Matrix-induced autologous chondrocyte implantation (MACI) in the knee

Correlation between the quality of cartilage repair tissue and patellofemoral osteoarthritis after matrix-induced autologous chondrocyte implantation at three-year follow-up: a cross-sectional study

PURPOSE

To investigate whether the quality of cartilage repair tissue is associated with patellofemoral osteoarthritis (PFOA) at a three year follow-up after matrix-induced autologous chondrocyte implantation (MACI).

METHODS

This retrospective study included 32 patients who underwent MACI between October 2014 and May 2018 at our institute. The Lysholm score and Visual Analog Scale (VAS) score were assessed. The magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 score and T2* relaxation time of repair tissue were used to evaluate cartilage repair tissue quality. A modified MRI Osteoarthritis Knee Score (mMOAKS) was used to evaluate PFOA.

RESULTS

Compared with pre-operative scores, the final Lysholm score (50.71 ± 2.22 vs 89.70 ± 1.18; t = 15.5, P < 0.0001) and VAS score (4.67 ± 0.47 vs 0.92 ± 0.64; t = 22.62, P < 0.0001) were improved at 3 years after MACI. At the three year follow-up, the mean MOCART 2.0 score was 61.56 ± 18.11, and the T2* relaxation time of the repair tissue was significantly lower than that in the healthy control region (24.11 ± 6.38 vs 34.39 ± 1.33, t =  - 8.635, P < 0.0001). The mean mMOAKS score was 9.16 ± 4.51. On univariate analysis, the MOCART 2.0 score and T2* relaxation time were negatively associated with the mMOAKS score.

CONCLUSION

MACI can lead to significant pain relief and restoration of knee joint function, and good quality cartilage repair tissue was a protective factor against PFOA at the three year follow-up.

Good healing potential of patellar chondral defects after all-arthroscopic autologous chondrocyte implantation with spheroids: a second-look arthroscopic assessment

PURPOSE

To report second-look arthroscopic assessment after all-arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage defects at the patella.

METHODS

A second-look arthroscopy after all-arthroscopic ACI using chondrospheres^® (ACT3D) was performed in 30 patients with 30 full-thickness retropatellar cartilage defects. The mean time from ACI to second-look arthroscopy was 14.9 ± 16.3 (6-71) months. The quality of cartilage regeneration was evaluated by the International Cartilage-Repair Score (ICRS)-Cartilage Repair Assessment (CRA).

RESULTS

Eleven lesions (36.7%) were classified as CRA grade I (normal) and 19 lesions (63.3%) as grade II (nearly normal). Concerning the degree of defect repair, 25 lesions (83.3%) were repaired up to the height of the surrounding articular retropatellar cartilage. Five lesions (16.7%) showed 75% repair of defect depth. The border zone was completely integrated into the surrounding articular cartilage shoulder in 28 lesions (93.3%) and demarcated within 1 mm in 2 lesions (6.7%). Macroscopically and by probing, 12 lesions (40%) had intact smooth surface, 17 lesions (56.7%) had fibrillated surface and 1 lesion (3.3%) had small, scattered fissures. A negative correlation was found between the overall repair assessment score and the defect size (r² = - 0.430, p = 0.046) and between integration into border zone and defect size (r² = - 0.340, p = 0.045). A positive correlation was found between macroscopic appearance and age (r² =  + 0.384, p = 0.036).

CONCLUSIONS

All-arthroscopic ACI using chondrospheres^® (ACT3D) for full-thickness retropatellar articular cartilage defects proved to be reproducible and reliable. The advantage of the procedure is that it is minimal invasive. Arthroscopic second-look demonstrated a high grade of normal or nearly normal cartilage regeneration. Although statistically significant differences were not observed, larger defect size and younger age may compromise the result of overall repair.

LEVEL OF EVIDENCE

III.

Gelatin methacryloyl as environment for chondrocytes and cell delivery to superficial cartilage defects

Cartilage damage typically starts at its surface, either due to wear or trauma. Treatment of these superficial defects is important in preventing degradation and osteoarthritis. Biomaterials currently used for deep cartilage defects lack appropriate properties for this application. Therefore, we investigated photo‐crosslinked gelatin methacryloyl (gelMA) as a candidate for treatment of surface defects. It allows for liquid application, filling of surface defects and forming a protective layer after UV‐crosslinking, thereby keeping therapeutic cells in place. gelMA and photo‐initiator lithium phenyl‐2,4,6‐trimethyl‐benzoylphosphinate (Li‐TPO) concentration were optimized for application as a carrier to create a favorable environment for human articular chondrocytes (hAC). Primary hAC were used in passages 3 and 5, encapsulated into two different gelMA concentrations (7.5 wt% (soft) and 10 wt% (stiff)) and cultivated for 3 weeks with TGF‐β3 (0, 1 and 10 ng/mL). Higher TGF‐β3 concentrations induced spherical cell morphology independent of gelMA stiffness, while low TGF‐β3 concentrations only induced rounded morphology in stiff gelMA. Gene expression did not vary across gel stiffnesses. As a functional model gelMA was loaded with two different cell types (hAC and/or human adipose‐derived stem cells [ASC/TERT1]) and applied to human osteochondral osteoarthritic plugs. GelMA attached to the cartilage, smoothened the surface and retained cells in place. Resistance against shear forces was tested using a tribometer, simulating normal human gait and revealing maintained cell viability. In conclusion gelMA is a versatile, biocompatible material with good bonding capabilities to cartilage matrix, allowing sealing and smoothening of superficial cartilage defects while simultaneously delivering therapeutic cells for tissue regeneration.

