Cartilage outgrowth in fibrin scaffolds

Minced Autologous Chondral Fragments with Fibrin Glue as a Simple Promising One-Step Cartilage Repair Procedure: A Clinical and MRI Study at 12-Month Follow-Up

OBJECTIVE

The aim of this study was to investigate early radiological and clinical outcome of autologous minced cartilage treatment as a single-step treatment option in patients with a chondral or osteochondral lesion (OCL) in the knee.

DESIGN

Eighteen patients with an OCL in the knee were included. Cartilage from healthy-appearing loose bodies and/or the periphery of the defect were minced into small chips and sealed in the defect using fibrin glue. Preoperatively, and at 3 (n = 14) and 12 (n = 18) months follow-up, magnetic resonance imaging (MRI) was performed. The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 score was used to assess the cartilage repair tissue on MRI at 12 months. The International Knee Documentation Score, Knee Injury and Osteoarthritis Outcome Score, EuroQoL-5D, and Visual Analogue Scale pain were collected preoperatively and 12 months after surgery.

RESULTS

Three months postoperative, MRI showed complete defect filling in 11 out of 14 patients. Mean MOCART 2.0 score at 12 months was 65.0 ± 18.9 with higher scores for lateral femoral chondral lesions compared to medial femoral chondral lesions (75.8 ± 14.3, 52.5 ± 15.8 respectively, P = 0.02). Clinical and statistical significant improvements were observed in the patient-reported outcome measures at 12 months postoperatively compared to preoperatively.

CONCLUSION

Treatment of OCLs using the autologous minced cartilage procedure resulted in good cartilage repair measured by MOCART 2.0. Clinically relevant improvements were observed in the clinical scores. This study suggests autologous minced cartilage as a promising, single-step treatment for OCLs.

Osteochondral Lesions of the Ankle Treated with Bone Marrow Concentrate with Hyaluronan and Fibrin: A Single-Centre Study

Osteochondral defects of the ankle (OCD) are being increasingly identified as a clinically significant consequence of injury to the ankle, with the potential to lead to osteoarthritis if left untreated. The aim of this retrospective cohort study was to evaluate a single-stage treatment of OCD, based on bone marrow aspirate (BMA) centrifuged to produce bone marrow concentrate (BMC). In a dual syringe, the concentrate was mixed with thrombin in one syringe, whereas hyaluronan and fibrinogen were mixed in a second syringe. The two mixtures were then injected and combined into the prepared defect. Clinical outcome and quality of life scores (MOXFQ and EQ-5D) were collected at baseline and yearly thereafter. Multilevel models were used to analyse the pattern of scores over time. Ninety-four patients were treated between 2015 and 2020. The means of each of the three components of the MOXFQ significantly improved between baseline and 1 year (p < 0.001 for each component), with no further change from year 1 to year 3. The EQ-5D index also improved significantly from baseline to 1 year, with no evidence for further change. Our results strongly indicate that this BMC treatment is safe for, and well tolerated by, patients with OCD of the ankle as both primary treatment and those who have failed primary treatment. This technique provides a safe, efficacious alternative to currently employed cartilage repair techniques, with favourable outcomes and a low complication rate at 36 months.

Evaluating Initial Integration of Cell-Based Chondrogenic Constructs in Human Osteochondral Explants

