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Orthopaedic Surgery Apr 2023Discoid lateral meniscus (DLM) is the most common congenital variant of the lateral meniscus, which is prone to degeneration and lesions, and often leads to knee...
Discoid lateral meniscus (DLM) is the most common congenital variant of the lateral meniscus, which is prone to degeneration and lesions, and often leads to knee osteoarthritis. At present, there is no consensus on the clinical practice of DLM, and this expert consensus and practice guidelines on DLM was developed and approved by Chinese Society of Sports Medicine according to the Delphi method. Among 32 statements drafted, 14 statements were excluded for redundant information, and 18 statements achieved consensus. This expert consensus focused on the definition, epidemiology, etiology, classification, clinical manifestations, diagnosis, treatment, prognosis, and rehabilitation of DLM. Restoring the normal shape, retaining appropriate width and thickness, and ensuring the stability of the remnant meniscus is critical to sustaining the physiological function of the meniscus and preserving the knee. The partial meniscectomy with or without repair should be the first-line treatment when possible, given that the clinical and radiological long-term outcomes of total or subtotal meniscectomy are worse.
Topics: Humans; Menisci, Tibial; Arthroscopy; Meniscectomy; Knee Joint; Meniscus
PubMed: 36878896
DOI: 10.1111/os.13687 -
Tidsskrift For Den Norske Laegeforening... Mar 2022
Topics: Humans; Meniscus; Tibial Meniscus Injuries
PubMed: 35324111
DOI: 10.4045/tidsskr.21.0540 -
International Orthopaedics Apr 2024Meniscus root tears represent significant pathology that, historically, has been underdiagnosed and undertreated. However, the recognition of their clinical and... (Review)
Review
BACKGROUND
Meniscus root tears represent significant pathology that, historically, has been underdiagnosed and undertreated. However, the recognition of their clinical and functional significance has recently surged, mainly due to their frequent association with anterior cruciate ligament injuries.
AIM
This comprehensive review discusses various aspects of meniscal root tears, including their epidemiology, biomechanics, etiology, clinical and radiological findings, classification, management and surgical techniques.
Topics: Humans; Tibial Meniscus Injuries; Arthroscopy; Anterior Cruciate Ligament Injuries; Knee Injuries; Meniscus; Menisci, Tibial
PubMed: 38261073
DOI: 10.1007/s00264-024-06092-w -
Stem Cell Research & Therapy May 2022The meniscus is a semilunar fibrocartilage between the tibia and femur that is essential for the structural and functional integrity of the keen joint. In addition to... (Review)
Review
The meniscus is a semilunar fibrocartilage between the tibia and femur that is essential for the structural and functional integrity of the keen joint. In addition to pain and knee joint dysfunction, meniscus injuries can also lead to degenerative changes of the knee joint such as osteoarthritis, which further affect patient productivity and quality of life. However, with intrinsic avascular property, the tearing meniscus tends to be nonunion and the augmentation of post-injury meniscus repair has long time been a challenge. Stem cell-based therapy with potent regenerative properties has recently attracted much attention in repairing meniscus injuries, among which mesenchymal stem cells were most explored for their easy availability, trilineage differentiation potential, and immunomodulatory properties. Here, we summarize the advances and achievements in stem cell-based therapy for meniscus repair in the last 5 years. We also highlight the obstacles before their successful clinical translation and propose some perspectives for stem cell-based therapy in meniscus repair.
Topics: Humans; Knee Injuries; Meniscus; Mesenchymal Stem Cells; Osteoarthritis, Knee; Quality of Life
PubMed: 35578310
DOI: 10.1186/s13287-022-02863-7 -
Seminars in Musculoskeletal Radiology Jun 2022Cruciate ligament reconstruction and meniscal surgery are frequently performed for restoration of knee joint stability and function after cruciate ligament and meniscus... (Review)
Review
Cruciate ligament reconstruction and meniscal surgery are frequently performed for restoration of knee joint stability and function after cruciate ligament and meniscus injuries, and they contribute to the prevention of secondary osteoarthritis. In cruciate ligaments, the most common procedure is anterior cruciate ligament (ACL) reconstruction. Meniscal surgery most frequently consists of partial meniscectomy and suture repair, rarely of a meniscus transplant. In patients with symptoms following surgery, imaging reevaluation for a suspected intra-articular source of symptoms is indicated and mainly consists of radiography and magnetic resonance imaging. For proper imaging assessment of cruciate ligament grafts and the postoperative meniscus, it is crucial to understand the surgical techniques applied, to be familiar with normal posttreatment imaging findings, and to be aware of patterns and specific findings of recurrent lesions and typical complications. This article presents an updated review of the techniques and the imaging of cruciate ligament reconstruction and meniscus surgery, recurrent lesions, treatment failure, and potential complications.