Arthroscopic Matrix-Encapsulated Autologous Chondrocyte Implantation: A Pilot Multicenter Investigation in Latin America

Objective. To evaluate minimum biosecurity parameters (MBP) for arthroscopic matrix-encapsulated autologous chondrocyte implantation (AMECI) based on patients' clinical outcomes, magnetic resonance imaging (MRI) T2-mapping, Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, and International Cartilage Repair Society (ICRS) second-look arthroscopic evaluation, laying the basis for a future multicenter study. Design. Pilot clinical study. We analyzed the logistics to perform AMECI to treat focal chondral lesions in different hospitals following strict biosecurity parameters related to tissue and construct transportation, chondrocyte isolation, and cell expansion. Patient progress was analyzed with patient-reported outcome measures, MRI T2-mapping, MOCART, and ICRS arthroscopic second-look evaluation. Results. Thirty-five lesions in 30 patients treated in 7 different hospitals were evaluated. Cell viability before implantation was >90%. Cell viability in construct remnants was 87% ± 11% at 24 hours, 75% ± 17.1% at 48 hours, and 60% ± 8% at 72 hours after implantation. Mean final follow-up was 37 months (12-72 months). Patients showed statistically significant improvement in all clinical scores and MOCART evaluations. MRI T2-mapping evaluation showed significant decrease in relaxation time from 61.2 ± 14.3 to 42.9 ± 7.2 ms (P < 0.05). Arthroscopic second-look evaluation showed grade II "near normal" tissue in 83% of patients. Two treatment failures were documented. Conclusions. It was feasible to perform AMECI in 7 different institutions in a large metropolitan area following our biosecurity measures without any implant-related complication. Treated patients showed improvement in clinical, MRI T2-mapping, and MOCART scores, as well as a low failure rate and a favorable ICRS arthroscopic evaluation at a mid-term follow-up. Level of Evidence. 2b.

Correlation between the subchondral bone marrow lesions and cartilage repair tissue after matrix-associated autologous chondrocyte implantation in the knee: a cross-sectional study

BACKGROUND

The contribution of the subchondral bone in the development and progression of osteoarthritis (OA) has long been recognized, but its role in cartilage repair procedures has only recently attracted more attention.

PURPOSE

To explore the correlation between the cartilage repair tissue (RT) and the subchondral bone marrow lesions (BMLs) after matrix-associated autologous chondrocyte implantation (MACI) in the knee joint.

MATERIAL AND METHODS

A total of 30 patients who underwent MACI in the knee from January 2015 to June 2018 and follow-up magnetic resonance imaging (MRI) scan were recruited in this study. The MRI results of cartilage RT were evaluated using T2* relaxation time. Subchondral BMLs were also qualitatively evaluated by use of the two-dimensional proton density-weighted fat-suppressed (2D-PD-FS) and three-dimensional dual-echo steady-state (3D-DESS) sequences.

RESULTS

The univariate analysis displayed a significant negative correlation between subchondral BMLs and cartilage RT (P < 0.01). In the minimally adjusted model (only age, sex, and body mass index [BMI] adjusted), the results did not show obvious changes (β = -6.54, 95% confidence interval [CI] = -10.99 to -2.09; P = 0.008). After adjustment for the full models (age, sex, BMI, defect size, combined injury, and preoperative duration of symptoms adjusted), the connection was also detected (β = -6.66, 95% CI -11.82 to -1.50; P = 0.019).

CONCLUSION

After MACI, the subchondral BMLs are significantly correlated with cartilage RT-T₂* relaxation time. The role of subchondral bone in cartilage repair procedures should not be underestimated.

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)

Arthroscopic gel-type autologous chondrocyte implantation presents histologic evidence of regenerating hyaline-like cartilage in the knee with articular cartilage defect

PURPOSE

To investigate the clinical, radiological, and histological results of arthroscopic gel-type autologous chondrocyte implantation (GACI) in treating chondral defects of the knee.

METHODS

This study prospectively examined five males and five females with a mean age of 40.3 ± 10.3 years who underwent arthroscopic GACI between March 2012 and February 2013. The gel comprised a mixture of 1 ml of fibrinogen plus 0.1-0.2 ml of thrombin. The mean size of chondral defect was 2.9 ± 1.2 cm² (range 1.2-5.4 cm²). International knee documentation committee (IKDC) subjective score, knee injury and osteoarthritis outcome score (KOOS), knee society score, and visual analog scale (VAS) for pain were assessed preoperatively and during regular follow-up examinations performed for up to 5 years postoperatively. Serial magnetic resonance imaging was performed for up to 2 years after the surgery to observe healing, using the modified magnetic resonance observation of cartilage repair tissue (MOCART) score. In eight patients, second-look arthroscopy was performed at 1 year after the implantation to assess the status of treated cartilage, and a portion of regenerated cartilage was harvested for histologic evaluation.

RESULTS

The mean VAS score (p = 0.045), IKDC subjective score (p = 0.041), KOOS pain (p = 0.025), KOOS activities of daily living (p = 0.048), and KOOS quality of life (p = 0.029) showed significant improvement at 5 years after the surgery. The modified MOCART evaluation showed that the scores were 59.5 ± 29.4 and 85.0 ± 8.0 at 12 weeks and 2 years after the operation, respectively. Histologic examination demonstrated a mean regenerated cartilage thickness of 3.5 ± 0.8 mm and a mean Oswestry score of 8.2 ± 1.8. Immunohistochemistry analysis showed that the expression of collagen type II was more evident and more evenly distributed than collagen type I in regenerated cartilage. There was a significant correlation between Oswestry score and change in VAS scale from postoperative 2-5 years.

CONCLUSIONS

Arthroscopic GACI produces satisfactory clinical and radiologic outcomes, and histologic evaluation confirms sufficient regeneration of hyaline-like cartilage that correlates with improved symptoms. Therefore, it is an acceptable, minimally invasive, and technically simple option for the restoration of cartilage defects of the knee.

LEVEL OF EVIDENCE

IV.

Autologous Costal Cartilage Graft-A New Method to Treat Articular Cartilage Defects: Case Report and Note of Surgical Technique

Full-thickness articular cartilage defects do not heal spontaneously. Several techniques have been developed to address this issue, but none resulted in the restitutio ad integrum of the articular cartilage. The most frequent sites of chondral lesion in the knee are medial femoral condyle and patella. The patellofemoral lesions are characterized by outcomes that are generally worse than those of tibiofemoral ones. To date, it has been well recognized the chondrogenic potential of rib perichondrium, and costal cartilage grafts have been extensively used in reconstructive surgery. Considering the need to find a gold standard technique to restore articular defect, we developed and here described a new technique to repair cartilage lesions of the knee using autologous costal cartilage graft with its perichondrium. This innovative surgical approach can be used to treat full thickness articular defects using autologous hyaline cartilage, making it possible to cover wide defects. This one step technique is low invasive, not technically demanding with minimal donor site morbidity and it has low costs. The long-term clinical efficacy of the method remains to be evaluated.

