significant improvement in postoperative scores at final follow-up. Return-to-sport rate ranged from 17.2% to 20%. Longitudinal analysis revealed declining clinical outcomes and return-to-sport rates from short- and mid- to long-term follow-up. There was high variability in failure definition and reoperations, with 2.9%-41% of patients requiring total knee arthroplasty.

Conclusions

At a mean 10-year or greater follow-up, microfracture for chondral defects of the knee 2-4 cm2 in size demonstrated a high rate of osteoarthritis progression with poor healing of the chondral defect and low overall return-to-sport rates. Failure and reoperation rates ranged from 2.9% to 41%, with declining outcomes from short- and mid- to long-term follow-up. The advantages of microfracture relating to availability, complexity, and cost should be weighed against concerns about long-term success, particularly with medium-size and larger lesions.

Level of Evidence

Level IV systematic review.

Mid- to Long-Term Clinical Outcomes of Cartilage Restoration of Knee Joint with Allogenic Next-Generation Matrix-Induced Autologous Chondrocyte Implantation (MACI)

OBJECTIVE

Cartilage defect is a common pathology still lacking a unified treating option. The purpose of this retrospective study is to evaluate the safety, efficacy, and clinical and radiological outcome of cartilage restoration of knee joint with allogenic next-generation Matrix-Induced Autologous Chondrocyte Implantation (MACI) for the first time, as well as the correlation between postoperative clinical and radiological outcomes and preoperative patient history and demographics.

METHODS

From July 2014 to August 2020, 15 patients who went through cartilage restoration with allogenic next-generation MACI were included in this study. Patient demographics and PROM including the International Knee Documentation Committee (IKDC) subjective knee score, Lysholm score, Tegner Activity Scale (TAS), and Knee Injury and Osteoarthritis Outcome Score (KOOS) were obtained preoperatively, at 3, 6, 12 months postoperatively and the last follow-up using an online questionnaire platform. MOCART 2.0 score was calculated at the last follow-up. Analysis of variance (ANOVA) was used to compare PROM pre- and post-operation, with two-tailed p < 0.05 defined as statistical significant. Pearson correlation coefficient was used to evaluate correlation between the PROM and MOCART 2.0 score at the last follow-up with patients demorgraphics.

RESULTS

All patients were followed for an average of 66.47 ± 24.15 months (range, 21-93). All patients were satisfied with the outcome of the surgery and no complication was reported at the end of the study. No significant improvement was observed until 1 year after the implantation, except for IKDC score at 6 months. All PROM showed significant improvement 1 year post-op except for Lysholm score and TAS, which also increased significantly at the time of the last follow-up. Pearson correlation coefficient showed that the size of the defect, before or after debridement, was significantly negatively correlated with final KOOS-Pain (before debridement: r = -0.57, p < 0.05; after debridement: r = -0.54, p < 0.05) and KOOS-Symptoms score (before debridement: r = -0.66, p < 0.05; after debridement: r = -0.67, p < 0.05). The MOCART 2.0 score was found significantly and negatively correlated with BMI (r = -0.60, p < 0.05), and significantly and positively correlated with Lysholm score (r = 0.70, p < 0.05).

CONCLUSION

The next generation MACI with autologous chondrocyte and allogenic chondrocyte ECM scaffold could be used to treat focal articular cartilage defect in the knee joint safely and efficiently with lasting promising outcomes for more than 5 years. The size of the defects should be considered the most negatively correlated parameters influencing the postoperative clinical outcomes.

Methodological Flaws in Meta-Analyses of Clinical Studies on the Management of Knee Osteoarthritis with Stem Cells: A Systematic Review

(1) Background: Conclusions of meta-analyses of clinical studies may substantially influence opinions of prospective patients and stakeholders in healthcare. Nineteen meta-analyses of clinical studies on the management of primary knee osteoarthritis (pkOA) with stem cells, published between January 2020 and July 2021, came to inconsistent conclusions regarding the efficacy of this treatment modality. It is possible that a separate meta-analysis based on an independent, systematic assessment of clinical studies on the management of pkOA with stem cells may reach a different conclusion. (2) Methods: PubMed, Web of Science, and the Cochrane Library were systematically searched for clinical studies and meta-analyses of clinical studies on the management of pkOA with stem cells. All clinical studies and meta-analyses identified were evaluated in detail, as were all sub-analyses included in the meta-analyses. (3) Results: The inconsistent conclusions regarding the efficacy of treating pkOA with stem cells in the 19 assessed meta-analyses were most probably based on substantial differences in literature search strategies among different authors, misconceptions about meta-analyses themselves, and misconceptions about the comparability of different types of stem cells with regard to their safety and regenerative potential. An independent, systematic review of the literature yielded a total of 183 studies, of which 33 were randomized clinical trials, including a total of 6860 patients with pkOA. However, it was not possible to perform a scientifically sound meta-analysis. (4) Conclusions: Clinicians should interpret the results of the 19 assessed meta-analyses of clinical studies on the management of pkOA with stem cells with caution and should be cautious of the conclusions drawn therein. Clinicians and researchers should strive to participate in FDA and/or EMA reviewed and approved clinical trials to provide clinically and statistically valid efficacy.

