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The Journal of Bone and Joint Surgery.... Nov 2012Hyaline articular cartilage has been known to be a troublesome tissue to repair once damaged. Since the introduction of autologous chondrocyte implantation (ACI) in... (Review)
Review
Hyaline articular cartilage has been known to be a troublesome tissue to repair once damaged. Since the introduction of autologous chondrocyte implantation (ACI) in 1994, a renewed interest in the field of cartilage repair with new repair techniques and the hope for products that are regenerative have blossomed. This article reviews the basic science structure and function of articular cartilage, and techniques that are presently available to effect repair and their expected outcomes.
Topics: Arthroplasty, Subchondral; Arthroscopy; Bone Transplantation; Cartilage, Articular; Chondrocytes; Humans; Hyaline Cartilage; Knee Injuries
PubMed: 23118403
DOI: 10.1302/0301-620X.94B11.30679 -
European Cells & Materials Jul 2017As a key molecule of the extracellular matrix, laminin provides a delicate microenvironment for cell functions. Recent findings suggest that laminins expressed by... (Review)
Review
As a key molecule of the extracellular matrix, laminin provides a delicate microenvironment for cell functions. Recent findings suggest that laminins expressed by cartilage-forming cells (chondrocytes, progenitor cells and stem cells) could promote chondrogenesis. However, few papers outline the effect of laminins on providing a favorable matrix microenvironment for cartilage regeneration. In this review, we delineated the expression of laminins in hyaline cartilage, fibrocartilage and cartilage-like tissue (nucleus pulposus) throughout several developmental stages. We also examined the effect of laminins on the biological activities of chondrocytes, including adhesion, migration and survival. Furthermore, we scrutinized the potential influence of various laminin isoforms on cartilage-forming cells' proliferation and chondrogenic differentiation. With this information, we hope to facilitate the understanding of the spatial and temporal interactions between cartilage-forming cells and laminin microenvironment to eventually advance cell-based cartilage engineering and regeneration.
Topics: Animals; Cartilage, Articular; Cell Proliferation; Chondrocytes; Chondrogenesis; Humans; Laminin; Regeneration
PubMed: 28731483
DOI: 10.22203/eCM.v034a03 -
American Journal of Physiology. Cell... Dec 2013To withstand physiological loading over a lifetime, human synovial joints are covered and protected by articular cartilage, a layer of low-friction, load-bearing tissue.... (Review)
Review
To withstand physiological loading over a lifetime, human synovial joints are covered and protected by articular cartilage, a layer of low-friction, load-bearing tissue. The unique mechanical function of articular cartilage largely depends on the composition and structural integrity of the cartilage matrix. The matrix is produced by highly specialized resident cells called chondrocytes. Under physiological loading, chondrocytes maintain the balance between degradation and synthesis of matrix macromolecules. Under excessive loading or injury, however, degradation exceeds synthesis, causing joint degeneration and, eventually, osteoarthritis (OA). Hence, the mechanoresponses of chondrocytes play an important role in the development of OA. Despite its clear importance, the mechanobiology of articular chondrocytes is not well understood. To summarize our current understanding, here we review studies of the effect of mechanical forces on mechanical and biological properties of articular chondrocytes. First, we present the viscoelastic properties of the cell nucleus, chondrocyte, pericellular matrix, and chondron. Then we discuss how these properties change in OA. Finally, we discuss the responses of normal and osteoarthritic chondrocytes to a variety of mechanical stimuli. Studies reviewed here may provide novel insights into the pathogenesis of OA and may help in development of effective biophysical treatment.