Non-Destructive Spectroscopic Assessment of High and Low Weight Bearing Articular Cartilage Correlates with Mechanical Properties

OBJECTIVE

Autologous articular cartilage (AC) harvested for repair procedures of high weight bearing (HWB) regions of the femoral condyles is typically obtained from low weight bearing (LWB) regions, in part due to the lack of non-destructive techniques for cartilage composition assessment. Here, we demonstrate that infrared fiber optic spectroscopy can be used to non-destructively evaluate variations in compositional and mechanical properties of AC across LWB and HWB regions.

DESIGN

AC plugs (N = 72) were harvested from the patellofemoral groove of juvenile bovine stifle joints, a LWB region, and femoral condyles, a HWB region. Near-infrared (NIR) and mid-infrared (MIR) fiber optic spectra were collected from plugs, and indentation tests were performed to determine the short-term and equilibrium moduli, followed by gravimetric water and biochemical analysis.

RESULTS

LWB tissues had a significantly greater amount of water determined by NIR and gravimetric assay. The moduli generally increased in tissues from the patellofemoral groove to the condyles, with HWB condyle cartilage having significantly higher moduli. A greater amount of proteoglycan content was also found in HWB tissues, but no differences in collagen content. In addition, NIR-determined water correlated with short-term modulus and proteoglycan content (R = -0.40 and -0.31, respectively), and a multivariate model with NIR data was able to predict short-term modulus within 15% error.

CONCLUSIONS

The properties of tissues from LWB regions differ from HWB tissues and can be determined non-destructively by infrared fiber optic spectroscopy. Clinicians may be able to use this modality to assess AC prior to harvesting osteochondral grafts for focal defect repair.

Repopulation of an auricular cartilage scaffold, AuriScaff, perforated with an enzyme combination

Biomaterials currently in use for articular cartilage regeneration do not mimic the composition or architecture of hyaline cartilage, leading to the formation of repair tissue with inferior characteristics. In this study we demonstrate the use of "AuriScaff", an enzymatically perforated bovine auricular cartilage scaffold, as a novel biomaterial for repopulation with regenerative cells and for the formation of high-quality hyaline cartilage. AuriScaff features a traversing channel network, generated by selective depletion of elastic fibers, enabling uniform repopulation with therapeutic cells. The complex collagen type II matrix is left intact, as observed by immunohistochemistry, SEM and TEM. The compressive modulus is diminished, but three times higher than in the clinically used collagen type I/III scaffold that served as control. Seeding tests with human articular chondrocytes (hAC) alone and in co-culture with human adipose-derived stromal/stem cells (ASC) confirmed that the network enabled cell migration throughout the scaffold. It also guides collagen alignment along the channels and, due to the generally traverse channel alignment, newly deposited cartilage matrix corresponds with the orientation of collagen within articular cartilage. In an osteochondral plug model, AuriScaff filled the complete defect with compact collagen type II matrix and enabled chondrogenic differentiation inside the channels. Using adult articular chondrocytes from bovine origin (bAC), filling of even deep defects with high-quality hyaline-like cartilage was achieved after 6 weeks in vivo. With its composition and spatial organization, AuriScaff provides an optimal chondrogenic environment for therapeutic cells to treat cartilage defects and is expected to improve long-term outcome by channel-guided repopulation followed by matrix deposition and alignment. STATEMENT OF SIGNIFICANCE: After two decades of tissue engineering for cartilage regeneration, there is still no optimal strategy available to overcome problems such as inconsistent clinical outcome, early and late graft failures. Especially large defects are dependent on biomaterials and their scaffolding, guiding and protective function. Considering the currently used biomaterials, structure and mechanical properties appear to be insufficient to fulfill this task. The novel scaffold developed within this study is the first approach enabling the use of dense cartilage matrix, repopulate it via channels and provide the cells with a compact collagen type II environment. Due to its density, it also provides better mechanical properties than materials currently used in clinics. We therefore think, that the auricular cartilage scaffold (AuriScaff) has a high potential to improve future cartilage regeneration approaches.

Tissue engineering the human auricle by auricular chondrocyte-mesenchymal stem cell co-implantation

Children suffering from microtia have few options for auricular reconstruction. Tissue engineering approaches attempt to replicate the complex anatomy and structure of the ear with autologous cartilage but have been limited by access to clinically accessible cell sources. Here we present a full-scale, patient-based human ear generated by implantation of human auricular chondrocytes and human mesenchymal stem cells in a 1:1 ratio. Additional disc construct surrogates were generated with 1:0, 1:1, and 0:1 combinations of auricular chondrocytes and mesenchymal stem cells. After 3 months in vivo, monocellular auricular chondrocyte discs and 1:1 disc and ear constructs displayed bundled collagen fibers in a perichondrial layer, rich proteoglycan deposition, and elastin fiber network formation similar to native human auricular cartilage, with the protein composition and mechanical stiffness of native tissue. Full ear constructs with a 1:1 cell combination maintained gross ear structure and developed a cartilaginous appearance following implantation. These studies demonstrate the successful engineering of a patient-specific human auricle using exclusively human cell sources without extensive in vitro tissue culture prior to implantation, a critical step towards the clinical application of tissue engineering for auricular reconstruction.