Repopulation of decellularised articular cartilage by laser-based matrix engraving

BACKGROUND

In spite of advances in the treatment of cartilage defects using cell and scaffold-based therapeutic strategies, the long-term outcome is still not satisfying since clinical scores decline years after treatment. Scaffold materials currently used in clinical settings have shown limitations in providing suitable biomechanical properties and an authentic and protective environment for regenerative cells. To tackle this problem, we developed a scaffold material based on decellularised human articular cartilage.

METHODS

Human articular cartilage matrix was engraved using a CO₂ laser and treated for decellularisation and glycosaminoglycan removal. Characterisation of the resulting scaffold was performed via mechanical testing, DNA and GAG quantification and in vitro cultivation with adipose-derived stromal cells (ASC). Cell vitality, adhesion and chondrogenic differentiation were assessed. An ectopic, unloaded mouse model was used for the assessment of the in vivo performance of the scaffold in combination with ASC and human as well as bovine chondrocytes. The novel scaffold was compared to a commercial collagen type I/III scaffold.

FINDINGS

Crossed line engravings of the matrix allowed for a most regular and ubiquitous distribution of cells and chemical as well as enzymatic matrix treatment was performed to increase cell adhesion. The biomechanical characteristics of this novel scaffold that we term CartiScaff were found to be superior to those of commercially available materials. Neo-tissue was integrated excellently into the scaffold matrix and new collagen fibres were guided by the laser incisions towards a vertical alignment, a typical feature of native cartilage important for nutrition and biomechanics. In an ectopic, unloaded in vivo model, chondrocytes and mesenchymal stromal cells differentiated within the incisions despite the lack of growth factors and load, indicating a strong chondrogenic microenvironment within the scaffold incisions. Cells, most noticeably bone marrow-derived cells, were able to repopulate the empty chondrocyte lacunae inside the scaffold matrix.

INTERPRETATION

Due to the better load-bearing, its chondrogenic effect and the ability to guide matrix-deposition, CartiScaff is a promising biomaterial to accelerate rehabilitation and to improve long term clinical success of cartilage defect treatment.

FUNDING

Austrian Research Promotion Agency FFG ("CartiScaff" #842455), Lorenz Böhler Fonds (16/13), City of Vienna Competence Team Project Signaltissue (MA23, #18-08).

Repopulation of decellularised articular cartilage by laser-based matrix engraving

Background

In spite of advances in the treatment of cartilage defects using cell and scaffold-based therapeutic strategies, the long-term outcome is still not satisfying since clinical scores decline years after treatment. Scaffold materials currently used in clinical settings have shown limitations in providing suitable biomechanical properties and an authentic and protective environment for regenerative cells. To tackle this problem, we developed a scaffold material based on decellularised human articular cartilage.

Methods

Human articular cartilage matrix was engraved using a CO₂ laser and treated for decellularisation and glycosaminoglycan removal. Characterisation of the resulting scaffold was performed via mechanical testing, DNA and GAG quantification and in vitro cultivation with adipose-derived stromal cells (ASC). Cell vitality, adhesion and chondrogenic differentiation were assessed. An ectopic, unloaded mouse model was used for the assessment of the in vivo performance of the scaffold in combination with ASC and human as well as bovine chondrocytes. The novel scaffold was compared to a commercial collagen type I/III scaffold.

Findings

Crossed line engravings of the matrix allowed for a most regular and ubiquitous distribution of cells and chemical as well as enzymatic matrix treatment was performed to increase cell adhesion. The biomechanical characteristics of this novel scaffold that we term CartiScaff were found to be superior to those of commercially available materials. Neo-tissue was integrated excellently into the scaffold matrix and new collagen fibres were guided by the laser incisions towards a vertical alignment, a typical feature of native cartilage important for nutrition and biomechanics. In an ectopic, unloaded in vivo model, chondrocytes and mesenchymal stromal cells differentiated within the incisions despite the lack of growth factors and load, indicating a strong chondrogenic microenvironment within the scaffold incisions. Cells, most noticeably bone marrow-derived cells, were able to repopulate the empty chondrocyte lacunae inside the scaffold matrix.

Interpretation

Due to the better load-bearing, its chondrogenic effect and the ability to guide matrix-deposition, CartiScaff is a promising biomaterial to accelerate rehabilitation and to improve long term clinical success of cartilage defect treatment.