Topics: Biomechanical Phenomena; Cartilage, Articular; Chondrocytes; Humans; Osteoarthritis
PubMed: 24067919
DOI: 10.1152/ajpcell.00242.2013 -
Disease Models & Mechanisms Jun 2018Articular cartilage defects may initiate osteoarthritis. Subchondral drilling, a widely applied clinical technique to treat small cartilage defects, does not yield... (Meta-Analysis)
Meta-Analysis Review
Articular cartilage defects may initiate osteoarthritis. Subchondral drilling, a widely applied clinical technique to treat small cartilage defects, does not yield cartilage regeneration. Various translational studies aiming to improve the outcome of drilling have been performed; however, a robust systematic analysis of its translational evidence was still lacking. Here, we performed a systematic review of the outcome of subchondral drilling for knee cartilage repair in translational animal models. A total of 12 relevant publications studying 198 animals was identified, detailed study characteristics were extracted, and methodological quality and risk of bias were analyzed. Subchondral drilling led to improved repair outcome compared with defects that were untreated or treated with abrasion arthroplasty for cartilage repair in multiple translational models. Within the 12 studies, considerable subchondral bone changes were observed, including subchondral bone cysts and intralesional osteophytes. Furthermore, extensive alterations of the subchondral bone microarchitecture appeared in a temporal pattern in small and large animal models, together with specific topographic aspects of repair. Moreover, variable technical aspects directly affected the outcomes of osteochondral repair. The data from this systematic review indicate that subchondral drilling yields improved short-term structural articular cartilage repair compared with spontaneous repair in multiple small and large animal models. These results have important implications for future investigations aimed at an enhanced translation into clinical settings for the treatment of cartilage defects, highlighting the importance of considering specific aspects of modifiable variables such as improvements in the design and reporting of preclinical studies, together with the need to better understand the underlying mechanisms of cartilage repair following subchondral drilling.
Topics: Animals; Arthroplasty, Subchondral; Cartilage, Articular; Publication Bias; Regeneration; Research Report; Risk Factors; Translational Research, Biomedical
PubMed: 29728409
DOI: 10.1242/dmm.034280 -
Investigative Radiology Jan 2014T2* mapping is a relatively new method for the compositional assessment of the articular cartilage. Typically, a multigradient echo or an ultrashort echo time imaging... (Review)
Review
T2* mapping is a relatively new method for the compositional assessment of the articular cartilage. Typically, a multigradient echo or an ultrashort echo time imaging technique with a range of short and very short echo times is used. In most studies, imaging is performed at a high field strength, that is, 3 and 7 T. Postprocessing includes exponential fitting of relaxation decay and manual region-of-interest-based measurements of T2* times on T2* maps. Detailed analyses of T2* times of articular cartilage have shown distinct T2* components with shorter and longer T2* times. Moreover, there is a zonal distribution with a significant depthwise gradient of T2*, with relatively short times near the osteochondral junction and relatively long times at the cartilage's surface. T2* times of normal articular cartilage at the knee are, when averaged over the whole cartilage thickness and using monoexponential fitting, approximately 20 milliseconds. The results of recent studies have shown a good test-retest as well as interreader and intrareader reliabilities for T2* mapping. This article provides a descriptive review of the current literature, briefly discusses the technique itself, and provides an outlook on future research questions and possible clinical applications.
Topics: Cartilage Diseases; Cartilage, Articular; Evidence-Based Medicine; Humans; Image Enhancement; Joint Diseases; Magnetic Resonance Imaging
PubMed: 24056113
DOI: 10.1097/RLI.0b013e3182a574e1 -
Radiographics : a Review Publication of... 2022This review is intended to aid in the interpretation of damage to the articular cartilage at routine clinical MRI to improve clinical management. Relevant facets of the... (Review)
Review
This review is intended to aid in the interpretation of damage to the articular cartilage at routine clinical MRI to improve clinical management. Relevant facets of the histologic and biochemical characteristics and clinical management of cartilage are discussed, as is MRI physics. Characterization of damage to the articular cartilage with MRI demands a detailed understanding of the normal and damaged appearance of the osteochondral unit in the context of different sequence parameters. Understanding the location of the subchondral bone plate is key to determining the depth of the cartilage lesion. Defining the bone plate at MRI is challenging because of the anisotropic fibrous organization of articular cartilage, which is susceptible to the "magic angle" phenomenon and chemical shift artifacts at the interface with the fat-containing medullary cavity. These artifacts may cause overestimation of the thickness of the subchondral bone plate and, therefore, overestimation of the depth of a cartilage lesion. In areas of normal cartilage morphology, isolated hyperintense and hypointense lesions often represent degeneration of cartilage at arthroscopy. Changes in the subchondral bone marrow at MRI also increase the likelihood that cartilage damage will be visualized at arthroscopy, even when a morphologic lesion cannot be resolved, and larger subchondral lesions are associated with higher grades at arthroscopy. The clinical significance of other secondary features of cartilage damage are also reviewed, including osteophytes, intra-articular bodies, and synovitis. Work of the U.S. Government published under an exclusive license with the RSNA.