Current Therapeutic Strategies for Stem Cell-Based Cartilage Regeneration

The process of cartilage destruction in the diarthrodial joint is progressive and irreversible. This destruction is extremely difficult to manage and frustrates researchers, clinicians, and patients. Patients often take medication to control their pain. Surgery is usually performed when pain becomes uncontrollable or joint function completely fails. There is an unmet clinical need for a regenerative strategy to treat cartilage defect without surgery due to the lack of a suitable regenerative strategy. Clinicians and scientists have tried to address this using stem cells, which have a regenerative potential in various tissues. Cartilage may be an ideal target for stem cell treatment because it has a notoriously poor regenerative potential. In this review, we describe past, present, and future strategies to regenerate cartilage in patients. Specifically, this review compares a surgical regenerative technique (microfracture) and cell therapy, cell therapy with and without a scaffold, and therapy with nonaggregated and aggregated cells. We also review the chondrogenic potential of cells according to their origin, including autologous chondrocytes, mesenchymal stem cells, and induced pluripotent stem cells.

Matrix-Induced Autologous Chondrocyte Implantation (MACI) Using a Cell-Seeded Collagen Membrane Improves Cartilage Healing in the Equine Model

BACKGROUND

Autologous chondrocyte implantation (ACI) using a collagen scaffold (matrix-induced ACI; MACI) is a next-generation approach to traditional ACI that provides the benefit of autologous cells and guided tissue regeneration using a biocompatible collagen scaffold. The MACI implant also has inherent advantages including surgical implantation via arthroscopy or miniarthrotomy, the elimination of periosteal harvest, and the use of tissue adhesive in lieu of sutures. This study evaluated the efficacy of the MACI implant in an equine full-thickness cartilage defect model at 1 year.

METHODS

Autologous chondrocytes were seeded onto a collagen type-I/III membrane and implanted into one of two 15-mm defects in the femoral trochlear ridge of 24 horses. Control defects either were implanted with cell-free collagen type-I/III membrane (12 horses) or were left ungrafted as empty defects (12 horses). An additional 3 horses had both 15-mm defects remain empty as nonimplanted joints. The repair was scored by second-look arthroscopy (12 weeks), and necropsy examination (53 weeks). Healing was assessed by arthroscopic scoring, gross assessment, histology and immunohistology, cartilage matrix component assay, and gene expression determination. Toxicity was examined by prostaglandin E2 formation in joint fluid, and lymph node morphology combined with histologic screening of organs.

RESULTS

MACI-implanted defects had improved gross healing and composite histologic scores, as well as increases in chondrocyte predominance, toluidine blue-stained matrix, and collagen type-II content compared with scaffold-only implanted or empty defects. There was minimal evidence of reaction to the implant in the synovial membrane (minor perivascular cuffing), subchondral bone, or cartilage. There were no adverse clinical effects, signs of organ toxicity, or evidence of chondrocytes or collagen type-I/III membrane in draining lymph nodes.

CONCLUSIONS

The MACI implant appeared to improve cartilage healing in a critical-sized defect in the equine model compared with collagen matrix alone.

CLINICAL RELEVANCE

These results indicate that the MACI implant is quick to insert, provides chondrocyte security in the defect, and improves cartilage healing compared with ACI.

Construction and biocompatibility of a thin type I/II collagen composite scaffold

Articular cartilage injury is a common type of damage observed in clinical practice. A matrix-induced autologous chondrocyte implant was developed to repair articular cartilage as an advancement on the autologous chondrocyte implant procedure. Here, we establish a thin double layer of collagen as a novel and effective bioscaffold for the regeneration of cartilaginous lesions. We created a collagen membrane with double layers using a cover slip, a cover slip, and the collagen was then freeze-dried under vacuum. Carbodiimide as a crosslinking agent was used to obtain a relatively stable collagen construction. The thickness of the knee joint cartilage from grown rabbits was measured from a frozen section. Both type I and type II collagens were characterized using Sodium dodecylsulfate/polyacrylamide gel electrophoresis (SDS-PAGE) and ultraviolet absorption peaks. The aperture size of the scaffold was observed using a scanning electron microscope (SEM). The degradation of the scaffolds in vitro was tested through digestion using collagenase solution. The mechanical capacity of the scaffolds was assessed under dynamic compression. The influence of the scaffold on chondrocyte proliferation was assessed using the methyl thiazolyl tetrazolium (MTT) colourimetric assay and scanning electron microscopy. The frozen sections of the rabbit femoral condyle showed that the thickness of the weight-bearing area of the articular cartilage was less than 1 mm. The results of the SDS-PAGE and ultraviolet absorption peaks of the collagens were in agreement with the standard photographs in the references. SEM showed that the aperture size of the cross-linked scaffold was 82.14 ± 15.70 μm. The in vitro degradation studies indicated that Carbodiimide cross-linking can effectively enhance the biostability of the scaffolds. The Carbodiimide cross-linking protocol resulted in a mean value for the samples that ranged from 8.72 to 15.95 MPa for the compressive strength. The results of the MTT demonstrated that the scaffold had promoted chondrocyte proliferation and SEM observations showed that the scaffold was a good adhesive and growth material for chondrocytes. Thin type I/II collagen composite scaffold can meet the demands of cartilage tissue engineering and have good biocompatibility.

Peritoneum and omentum are natural reservoirs for chondrocytes of osteochondral autografts: A comparative animal study

Objective

The purpose of this study was to investigate the effects of the omentum, peritoneum, paratenon and skeletal muscle on the proliferation of the cartilage tissue using rabbit model as an in vivo culture medium.

Methods

6 months old forty-five New Zealand rabbits were randomized into omentum, peritoneum, muscle, and Achilles paratenon groups. Standard sized osteochondral grafts were harvested from right knees and immediately placed into the specified tissues. Control group was fresh cartilage at the end of follow-up. After five months, samples were collected and evaluated macroscopically by measuring their dimensions (vertical = D1, horizontal = D2, and depth = D3) and volumes, and histologically by counting the chondrocyte number using camera lucida method.