Funding

Austrian Research Promotion Agency FFG (“CartiScaff” #842455), Lorenz Böhler Fonds (16/13), City of Vienna Competence Team Project Signaltissue (MA23, #18-08)

Collagen: quantification, biomechanics, and role of minor subtypes in cartilage

Collagen is a ubiquitous biomaterial in vertebrate animals. Although each of its 28 subtypes contributes to the functions of many different tissues in the body, most studies on collagen or collagenous tissues have focussed on only one or two subtypes. With recent developments in analytical chemistry, especially mass spectrometry, significant advances have been made toward quantifying the different collagen subtypes in various tissues; however, high-throughput and low-cost methods for collagen subtype quantification do not yet exist. In this Review, we introduce the roles of collagen subtypes and crosslinks, and describe modern assays that enable a deep understanding of tissue physiology and disease states. Using cartilage as a model tissue, we describe the roles of major and minor collagen subtypes in detail; discuss known and unknown structure-function relationships; and show how tissue engineers may harness the functional characteristics of collagen to engineer robust neotissues.

Collagen Type I: A Versatile Biomaterial

Collagen type I is the most abundant matrix protein in the human body and is highly demanded in tissue engineering, regenerative medicine, and pharmaceutical applications. To meet the uprising demand in biomedical applications, collagen type I has been isolated from mammalians (bovine, porcine, goat and rat) and non-mammalians (fish, amphibian, and sea plant) source using various extraction techniques. Recent advancement enables fabrication of collagen scaffolds in multiple forms such as film, sponge, and hydrogel, with or without other biomaterials. The scaffolds are extensively used to develop tissue substitutes in regenerating or repairing diseased or damaged tissues. The 3D scaffolds are also used to develop in vitro model and as a vehicle for delivering drugs or active compounds.

Morphological, genetic and phenotypic comparison between human articular chondrocytes and cultured chondrocytes

Articular cartilage is an avascular and aneural tissue with limited capacity for regeneration. On large articular lesions, it is recommended to use regenerative medicine strategies, like autologous chondrocyte implantation. There is a concern about morphological changes that chondrocytes suffer once they have been isolated and cultured. Due to the fact that there is little evidence that compares articular cartilage chondrocytes with cultured chondrocytes, in this research we proposed to obtain chondrocytes from human articular cartilage, compare them with themselves once they have been cultured and characterize them through genetic, phenotypic and morphological analysis. Knee articular cartilage samples of 10 mm were obtained, and each sample was divided into two fragments; a portion was used to determine gene expression, and from the other portion, chondrocytes were obtained by enzymatic disaggregation, in order to be cultured and expanded in vitro. Subsequently, morphological, genetic and phenotypic characteristics were compared between in situ (articular cartilage) and cultured chondrocytes. Obtained cultured chondrocytes were rounded in shape, possessing a large nucleus with condensed chromatin and a clear cytoplasm; histological appearance was quite similar to typical chondrocyte. The expression levels of COL2A1 and COL10A1 genes were higher in cultured chondrocytes than in situ chondrocytes; moreover, the expression of COL1A1 was almost undetectable on cultured chondrocytes; likewise, COL2 and SOX9 proteins were detected by immunofluorescence. We concluded that chondrocytes derived from adult human cartilage cultured for 21 days do not tend to dedifferentiate, maintaining their capacity to produce matrix and also retaining their synthesis capacity and morphology.

Patients Scheduled for Chondrocyte Implantation Treatment with MACI Have Larger Defects than Those Enrolled in Clinical Trials

OBJECTIVE

To compare characteristics for patients scheduled for autologous chondrocyte implantation with matrix-assisted chondrocyte implantation (MACI) with those enrolled in clinical trials and to describe differences in patient selection between countries.

DESIGN

Anonymized data from patients scheduled for MACI treatment in the knee in Europe and Australia/Asia were obtained from the Genzyme/Sanofi database. Average age, defect size, and male-female ratio were analyzed and compared by country. Clinical cohort studies and prospective comparative trials using autologous chondrocyte implantation and related treatments were identified and weighted average age, weighted defect size, and male-female ratio were analyzed and compared with data from the database.

RESULTS

From the database 2,690 patients were included with mean age 33.7 years and male-female ratio of 67:33. Mean defect size was 5.64 cm(2) and 70% of the defects were 3 to 10 cm(2). There were significant differences between patients' mean defect sizes between countries. Sixty-nine studies (57 cohorts and 12 prospective comparative trials) with a total of 5,449 patients were identified. The combined weighted mean age was 34.2 years, and the combined weighted mean defect size was 4.89 cm(2). Patients scheduled for MACI had significantly larger defects that those included in clinical trials. There was no significant difference in age. No differences were found between cohorts and prospective comparative trials.

CONCLUSION

The vast majority of patients scheduled for autologous chondrocyte implantation with MACI have chondral defect comparable to that generally recommended, but differences exist between countries. Patients enrolled in clinical trials have significantly smaller defects than those undergoing treatment outside controlled trials.