Integration of an implant with the surrounding tissue is a major challenge in cartilage regeneration. It is usually assessed with in vivo animal studies at the end-stage of implant development. To reduce animal experimentation and at the same time increase screening throughput and speed up implant development, this study examined whether integration of allogeneic cell-based implants with the surrounding native cartilage could be demonstrated in an ex vivo human osteochondral culture model. Chondrocytes were isolated from smooth cartilage tissue of fresh human tibial plateaus and condyles. They were expanded for 12 days either in three-dimensional spinner flask cultures to generate organoids, or in two-dimensional culture flasks for standard cell expansion. Three implant groups were created (fibrin+organoids, fibrin+cells, and fibrin only) and used to fill a Ø 6 mm full-depth chondral defect created in human osteochondral explants (Ø 10 mm, bone length cut to 4 mm) harvested from a second set of fresh human tibial plateaus. Explants were cultured for 1 or 28 days in a double-chamber culture platform. Histology showed that after 28 days the organoids on the interface of the defect remodeled and merged, and cells migrated through the fibrin glue bridging the space between the organoids and between the organoids and the native cartilage. For both conditions, newly formed tissue rich in proteoglycans and collagen type II was present mainly on the edges and in the corners of the defect. In these matrix-rich areas, cells resided in lacunae and the newly formed tissue integrated with the surrounding native cartilage. Biochemical analysis revealed a statistically significant effect of culture time on glycosaminoglycan (GAG) content, and showed a higher hydroxyproline (HYP) content for organoid-filled implants compared with cell-filled implants at both timepoints. This ex vivo human osteochondral culture system provides possibilities for exploration and identification of promising implant strategies based on evaluation of integration and matrix production under more controlled experimental conditions than possible in vivo.

Particulated Cartilage for Chondral and Osteochondral Repair: A Review

INTRODUCTION

Injuries to articular cartilage have a poor spontaneous repair potential and no gold standard treatment exist. Particulated cartilage, both auto- and allograft, is a promising new treatment method that circumvents the high cost of scaffold- and cell-based treatments.

MATERIALS AND METHODS

A comprehensive database search on particulated cartilage was performed.

RESULTS

Fourteen animal studies have found particulated cartilage to be an effective treatment for cartilage injuries. Many studies suggest that juvenile cartilage has increased regenerative potential compared to adult cartilage. Sixteen clinical studies on 4 different treatment methods have been published. (1) CAIS, particulated autologous cartilage in a scaffold, (2) Denovo NT, juvenile human allograft cartilage embedded in fibrin glue, (3) autologous cartilage chips-with and without concomitant bone grafting, and (4) augmented autologous cartilage chips.

CONCLUSION

Implantation of allogeneic and autologous particulated cartilage provides a low cost and effective treatment alternative to microfracture and autologous chondrocyte implantation. The methods are promising, but large randomized controlled studies are needed.

Diced Cartilage Techniques in Rhinoplasty

Diced cartilage has been widely applied in rhinoplasty, especially for segmental dorsal augmentation, with favorable outcomes over time. Various techniques were developed to increase both stability and viability of diced cartilage, including wrappings with non-blood material/blood products and changing the shapes of the diced cartilage, while the optimal technique is inconclusive. This article systematically reviews the current strategies of diced cartilage technique for rhinoplasty in the databases and emphasizes different wrapping materials. Free diced cartilage has a potential risk of gathering in certain regions and causing postoperative irregularities. Among non-blood wrapping materials, Surgicel is now rarely used due to severe foreign body reactions. The obvious drawbacks of fascia are donor site morbidity, inadequate quantity, and time-consuming. Although diced cartilage wrapped in tutoplast-processed fascia lata, AlloDerm, or esterified hyaluronic acid has achieved primary encouraging results, the increased inflammation raised controversies regarding their clinical use. Diced cartilage wrapped with blood products, such as platelet-rich fibrin or concentrated growth factor, achieved long-term reliable aesthetic results, and shaved cartilage and ultra-diced cartilage have recently shown satisfactory clinical outcomes, while further study is still needed. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Will Tissue-Engineering Strategies Bring New Hope for the Reconstruction of Nasal Septal Cartilage?

The nasal septal cartilage plays an important role in the growth of midface and as a vertical strut preventing the collapse of the nasal bones. The repair of nasal cartilage defects remains a major challenge in reconstructive surgery. The tissue engineering strategy in the development of tissue has opened a new perspective to generate functional tissue for transplantation. Given the poor regenerative properties of cartilage and a limited amount of autologous cartilage availability, intense interest has evoked for tissue engineering approaches for cartilage development to provide better outcomes for patients who require nasal septal reconstruction. Despite numerous attempts to substitute the shapely hyaline cartilage in the nasal cartilages, many significant challenges remained unanswered. The aim of this research was to carry out a critical review of the literature on research work carried out on the development of septal cartilage using a tissue engineering approach, concerning different cell sources, scaffolds and growth factors, as well as its clinical pathway and trials have already been carried out.