Results

Macroscopically, increase in mean values for D1 and D2 dimensions of specimens from paratenon and omentum compared to pretransplant dimensions was statistically significant (p < 0.05). Although, volume measurements were higher in omentum and peritoneum group compared to pretransplant dimensions, increase was not significant (p > 0.05). Histologically, mean chondrocyte count was 14.0 ± 0.6 in fresh articular cartilage. Mean chondrocyte counts were 14.4 ± 0.9 in omentum group, 15.4 ± 1.0 in peritoneum group, 9.7 ± 1.3 in muscle group and 9.2 ± 0.4 in Achilles paratenon group respectively. However, mean chondrocyte counts were higher in samples of omentum and peritoneum group compared to fresh articular cartilage, increase was not statistically significant (p > 0.05).

Discussion

Transplantation of the cartilage grafts into mesothelium enhanced the chondrocyte counts and volumes compared with the pretransplant measurements. Mesothelium may have the potential to be used as an in vivo culture medium for osteochondral tissue growth.

Correlation between histological outcome and surgical cartilage repair technique in the knee: A meta-analysis

BACKGROUND

Compare histological outcomes after microfracture (MF), autologous chondrocyte implantation (ACI), and osteochondral autograft transfer (OATS).

METHODS

Literature review using PubMed MEDLINE, SCOPUS, Cumulative Index for Nursing and Allied Health Literature (CINAHL), and Cochrane Collaboration Library. Inclusion criteria limited to English language studies International Cartilage Repair Society (ICRS) grading criteria for cartilage analysis after ACI (autologous chondrocyte implantation), MF (microfracture), or OATS (osteochondral autografting) repair techniques.

RESULTS

Thirty-three studies investigating 1511 patients were identified. Thirty evaluated ACI or one of its subtypes, six evaluated MF, and seven evaluated OATS. There was no evidence of publication bias (Begg's p=0.48). No statistically significant correlation was found between percent change in clinical outcome and percent biopsies showing ICRS Excellent scores (R(2)=0.05, p=0.38). Percent change in clinical outcome and percent of biopsies showing only hyaline cartilage were significantly associated (R(2)=0.24, p=0.024). Mean lesion size and histological outcome were not correlated based either on percent ICRS Excellent (R(2)=0.03, p=0.50) or percent hyaline cartilage only (R(2)=0.01, p=0.67). Most common lesion location and histological outcome were not correlated based either on percent ICRS Excellent (R(2)=0.03, p=0.50) or percent hyaline cartilage only (R(2)=0.01, p=0.67).

CONCLUSIONS

Microfracture has poorer histologic outcomes than other cartilage repair techniques. OATS repairs primarily are comprised of hyaline cartilage, followed closely by cell-based techniques, but no significant difference was found cartilage quality using ICRS grading criteria among OATS, ACI-C, MACI, and ACI-P.

LEVEL OF EVIDENCE

IV, meta-analysis.

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Second-look assessment after all-arthroscopic autologous chondrocyte implantation with spheroides at the knee joint

PURPOSE

To report arthroscopic second look as well as clinical results after arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage repair at the knee joint.

METHODS

A second-look assessment after arthroscopic ACI using spheroides was performed in 41 patients with 57 full-size articular cartilage defects of the knee. The median time from ACI to second-look arthroscopy was 10 (6-72) months. The ACI was assessed macroscopically and by probing according to the International Cartilage Repair Score (ICRS)-Cartilage Repair Assessment (CRA) to get information on the amount and quality of regeneration. Clinical follow-up with subjective outcome scores was performed an average of 34.5 ± 19.2 months after ACI. Twenty-seven (65.8 %) of ACI's were combined with additional procedures.

RESULTS

The ICRS-CRA was rated "normal" or "nearly normal" in 52 of 57 (91.3 %) and "abnormal" in 5 (8.8 %) of all cartilage defects. At follow-up, evaluation of KOOS was an average of 81.0 ± 12.9 for pain, 76.8 ± 16.6 for symptoms, 85.1 ± 14.9 for activities of daily living, 55.3 ± 27.7 for sport and recreation and 50.6 ± 23.8 for quality of live. IKDC was 63.0 ± 18.8, Lysholm score was 79.0 ± 18.0, and Tegner score was 4 (1-6). Subjective assessment according to the VAS scale was an average of 7.4 ± 2.1 for overall satisfaction and 6.7 ± 2.5 satisfaction for the operated knee. Seven patients (22.6 %) showed low subjective outcome scores at last follow-up-of these, 2 patients showed a CRA 3 and 5 a CRA 1 or 2.

CONCLUSION

At second-look arthroscopy, 52 (91.3 %) of all cartilage defects showed a normal or nearly normal macroscopic articular cartilage regeneration after arthroscopic ACI using spheroides. Twenty-four patients (77.4 %) showed good subjective clinical results. The high number of concomitant surgery reflexes the complex aetiology of cartilage lesions and complexity of treatment. Thus, a strict indication and surgical planing is necessary to avoid clinical failures.

LEVEL OF EVIDENCE

IV.

Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Matrix-induced autologous chondrocyte implantation (MACI) in the knee: clinical outcomes and challenges

PURPOSE

Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated effectiveness in treating isolated cartilage defects of the knee but medium- and long-term evidence and information on the management of postoperative complications or partially successful cases are sparse. This study hypothesised that MACI is effective for up to 5 years and that patients with posttreatment problems may go on to obtain clinical benefit from other interventions.

METHODS

A follow-on, prospective case series of patients recruited into a previous controlled, randomised, prospective study or newly enroled. Patients were followed up 6, 12, 24 and 60 months after surgery. Outcome measures were Tegner (activity levels) and Lysholm (pain, stability, gait, clinical symptoms) scores. Zone-specific subgroups were analysed 6, 12 and 24 months postoperatively.

RESULTS

Sixty-five patients were treated with MACI. Median Tegner score improved from II to IV at 12 months; an improvement maintained to 60 months. Mean Lysholm score improved from 28.5 to 76.6 points (±19.8) at 24 months, settling back to 75.5 points after 5 years (p > 0.0001). No significant differences were identified in the zone-specific analysis. Posttreatment issues (N = 12/18.5 %) were resolved with microfracture, debridement, OATS or bone grafting.