Topics: Arthroscopy; Bone Marrow; Cartilage, Articular; Humans; Magnetic Resonance Imaging
PubMed: 35984752
DOI: 10.1148/rg.220051 -
Journal of Orthopaedic Research :... Feb 2018Mature chondrocytes in adult articular cartilage vary in number, size, and shape, depending on their depth in the tissue, location in the joint, and source species.... (Review)
Review
Mature chondrocytes in adult articular cartilage vary in number, size, and shape, depending on their depth in the tissue, location in the joint, and source species. Chondrocytes are the primary structural, functional, and metabolic unit in articular cartilage, the loss of which will induce fatigue to the extracellular matrix (ECM), eventually leading to failure of the cartilage and impairment of the joint as a whole. This brief review focuses on the functional and biomechanical studies of chondrocytes and articular cartilage, using microscopic imaging from optical microscopies to scanning probe microscopy. Three topics are covered in this review, including the functional studies of chondrons by optical imaging (unpolarized and polarized light and infrared light, two-photon excitation microscopy), the probing of chondrocytes and cartilage directly using microscale measurement techniques, and different imaging approaches that can measure chondrocyte mechanics and chondrocyte biological signaling under in situ and in vivo environments. Technical advancement in chondrocyte research during recent years has enabled new ways to study the biomechanical and functional properties of these cells and cartilage. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:620-631, 2018.
Topics: Animals; Cartilage, Articular; Chondrocytes; Extracellular Matrix; Humans; Mechanotransduction, Cellular; Microscopy, Scanning Probe; Optical Imaging
PubMed: 28975657
DOI: 10.1002/jor.23757 -
Journal of Biomechanics Oct 2019Articular cartilage is an enduring tissue. For most individuals, articular cartilage facilitates a lifetime of pain-free ambulation, supporting millions of loading...
Articular cartilage is an enduring tissue. For most individuals, articular cartilage facilitates a lifetime of pain-free ambulation, supporting millions of loading cycles from activities of daily living. Although early studies into osteoarthritis focused on the role of mechanical fatigue in articular cartilage degeneration, much is still unknown regarding its strength and endurance characteristics. The compressive strength of juvenile, bovine articular cartilage explants was determined to be loading rate-dependent, reaching a maximum strength of 29.5 ± 4.8 MPa at a strain rate of 0.10 %/sec. The fatigue and endurance properties of articular cartilage were characterized utilizing a material testing system, as well as a custom, validated instrument termed the two degrees-of-freedom endurance meter (endurometer). These instruments characterized fatigue in articular cartilage explants at loading levels ranging from 10 to 80 % strength (%S), up to 100,000 cycles. Cartilage explants displayed characteristics of fatigue - fatigue life increased as the loading magnitude decreased. All explants failed within 14,000 cycles at loading levels between 50 and 80 %S. At 10 and 20 %S, all explants endured 100,000 loading cycles. There was no significant difference in equilibrium compressive modulus between run-out explants and unloaded controls, although the pooled modulus increased in response to testing. Histological staining and biochemical assays revealed no material changes in collagen, sulfated glycosaminoglycan, or hydration content between unloaded controls and explants cyclically loaded to run-out. These results suggest articular cartilage may have a putative endurance limit of 20 %S (5.86 MPa), with implications for articular cartilage biomechanics and mechanobiology.