Creating Cartilage in Tissue-Engineered Chamber Using Platelet-Rich Plasma Without Cell Culture

Background: Clinically available cartilage, such as large-volume tissue-engineered cartilage, is urgently required for various clinical applications. Tissue engineering chamber (TEC) models are a promising organ-level strategy for efficient enlargement of cells or tissues within the chamber. The conventional TEC technology is not suitable for cartilage culture, because it lacks the necessary chondrogenic growth factor, which is present in platelet-rich plasma (PRP). In this study, we added autogenous auricular cartilage fragments mixed with PRP in a TEC to obtain a large amount of engineered cartilage. Experiment: To prove the efficacy of this method, 48 New Zealand white rabbits were randomly divided into 4 groups: PRP, vascularized (Ves), PRP, PRP+Ves, and control. Auricular cartilage was harvested from the rabbits, cut into fragments (2 mm), and then injected into TECs. Cartilage constructs were harvested at week 8, and construct volumes were measured. Histological morphology, immunochemical staining, and mechanical strength were evaluated. Results: At week 8, PRP+Ves constructs developed a white, cartilage-like appearance. The volume of cartilage increased by 600% the original volume from 0.30 to 1.8 ± 0.1789 mL. Histological staining showed proliferation of edge chondrocytes in the embedded cartilage in the PRP and PRP+Ves groups. Furthermore, the cartilage constructs in the PRP+Ves group show mechanical characteristics similar to those of normal cartilage. Conclusions: Auricular cartilage fragments mixed with PRP and vascularization of the TEC showed a significantly increased cartilage tissue volume after 8 weeks of incubation in rabbits. Impact Statement Repair of defects of ear cartilage tissue has always been a huge challenge to plastic surgeons. In this article, a new method is presented to produce within 8 weeks auricular cartilage in a tissue engineering chamber without cell culture. Having such a method is a valuable step toward creating a large volume of functional cartilage tissue, which may lead to successful construction of normal auricular structure with minimal donor-site morbidity.

Is There a Scientific Rationale for the Refixation of Delaminated Chondral Flaps in Femoroacetabular Impingement? A Laboratory Study

BACKGROUND

Debonding of the acetabular cartilage is a characteristic type of hip damage found in cam-type femoroacetabular impingement (FAI), which remains a treatment challenge. In addition to resection, refixation of these flaps using fibrin sealants has been recently suggested. However, there is only limited evidence available that the proposed refixation method results in sufficient viable cartilage formation to ensure long-term flap grafting and restored tissue function.

QUESTIONS/PURPOSES

To determine the flap tissue characteristics that would justify refixation of delaminated chondral flaps with a fibrin sealant, we characterized (1) the extracellular matrix (ECM) of chondral flaps in terms of chondrocyte viability and distribution of ECM components and (2) the chondrogenic potential of resident cells to migrate into fibrin and produce a cartilaginous matrix.

METHODS

Ten acetabular chondral flaps and three non-delaminated control cartilage samples were resected during surgery. Chondrocyte viability was quantified using a live-dead assay. To assess the ECM, histological staining of glycosaminoglycans, collagen II, and collagen I allowed the qualitative study of their distribution. The ability of chondrocytes to migrate out of the ECM was tested by encapsulating minced flap cartilage in fibrin gels and semi-quantitatively assessing the projected area of the gel covered with migrating cells. The potential of chondrocytes to produce a cartilaginous matrix was studied with a pellet assay, a standard three-dimensional culture system to test chondrogenesis. Positive controls were pellets of knee chondrocytes of age-matched donors, which we found in a previous study to have a good capacity to produce cartilage matrix. Statistical significance of controlled quantitative assays was determined by the Student's t-test with Welch's correction.