CONCLUSIONS

MACI is safe and effective in the majority of patients. Patients in whom treatment is only partially successful can go on to obtain clinical benefit from other cartilage repair options. This study adds to the clinical evidence on the MACI procedure, offers insight into likely treatment outcomes, and highlights MACI's usefulness as part of an armamentarium of surgical approaches to the treatment of isolated knee defects.

LEVEL OF EVIDENCE

Prospective case control study with no control group, Level III.

High Tibial Osteotomy in Combination With Chondrogenesis After Stem Cell Therapy: A Histologic Report of 8 Cases

PURPOSE

To histologically evaluate the quality of articular cartilage regeneration from the medial compartment after arthroscopic subchondral drilling followed by postoperative intra-articular injections of autologous peripheral blood stem cells (PBSCs) and hyaluronic acid with concomitant medial open-wedge high tibial osteotomy (HTO) in patients with varus deformity of the knee joint.

METHODS

Eight patients with varus deformity of the knee joint underwent arthroscopic subchondral drilling of International Cartilage Repair Society (ICRS) grade 4 bone-on-bone lesions of the medial compartment with concomitant HTO. These patients were part of a larger pilot study in which 18 patients underwent the same procedure. PBSCs were harvested and cryopreserved preoperatively. At 1 week after surgery, 8 mL of PBSCs was mixed with 2 mL of hyaluronic acid and injected intra-articularly into the knee joint; this was repeated once a week for 5 consecutive weeks. Three additional intra-articular injections were administered weekly at intervals of 6, 12, and 18 months postoperatively. Informed consent was obtained at the time of hardware removal for opportunistic second-look arthroscopy and chondral biopsy. Biopsy specimens were stained with H&E, safranin O, and immunohistochemical staining for type I and II collagen. Specimens were graded using the 14 components of the ICRS Visual Assessment Scale II, and a total score was obtained.

RESULTS

Second-look arthroscopy showed satisfactory healing of the regenerated cartilage. Histologic analysis showed significant amounts of proteoglycan and type II collagen. The total ICRS Visual Assessment Scale II histologic scores comparing the regenerated articular cartilage (mean, 1,274) with normal articular cartilage (mean, 1,340) indicated that the repair cartilage score approached 95% of the normal articular cartilage score. There were no infections, delayed unions, or nonunions.

CONCLUSIONS

Chondrogenesis with stem cells in combination with medial open-wedge HTO for varus deformity correction of the knee joint regenerates cartilage that closely resembles the native articular cartilage.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

A chondrocyte infiltrated collagen type I/III membrane (MACI® implant) improves cartilage healing in the equine patellofemoral joint model

Autologous chondrocyte implantation (ACI) has improved outcome in long-term studies of joint repair in man. However, ACI requires sutured periosteal flaps to secure the cells, which precludes minimally-invasive implantation, and introduces complications with arthrofibrosis and graft hypertrophy. This study evaluated ACI on a collagen type I/III scaffold (matrix-induced autologous chondrocyte implantation; MACI(®)) in critical sized defects in the equine model.

METHODS

Chondrocytes were isolated from horses, expanded and seeded onto a collagen I/III membrane (ACI-Maix™) and implanted into one of two 15-mm defects in the femoral trochlear ridge of six horses. Control defects remained empty as ungrafted debrided defects. The animals were examined daily, scored by second look arthroscopy at 12 weeks, and necropsy examination 6 months after implantation. Reaction to the implant was determined by lameness, and synovial fluid constituents and synovial membrane histology. Cartilage healing was assessed by arthroscopic scores, gross assessment, repair tissue histology and immunohistochemistry, cartilage glycosaminoglycan (GAG) and DNA assay, and mechanical testing.

RESULTS

MACI(®) implanted defects had improved arthroscopic second-look, gross healing, and composite histologic scores, compared to spontaneously healing empty defects. Cartilage GAG and DNA content in the defects repaired by MACI implant were significantly improved compared to controls. Mechanical properties were improved but remained inferior to normal cartilage. There was minimal evidence of reaction to the implant in the synovial fluid, synovial membrane, subchondral bone, or cartilage.

CONCLUSIONS

The MACI(®) implant appeared to improve cartilage healing in a critical sized defect in the equine model evaluated over 6 months.

Short-term follow up after implantation of a cell-free collagen type I matrix for the treatment of large cartilage defects of the knee

PURPOSE

Although there are various new scaffold-based techniques for cartilage regeneration it remains unclear up to which defect size they can be used. The present study reports of a cell-free collagen type I gel matrix for the treatment of large cartilage defects of the knee after a two-year follow-up.

METHODS

Twenty-eight patients with a mean cartilage defect size of 3.71 ± 1.93 cm² were treated with a cell-free collagen type I gel matrix (CaReS-1S®, Arthro Kinetics AG, Krems/Donau, Austria) via a mini-arthrotomy. Clinical outcome was assessed preoperatively and six weeks as well as six, 12 and 24 months after surgery using various clinical outcome scores (IKDC, Tegner, KOOS, VAS). Cartilage regeneration was evaluated via MRI using the MOCART score.

RESULTS

Seventeen male and 11 female patients with a mean age of 34.6 years were included in this study. Significant pain reduction (VAS) could be noted after six weeks already. Patient activity (IKDC, Tegner) could be significantly improved from 12 months on and nearly reached reported pre-operative values. All subject categories of the KOOS except for symptom (swelling) showed significant improvements throughout the study. Constant significant improvements of the mean MOCART score were observed from 12 months on. MR images did not yield any signs of infection or synovitis. After 24 months a complete defect filling could be noted in 24 out of 28 cases with a mainly smooth surface, complete integration of the border zone and homogenous structure of the repaired tissue.

CONCLUSION

Cell-free collagen type I matrices appear to be a safe and suitable treatment option even for large cartilage defects of the knee. Results of this study were comparable to the better-established findings for small cartilage defects. Mid- and long-term results will be needed to see if clinical and MR-tomographic outcome can be maintained beyond 24 months.