Topics: Animals; Cartilage, Articular; Cattle; Chondrocytes; Collagen; Compressive Strength; Glycosaminoglycans; Pressure; Stress, Mechanical; Weight-Bearing
PubMed: 31447176
DOI: 10.1016/j.jbiomech.2019.07.048 -
Clinical Biomechanics (Bristol, Avon) Oct 2020Diarthrodial joints, found at the ends of long bones, function to dissipate load and allow for effortless articulation. Essential to these functions are cartilages, soft... (Review)
Review
Diarthrodial joints, found at the ends of long bones, function to dissipate load and allow for effortless articulation. Essential to these functions are cartilages, soft hydrated tissues such as hyaline articular cartilage and the knee meniscus, as well as lubricating synovial fluid. Maintaining adequate lubrication protects cartilages from wear, but a decrease in this function leads to tissue degeneration and pathologies such as osteoarthritis. To study cartilage physiology, articular cartilage researchers have employed tribology, the study of lubrication and wear between two opposing surfaces, to characterize both native and engineered tissues. The biochemical components of synovial fluid allow it to function as an effective lubricant that exhibits shear-thinning behavior. Although tribological properties are recognized to be essential to native tissue function and a critical characteristic for translational tissue engineering, tribology is vastly understudied when compared to other mechanical properties such as compressive moduli. Further, tribometer configurations and testing modalities vary greatly across laboratories. This review aims to define commonly examined tribological characteristics and discuss the structure-function relationships of biochemical constituents known to contribute to tribological properties in native tissue, address the variations in experimental set-ups by suggesting a move toward standard testing practices, and describe how tissue-engineered cartilages may be augmented to improve their tribological properties.
Topics: Animals; Biomechanical Phenomena; Cartilage, Articular; Humans; Mechanical Phenomena; Tissue Engineering
PubMed: 31676140
DOI: 10.1016/j.clinbiomech.2019.10.016 -
Osteoarthritis and Cartilage Dec 2018The objective of this study was to evaluate the effect of full-thickness chondral defects on intratissue deformation patterns and matrix constituents in an experimental...
OBJECTIVE
The objective of this study was to evaluate the effect of full-thickness chondral defects on intratissue deformation patterns and matrix constituents in an experimental model mimicking in vivo cartilage-on-cartilage contact conditions.
DESIGN
Pairs of bovine osteochondral explants, in a unique cartilage-on-cartilage model system, were compressed uniaxially by 350 N during 2 s loading and 1.4 s unloading cycles (≈1700 repetitions). Tissue deformations under quasi-steady state load deformation response were measured with displacement encoded imaging with stimulated echoes (DENSE) in a 9.4 T magnetic resonance imaging (MRI) scanner. Pre- and post-loading, T, T and T relaxation time maps were measured. We analyzed differences in strain patterns and relaxation times between intact cartilage (n = 8) and cartilage in which a full-thickness and critical sized defect was created (n = 8).
RESULTS
Under compressive loading, strain magnitudes were elevated at the defect rim, with elevated tensile and compressive principal strains (Δϵ = 4.2%, P = 0.02; Δϵ = -4.3%, P = 0.02) and maximum shear strain at the defect rim (Δγ = 4.4%, P = 0.007). The opposing cartilage showed minimal increase in strain patterns at contact with the defect rim but decreased strains opposing the defect. After defect creation, T, T and T relaxation times were elevated at the defect rim only. Following loading, the overall relaxations times of the defect tissue and especially at the rim, increased compared to intact cartilage.
CONCLUSIONS
This study demonstrates that the local biomechanical changes occurring after defect creation may induce tissue damage by increasing shear strains and depletion of cartilage constituents at the defect rim under compressive loading.
Topics: Animals; Cartilage, Articular; Cattle; Femur; Magnetic Resonance Imaging; Stress, Mechanical; Weight-Bearing
PubMed: 30195045
DOI: 10.1016/j.joca.2018.08.013