RESULTS

The proportion of viable chondrocytes in flaps was lower than in nondelaminated cartilage (50% ± 19% versus 76 ± 6%; p = 0.02). Histology showed a disrupted ECM in flaps compared with nondelaminated controls, with the presence of fibrillation, a loss of glycosaminoglycan at the delaminated edge, collagen II throughout the whole thickness of the flap, and some collagen I-positive area in two samples. The resident chondrocytes migrated out of this disrupted ECM in all tested samples. However in pellet culture, cells isolated from the flaps showed a qualitatively lower chondrogenic potential compared with positive controls, with a clearly inhomogeneous cell and matrix distribution and an overall smaller projected area (0.4 versus 0.7 mm; p = 0.038).

CONCLUSION

Despite the presence of viable chondrocytes with migration potential, the cells resided in a structurally altered ECM and had limited capacity to deposit ECM, leading us to question their capacity to produce sufficient ECM within the fibrin sealant for stable long-term attachment of such flaps.

CLINICAL RELEVANCE

The characterization of delaminated cartilage in cam FAI patients suggests that the refixation strategy might be adversely influenced by the low level of ECM produced by the residing cells.

Infiltration and In-Tissue Polymerization of Photocross-Linked Hydrogel for Effective Fixation of Implants into Cartilage-An In Vitro Study

Effective and biocompatible fixation of implants into cartilage defects has yet to be successfully achieved. [Poly-d,l-lactic acid/polyethyleneglycol/poly-d,l-lactic acid] (PDLLA-PEG) is a chondrosupportive scaffold that is photocross-linked using the visible-light photoinitiator lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP). Interestingly, LAP and its monomer DLLA-EG are able to infiltrate the cartilage and form hydrogels upon the detection of light. After the infiltration of LAP and DLLA-EG into the implant and host cartilage, an interconnected and continuous hydrogel structure is formed which fixes the implant within the host cartilage. A mechanical test shows that the infiltrated group displays a significantly higher push-out force than the group that has not been infiltrated (the traditional fibrin fixation group). Surprisingly, the in-cartilage hydrogel also reduces the release of sulfated glycosaminoglycan from cartilage explants. However, infiltration does not affect the cell viability or the expression of cartilage marker genes. This new strategy thus represents a biocompatible and efficient method to fix implants into host tissues.

Autologous Cartilage Chip Transplantation Improves Repair Tissue Composition Compared With Marrow Stimulation

BACKGROUND

Repair of chondral injuries by use of cartilage chips has recently demonstrated clinical feasibility.

PURPOSE

To investigate in vivo cartilage repair outcome of autologous cartilage chips compared with marrow stimulation in full-thickness cartilage defects in a minipig model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six Göttingen minipigs received two 6-mm chondral defects in the medial and lateral trochlea of each knee. The two treatment groups were (1) autologous cartilage chips embedded in fibrin glue (ACC) (n = 12) and (2) marrow stimulation (MST) (n = 12). The animals were euthanized after 6 months, and the composition of repair tissue was quantitatively determined using histomorphometry. Semiquantitative evaluation was performed by means of the International Cartilage Repair Society (ICRS) II score. Collagen type II staining was used to further evaluate the repair tissue composition.

RESULTS

Significantly more hyaline cartilage was found in the ACC (17.1%) compared with MST (2.9%) group ( P < .01). Furthermore, the ACC group had significantly less fibrous tissue (23.8%) compared with the MST group (41.1%) ( P < .01). No significant difference in fibrocartilage content was found (54.7% for ACC vs 50.8% for MST). The ACC group had significantly higher ICRS II scores for tissue morphological characteristics, matrix staining, cell morphological characteristics, surface assessment, mid/deep assessment, and overall assessment ( P < .05). The ACC-treated defects had significantly more collagen type II staining (54.5%) compared with the MST-treated defects (28.1%) ( P < .05).

CONCLUSION

ACC transplant resulted in improved quality of cartilage repair tissue compared with MST at 6 months postoperatively.

CLINICAL RELEVANCE

Further studies are needed to investigate ACC as a possible alternative first-line treatment for focal cartilage injuries in the knee.