One-step cartilage repair in the knee: collagen-covered microfracture and autologous bone marrow concentrate. A pilot study

BACKGROUND

Different single-stage surgical approaches are currently under evaluation to repair cartilage focal lesions. To date, only little is known on even short-term clinical follow-up and almost no knowledge exists on histological results of such treatments. The present paper aims to analyze the clinical and histological results of the collagen-covered microfracture and bone marrow concentrate (C-CMBMC) technique in the treatment of focal condylar lesions of knee articular cartilage.

METHODS

Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic microfractures (MFX) covered with a collagen membrane immersed in autologous bone marrow concentrate (BMC) from the iliac crest. Patients were retrospectively assessed using several standardized outcome assessment tools and MRI scans. Four patients consented to undergo second look arthroscopy and biopsy harvest.

RESULTS

Every patient was arthroscopically treated for a focal condylar lesion (mean area 2.5 SD(0.4) cm(2)). All the patients (mean age 43 SD(9) years) but one experienced a significant clinical improvement from the pre-operative condition to the latest follow-up (mean 29 SD(11) months). Cartilage macroscopic assessment at 12 months revealed that all the repairs appeared almost normal. Histological analysis showed a hyaline-like cartilage repair in one lesion, a fibrocartilaginous repair in two lesions and a mixture of both in one lesion.

CONCLUSIONS

The first clinical experience with single-stage C-CMBMC for focal cartilage defects in the knee suggests that it is safe, it improves the short-term knee function and that it has the potential to recreate hyaline-like cartilage.

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

Articular cartilage injury is the most common type of damage seen in clinical orthopedic practice. The matrix-induced autologous chondrocyte implant (MACI) was developed to repair articular cartilage with an advance on the autologous chondrocyte implant procedure. This study aimed to evaluate whether MACI is a safe and efficacious cartilage repair treatment for patients with knee cartilage lesions. The primary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS) domains and magnetic resonance imaging (MRI) results, compared between baseline and postoperative months 3, 6, 12, and 24. A total of 15 patients (20 knees), with an average age of 33.9 years, had a mean defect size of 4.01 cm(2). By 6-month follow-up, KOOS results demonstrated significant improvements in symptoms and knee-related quality of life. MRI showed significant improvements in four individual graft scoring parameters at 24 months postoperatively. At 24 months, 90% of MACI grafts had filled completely and 10% had good-to-excellent filling of the chondral defect. Most (95%) of the MACI grafts were isointense and 5% were slightly hyperintense. Histologic evaluation at 15 and 24 months showed predominantly hyaline cartilage in newly generated tissue. There were no postoperative complications in any patients and no adverse events related to the MACI operation. This 2-year study has confirmed that MACI is safe and effective with the advantages of a simple technique and significant clinical improvements. Further functional and mechanistic studies with longer follow-up are needed to validate the efficacy and safety of MACI in patients with articular cartilage injuries.

Laser-structured bacterial nanocellulose hydrogels support ingrowth and differentiation of chondrocytes and show potential as cartilage implants

The small size and heterogeneity of the pores in bacterial nanocellulose (BNC) hydrogels limit the ingrowth of cells and their use as tissue-engineered implant materials. The use of placeholders during BNC biosynthesis or post-processing steps such as (touch-free) laser perforation can overcome this limitation. Since three-dimensionally arranged channels may be required for homogeneous and functional seeding, three-dimensional (3-D) laser perforation of never-dried BNC hydrogels was performed. Never-dried BNC hydrogels were produced in different shapes by: (i) the cultivation of Gluconacetobacter xylinus (DSM 14666; synonym Komagataeibacter xylinus) in nutrient medium; (ii) the removal of bacterial residues/media components (0.1M NaOH; 30 min; 100 °C) and repeated washing (deionized water; pH 5.8); (iii) the unidirectional or 3-D laser perforation and cutting (pulsed CO2 Rofin SC × 10 laser; 220 μm channel diameter); and (iv) the final autoclaving (2M NaOH; 121 °C; 20 min) and washing (pyrogen-free water). In comparison to unmodified BNC, unidirectionally perforated--and particularly 3-D-perforated - BNC allowed ingrowth into and movement of vital bovine/human chondrocytes throughout the BNC nanofiber network. Laser perforation caused limited structural modifications (i.e. fiber or globular aggregates), but no chemical modifications, as indicated by Fourier transform infrared spectroscopy, X-ray photoelectron scattering and viability tests. Pre-cultured human chondrocytes seeding the surface/channels of laser-perforated BNC expressed cartilage-specific matrix products, indicating chondrocyte differentiation. 3-D-perforated BNC showed compressive strength comparable to that of unmodified samples. Unidirectionally or 3-D-perforated BNC shows high biocompatibility and provides short diffusion distances for nutrients and extracellular matrix components. Also, the resulting channels support migration into the BNC, matrix production and phenotypic stabilization of chondrocytes. It may thus be suitable for in vivo application, e.g. as a cartilage replacement material.

Implantation of matrix-induced autologous chondrocyte (MACI ®) grafts using carbon dioxide insufflation arthroscopy

PURPOSE

The purpose of this study was to determine the safety of a new arthroscopic Matrix-induced autologous chondrocyte implant (MACI) technique with carbon dioxide insufflation utilized to improve visualization during the dry phase of the scaffold implant.

METHODS

Between 2004 and 2007, thirty patients were treated for symptomatic focal chondral lesions of the medial femoral condyle. All patients were monitored during surgery for gas embolism signs and symptoms and were evaluated preoperatively and at a median follow-up of 70.5 months (range 48-93 months) using the KOOS subjective evaluation score, the Lysholm function score, the Tegner activity scale for the knee, and the IKDC objective score.

RESULTS

No cases of intraoperative or postoperative symptoms or signs related to gas embolism or persistent subcutaneous emphysema were registered. Each subscale of the KOOS subjective score improved from preoperative to follow-up. The median Lysholm score was 50 (range 15-66) at baseline and 87.5 (range 54-100) at follow-up (p < 0.05). The median Tegner score was 2 (range 1-4) at baseline to 5 (range 2-7) at follow-up (p < 0.05).

CONCLUSIONS

No complications registered, and the satisfactory clinical results achieved in this series suggest that carbon dioxide insufflation during arthroscopic MACI is a safe and accessible option to improve visualization during the dry phase of the scaffold implant on medial femoral condyles.