Topics: Anterior Cruciate Ligament; Anterior Cruciate Ligament Injuries; Anterior Cruciate Ligament Reconstruction; Humans; Knee Joint; Menisci, Tibial; Meniscus; Tibial Meniscus Injuries
PubMed: 35654092
DOI: 10.1055/s-0041-1741516 -
Orthopaedic Surgery Feb 2021To analyze the characteristics of menicus microstructure and to reconstruct a microstructure-mimicing 3D model of the menicus.
OBJECTIVE
To analyze the characteristics of menicus microstructure and to reconstruct a microstructure-mimicing 3D model of the menicus.
METHODS
Human and sheep meniscus were collected and prepared for this study. Hematoxylin-eosin staining (HE) and Masson staining were conducted for histological analysis of the meniscus. For submicroscopic structure analysis, the meniscus was first freeze-dried and then scanned by scanning electron microscopy (SEM). The porosity of the meniscus was determined according to SEM images. A micro-MRI was used to scan each meniscus, immersed in distilled water, and a 3D digital model was reconstructed afterwards. A three-dimensional (3D) resin model was printed out based on the digital model. Before high-resolution micro-CT scanning, each meniscus was freeze-dried. Then, micro-scale two-dimensional (2D) CT projection images were obtained. The porosity of the meniscus was calculated according to micro-CT images. With micro-CT, multiple 2D projection images were collected. A 3D digital model based on 2D CT pictures was also reconstructed. The 3D digital model was exported as STL format. A 3D resin model was printed by 3D printer based on the 3D digital model.
RESULTS
As revealed in the HE and Masson images, a meniscus is mostly composed of collagen, with a few cells disseminated between the collagen fiber bundles at the micro-scale. The SEM image clearly shows the path of highly cross-linked collagen fibers, and massive pores exist between the fibers. According to the SEM images, the porosity of the meniscus was 34.1% (34.1% ± 0.032%) and the diameters of the collagen fibers were varied. In addition, the cross-linking pattern of the fibers was irregular. The scanning accuracy of micro-MRI was 50 μm. The micro-MRI demonstrated the outline of the meniscus, but the microstructure was obscure. The micro-CT clearly displayed microfibers in the meniscus with a voxel size of 11.4 μm. The surface layer, lamellar layer, circumferential fibers, and radial fibers could be identified. The mean porosity of the meniscus according to micro-CT images was 33.92% (33.92% ± 0.03%). Moreover, a 3D model of the microstructure based on the micro-CT images was built. The microscale fibers could be displayed in the micro-CT image and the reconstructed 3D digital model. In addition, a 3D resin model was printed out based on the 3D digital model.
CONCLUSION
It is extremely difficult to artificially simulate the microstructure of the meniscus because of the irregularity of the diameter and cross-linking pattern of fibers. The micro-MRI images failed to demonstrate the meniscus microstructure. Freeze-drying and micro-CT scanning are effective methods for 3D microstructure reconstruction of the meniscus, which is an important step towards mechanically functional 3D-printed meniscus grafts.
Topics: Animals; Female; Humans; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Male; Menisci, Tibial; Microscopy, Electron, Scanning; Middle Aged; Printing, Three-Dimensional; Sheep; Tomography, X-Ray Computed
PubMed: 33403835
DOI: 10.1111/os.12899 -
Stem Cell Research & Therapy Jul 2022Tissue engineering focuses on reconstructing the damaged meniscus by mimicking the native meniscus. The application of mechanical loading on chondrocyte-laden...
BACKGROUND
Tissue engineering focuses on reconstructing the damaged meniscus by mimicking the native meniscus. The application of mechanical loading on chondrocyte-laden decellularized whole meniscus is providing the natural microenvironment. The goal of this study was to evaluate the effects of dynamic compression and shear load on chondrocyte-laden decellularized meniscus.
MATERIAL AND METHODS
The fresh samples of rabbit menisci were decellularized, and the DNA removal was confirmed by histological assessments and DNA quantification. The biocompatibility, degradation and hydration rate of decellularized menisci were evaluated. The decellularized meniscus was injected at a density of 1 × 10 chondrocyte per scaffold and was subjected to 3 cycles of dynamic compression and shear stimuli (1 h of 5% strain, ± 25°shear at 1 Hz followed by 1 h rest) every other day for 2 weeks using an ad hoc bioreactor. Cytotoxicity, GAG content, ultrastructure, gene expression and mechanical properties were examined in dynamic and static condition and compared to decellularized and intact menisci.
RESULTS
Mechanical stimulation supported cell viability and increased glycosaminoglycan (GAG) accumulation. The expression of collagen-I (COL-I, 10.7-folds), COL-II (6.4-folds), aggrecan (AGG, 3.2-folds), and matrix metalloproteinase (MMP3, 2.3-folds) was upregulated compared to the static conditions. Furthermore, more aligned fibers and enhanced tensile strength were observed in the meniscus treated in dynamic condition with no sign of mineralization.
CONCLUSION
Compress and shear stimulation mimics the loads on the joint during walking and be able to improve cell function and ultrastructure of engineered tissue to recreate a functional artificial meniscus.