Autologous Dual-Tissue Transplantation for Osteochondral Repair: Early Clinical and Radiological Results

BACKGROUND

Numerous treatment methods for osteochondral repair have been implemented, including auto- and allogeneic osteochondral transplantations, combined bone and chondrocyte transplantations, and synthetic implants, but no gold standard treatment has been established. We present preliminary data on a combined autologous bone and cartilage chips: autologous dual-tissue transplantation (ADTT); an easily applicable, low-cost treatment option for osteochondral repair. The aim of this study was to investigate the early biological and clinical outcome of ADTT.

MATERIALS

Eight patients (age 32 ± 7.5 years) suffering from osteochondritis dissecans (OCD) in the knee were enrolled. The OCD lesion was debrided and the osteochondral defect was filled with autologous bone, to a level at the base of the adjacent cartilage. Cartilage biopsies from the intercondylar notch were chipped and embedded within fibrin glue in the defect. Evaluation was performed using magnetic resonance imaging, computed tomography, and clinical scores, preoperative and 1 year postoperative.

RESULTS

Cartilage tissue repair evaluated using MOCART score improved from 22.5 to 52.5 (P < 0.01). Computed tomography imaging demonstrated very good subchondral bone healing with all 8 patients having a bone filling of >80%. We found improvements 1 year postoperative in the International Knee Documentation Committee score (from 35.9 to 68.1, P < 0.01), Tegner score (from 2.6 to 4.7, P < 0.05), and Knee injury and Osteoarthritis Outcome Score pain, symptoms, sport/recreation and quality of life (P < 0.05).

CONCLUSION

Treatment of OCD with ADTT resulted in very good subchondral bone restoration and good cartilage repair. Significant improvements in patient reported outcome was found at 1 year postoperative. This study suggests ADTT as a promising, low-cost, treatment option for osteochondral injuries.

Natural assembly of platelet lysate-loaded nanocarriers into enriched 3D hydrogels for cartilage regeneration

The role of Platelet Lysates (PLs) as a source of growth factors (GFs) and as main element of three-dimensional (3D) hydrogels has been previously described. However, the resulting hydrogels usually suffer from high degree of contraction, limiting their usefulness. This work describes the development of a stable biomimetic 3D hydrogel structure based on PLs, through the spontaneous assembling of a high concentration of chitosan-chondroitin sulfate nanoparticles (CH/CS NPs) with PLs loaded by adsorption. The interactions between the NPs and the lysates resemble the ones observed in the extracellular matrix (ECM) native environment between glycosaminoglycans and ECM proteins. In vitro release studies were carried out focusing on the quantification of PDGF-BB and TGF-β1 GFs. Human adipose derived stem cells (hASCs) were entrapped in these 3D hydrogels and cultured in vitro under chondrogenic stimulus, in order to assess their potential use for cartilage regeneration. Histological, immunohistological and gene expression analysis demonstrated that the PL-assembled constructs entrapping hASCs exhibited results similar to the positive control (hASCS cultured in pellets), concerning the levels of collagen II expression and immunolocalization of collagen type I and II and aggrecan. Moreover, the deposition of new cartilage ECM was detected by alcian blue and safranin-O positive stainings. This work demonstrates the potential of PLs to act simultaneously as a source/carrier of GFs and as a 3D structure of support, through the application of a "bottom-up" approach involving the assembly of NPs, resulting in an enriched construct for cartilage regeneration applications.

Limited integrative repair capacity of native cartilage autografts within cartilage defects in a sheep model

The purpose of this study was to investigate integration and cellular outgrowth of native cartilage autografts transplanted into articular cartilage defects. Native cartilage autografts were applied into chondral defects in the femoral condyle of adult sheep. Within the defects, the calcified cartilage layer was either left intact or perforated to induce bone marrow stimulation. Empty defects served as controls. The joints were analyzed after 6 and 26 weeks by macroscopic and histological analysis using the ICRS II Score and Modified O'Driscoll Scores. Non-treated defects did not show any endogenous regenerative response and bone marrow stimulation induced fibrous repair tissue. Transplanted native cartilage grafts only insufficiently integrated with the defect borders. Cell death and loss of proteoglycans were present at the margins of the grafts at 6 weeks, which was only partially restored at 26 weeks. Significant cellular outgrowth from the grafts or defect borders could not be observed. Bonding of the grafts could be improved by additional bone marrow stimulation providing ingrowing cells that formed a fibrous interface predominantly composed of type I collagen. Transplanted native cartilage grafts remain as inert structures within cartilage defects and fail to induce integrative cartilage repair which rather demands additional cells provided by additional bone marrow stimulation.