Single-stage cartilage repair in the knee with microfracture covered with a resorbable polymer-based matrix and autologous bone marrow concentrate

BACKGROUND

Different single-stage surgical approaches are currently under evaluation to repair focal cartilage lesions. This study aims to analyze the clinical and histological results after treatment of focal condylar articular lesions of the knee with microfracture and subsequent covering with a resorbable polyglycolic acid/hyaluronan (PGA -HA) matrix augmented with autologous bone marrow concentrate (BMC).

METHODS

Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic PGA -HA-covered microfracture and bone marrow concentrate (PGA -HA-CMBMC). Patients were retrospectively assessed using standardized assessment tools and magnetic resonance imaging (MRI). Five patients consented to undergo second look arthroscopy and 2 consented biopsy harvest.

RESULTS

All the patients but one showed improvement in clinical scoring from the pre-operative situation to the latest follow-up (average 22±2months). The mean IKDC subjective score, Lysholm score, VAS and the median Tegner score significantly increased from baseline to the latest follow-up. Cartilage macroscopic assessment at 12months revealed that one repair appeared normal, three almost normal and one appeared abnormal. Histological analysis proofed hyaline-like cartilage repair tissue formation in one case. MRI at 8 to 12months follow-up showed complete defect filling.

CONCLUSIONS

The first clinical experience with single-stage treatment of focal cartilage defects of the knee with microfracture and covering with the PGA -HA matrix augmented with autologous BMC (PGA -HA-CMBMC) suggests that it is safe, it improves knee function and has the potential to regenerate hyaline-like cartilage.

LEVEL OF EVIDENCE

IV, case series.

Mixed Type I and Type II Collagen Scaffold for Cartilage Repair: Ultrastructural Study of Synovial Membrane Response and Healing Potential versus Microfractures (A Pilot Study)

The association between microfracture of the subchondral plate and a coverage scaffold has emerged as a promising strategy to treat cartilage lesions in a one-step procedure. Between different types of scaffolds (e.g. collagen, hyaluronic acid, polyglycolic acid) currently studied, type I collagen scaffold is the most used for this purpose, and is currently adopted for humans. The aim of this study was to test a novel scaffold made of mixed type I and II collagen (I-IICS) in order to define the immunological reaction of the synovial tissue and the repair capabilities induced by the collagen membrane when associated with microfracture. Eight New Zealand White rabbits, aged 180 days, were operated on bilaterally on the medial femoral condyle. A circular cartilage lesion was performed up to the calcified layer of the medial femoral condyle, and the centre of the lesion was microfractured. Randomly, one of the two lesions was covered with the I-IICS (treated), and the other was left uncovered (control). The synovial membrane reaction and the quality of the cartilage tissue repair were investigated at 2, 90, 180 and 270 days macroscopically, histomorphologically and ultrastructurally. Expression of tumor necrosis factor-alpha (TNF-α) in synovial tissue by immunocytochemistry analyses was also investigated. In the control group, at 2 days gold particles were localized mainly on synoviocyte type A, less on synoviocytes type B and on collagen bundles; in the treated group the reaction is more intense in cells in the matrix, but at 180 days controls and treated joints were very similar. The synovial membranes of the joints receiving the I-IICS did not reveal significant changes compared to the age-matched controls. Signs of inflammation were present at the 90-day time-point, and became less evident at afterwards. The degradation of the scaffolds was already evident at the 90-day time-point. The quality of the cartilage repair of the rabbits treated with the I-IICS was slightly better in 5 cases out of 6 in comparison to the controls. However, a statistically significant difference was not detected (p=0.06). Scaffolds made of mixed type I and II collagen exhibited good biocompatibility properties in vivo and favored cartilage restoration when associated with microfracture, as shown in this pilot study.

Matrix assisted autologous chondrocyte transplantation for cartilage treatment: A systematic review

OBJECTIVES

Matrix-assisted autologous chondrocyte transplantation (MACT) has been developed and applied in the clinical practice in the last decade to overcome most of the disadvantages of the first generation procedures. The purpose of this systematic review is to document and analyse the available literature on the results of MACT in the treatment of chondral and osteochondral lesions of the knee.

METHODS

ALL STUDIES PUBLISHED IN ENGLISH ADDRESSING MACT PROCEDURES WERE IDENTIFIED, INCLUDING THOSE THAT FULFILLED THE FOLLOWING CRITERIA: 1) level I-IV evidence, 2) measures of functional or clinical outcome, 3) outcome related to cartilage lesions of the knee cartilage.

RESULTS

The literature analysis showed a progressively increasing number of articles per year. A total of 51 articles were selected: three randomised studies, ten comparative studies, 33 case series and five case reports. Several scaffolds have been developed and studied, with good results reported at short to medium follow-up.

CONCLUSIONS

MACT procedures are a therapeutic option for the treatment of chondral lesions that can offer a positive outcome over time for specific patient categories, but high-level studies are lacking. Systematic long-term evaluation of these techniques and randomised controlled trials are necessary to confirm the potential of this treatment approach, especially when comparing against less ambitious traditional treatments.

Management of cartilage defects in the shoulder

Articular cartilage lesions of the glenohumeral joint are an especially difficult clinical problem to manage, particularly in the younger, more active patient. Left untreated, these lesions may progress in the long-term, leading to further pain and disability. While shoulder arthroplasty remains a viable option in older patients with glenohumeral arthritis, concerns over component longevity and loosening in younger patients make it less attractive in that age group. Arthroscopic joint debridement with loose body removal, often with capsular release, has been successful in select, more sedentary patients. More recent techniques, including autologous chondrocyte implantation (ACI), osteochondral grafting (allograft versus autograft), interpositional arthroplasty, and microfracture surgery, have been evaluated for use in the shoulder. These procedures have experienced success in weight bearing joints, including the knee and ankle. Despite the good clinical results in the shoulder with short-term follow-up reported in some small series, the treatment of chondral injuries in the glenohumeral joint remains a challenging problem.