Topics: Animals; Bioreactors; Chondrocytes; DNA; Glycosaminoglycans; Meniscus; Rabbits; Tissue Engineering; Tissue Scaffolds
PubMed: 35908010
DOI: 10.1186/s13287-022-03058-w -
Current Rheumatology Reports Feb 2023Meniscus injury often leads to joint degeneration and post-traumatic osteoarthritis (PTOA) development. Therefore, the purpose of this review is to outline the current... (Review)
Review
PURPOSE OF REVIEW
Meniscus injury often leads to joint degeneration and post-traumatic osteoarthritis (PTOA) development. Therefore, the purpose of this review is to outline the current understanding of biomechanical and biological repercussions following meniscus injury and how these changes impact meniscus repair and PTOA development. Moreover, we identify key gaps in knowledge that must be further investigated to improve meniscus healing and prevent PTOA.
RECENT FINDINGS
Following meniscus injury, both biomechanical and biological alterations frequently occur in multiple tissues in the joint. Biomechanically, meniscus tears compromise the ability of the meniscus to transfer load in the joint, making the cartilage more vulnerable to increased strain. Biologically, the post-injury environment is often characterized by an increase in pro-inflammatory cytokines, catabolic enzymes, and immune cells. These multi-faceted changes have a significant interplay and result in an environment that opposes tissue repair and contributes to PTOA development. Additionally, degenerative changes associated with OA may cause a feedback cycle, negatively impacting the healing capacity of the meniscus. Strides have been made towards understanding post-injury biological and biomechanical changes in the joint, their interplay, and how they affect healing and PTOA development. However, in order to improve clinical treatments to promote meniscus healing and prevent PTOA development, there is an urgent need to understand the physiologic changes in the joint following injury. In particular, work is needed on the in vivo characterization of the temporal biomechanical and biological changes that occur in patients following meniscus injury and how these changes contribute to PTOA development.
Topics: Humans; Osteoarthritis; Meniscus; Cytokines; Arthroplasty, Replacement, Knee; Cartilage, Articular
PubMed: 36479669
DOI: 10.1007/s11926-022-01093-3 -
Connective Tissue Research 2020Knee meniscus is a wedge-shaped fibrocartilaginous tissue, playing important roles in maintaining joint stability and function. Injuries to the meniscus, particularly... (Review)
Review
Knee meniscus is a wedge-shaped fibrocartilaginous tissue, playing important roles in maintaining joint stability and function. Injuries to the meniscus, particularly with the avascular inner third zone, hardly heal and frequently progress into structural breakdown, followed by the initiation of osteoarthritis. As the importance of meniscus in joint function and diseases is being recognized, the field of meniscus research is growing. Not only development, biology, and metabolism but also injury, repair, and healing of meniscus are being actively investigated. As meniscus functions as an integrated unit of a knee joint, in vivo models with various species have been the predominant method for studying meniscus pathophysiology and for testing healing/regeneration strategies. However, in vivo models for meniscus studies suffer from low reproducibility and high cost. To complement the limitations of in vivo animal models, several types of meniscus explants have been applied as highly controlled, standardized in vitro models to investigate meniscus metabolism, pathophysiology, and repair or regeneration process. This review summarizes and compares the existing meniscus explant models. We also discuss the advantages and disadvantages of each explant model. Despite few outstanding challenges, meniscus explant models have potential to serve as an effective tool for investigations of meniscus metabolism, injury, repair and healing.
Topics: Animals; Humans; Knee Injuries; Menisci, Tibial; Models, Biological; Regeneration; Tissue Culture Techniques; Tissue Engineering
PubMed: 31842590
DOI: 10.1080/03008207.2019.1702031 -
Journal of Orthopaedic Research :... Mar 2020Advanced imaging modalities, including computed tomography, magnetic resonance imaging (MRI), and dynamic fluoroscopic imaging, allow for a comprehensive evaluation of... (Review)
Review
Advanced imaging modalities, including computed tomography, magnetic resonance imaging (MRI), and dynamic fluoroscopic imaging, allow for a comprehensive evaluation of the knee joint. Compositional sequences for MRI can allow for an evaluation of the biochemical properties of cartilage, meniscus, and ligament that offer further insight into pathology that may not be apparent on conventional clinical imaging. Advances in image processing, shape modeling, and dynamic studies also offer a novel way to evaluate common conditions and to monitor patients after treatment. The purpose of this article is to review advanced imaging modalities of the knee and their current and anticipated future applications to clinical practice. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:473-482, 2020.
Topics: Biomechanical Phenomena; Body Weight; Cartilage, Articular; Computer Simulation; Femur; Fluoroscopy; Humans; Image Processing, Computer-Assisted; Knee; Knee Joint; Ligaments; Magnetic Resonance Imaging; Menisci, Tibial; Meniscus; Models, Anatomic; Tibia
PubMed: 31498473
DOI: 10.1002/jor.24462