Reconstruction of focal cartilage defects in the talus with miniarthrotomy and collagen matrix

SURGICAL PRINCIPAL AND OBJECTIVE

Treatment of focal cartilage defects (traumatic or osteochondrosis dissecans) of the talus using a collagen matrix. The goal is to stabilize the superclot formed after microfracturing to accommodate cartilage repair. The procedure can be carried out via miniarthrotomy, without medial malleolus osteotomy.

INDICATIONS

International Cartilage Repair Society (ICRS) grade III and IV focal cartilage defects of the talus > 1.5 cm(2).

CONTRAINDICATIONS

Generalized osteoarthritis, inflammatory joint disease, gout, neuroarthropathy.

SURGICAL TECHNIQUE

Miniarthrotomy to open the ankle joint. Debridement of unstable cartilage and necrotic bone, curettage of cysts. Filling of the bone defects with autologous cancellous bone. Sealing of reconstructed bone with fibrin glue and attachment of a collagen matrix shaped to precisely fit the defect.

POSTOPERATIVE REGIMEN

Immobilization for 48 h. Partial weight bearing of 10 kg for 6 weeks, with continuous passive motion. Increasing weight bearing from 7 weeks onwards.

RESULTS

Follow-up of at least 30 months in 14 patients showed improvement in the Score of the American Orthopedic Foot and Ankle Society (AOFAS) from 50 to 89 points, with equal mobility on both sides of the upper ankle joint.

Physiological cartilage tissue engineering effect of oxygen and biomechanics

In vitro engineering of cartilaginous tissues has been studied for many years, and tissue-engineered constructs are sought to be used clinically for treating articular cartilage defects. Even though there is a plethora of studies and data available, no breakthroughs have been achieved yet that allow for implanting in vivo cultured articular cartilaginous tissues in patients. A review of contributions to cartilage tissue engineering over the past decades emphasizes that most of the studies were performed under environmental conditions neglecting the physiological situation. This is specifically pronounced in the use of bioreactor systems which neither allow for application of near physiomechanical stimulations nor for controlling a hypoxic environment as it is experienced in synovial joints. It is suspected that the negligence of these important parameters has slowed down progress and prevented major breakthroughs in the field. This review focuses on the main aspects of cartilage tissue engineering with emphasis on the relation and understanding of employing physiological conditions.

Advancing nasal reconstructive surgery: the application of tissue engineering technology

Cartilage tissue engineering is a rapidly progressing area of regenerative medicine with advances in cell biology and scaffold engineering constantly being investigated. Many groups are now capable of making neocartilage constructs with some level of morphological, biochemical, and histological likeness to native human cartilage tissues. The application of this useful technology in articular cartilage repair is well described in the literature; however, few studies have evaluated its application in head and neck reconstruction. Although there are many studies on auricular cartilage tissue engineering, there are few studies regarding cartilage tissue engineering for complex nasal reconstruction. This study therefore highlighted the challenges involved with nasal reconstruction, with special focus on nasal cartilage tissue, and examined how advancements made in cartilage tissue engineering research could be applied to improve the clinical outcomes of total nasal reconstructive surgery.

Key issues in nasal reconstruction

PURPOSE OF REVIEW

To review recent research and advances in nasal reconstruction over the last 12 months.

RECENT FINDINGS

Although the major principles of replacing surgically ablated tissues with like tissue and respecting the nasal aesthetic subunits have not changed, recent advances in nasal reconstruction have focused on producing superior aesthetic and functional results, while minimizing deformity and morbidity. Future directions may also include the application of allotransplantation and tissue engineering.

SUMMARY

A large variety of sophisticated techniques continue to emerge with the goal of producing increasingly natural results for patients undergoing nasal reconstruction.