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Nims RJ, Durney KM, Cigan AD, Dusséaux A, Hung CT, Ateshian GA. Continuum theory of fibrous tissue damage mechanics using bond kinetics: application to cartilage tissue engineering. Interface Focus 2016; 6:20150063. [PMID: 26855751 DOI: 10.1098/rsfs.2015.0063] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process.
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Affiliation(s)
- Robert J Nims
- Department of Biomedical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA
| | - Krista M Durney
- Department of Biomedical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA
| | - Alexander D Cigan
- Department of Biomedical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA
| | - Antoine Dusséaux
- Department of Mechanical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA
| | - Clark T Hung
- Department of Biomedical Engineering , Columbia University , 500 West 120th Street, MC4703, New York, NY 10027 , USA
| | - Gerard A Ateshian
- Department of Biomedical Engineering, Columbia University, 500 West 120th Street, MC4703, New York, NY 10027, USA; Department of Mechanical Engineering, Columbia University, 500 West 120th Street, MC4703, New York, NY 10027, USA
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Robinson DL, Kersh ME, Walsh NC, Ackland DC, de Steiger RN, Pandy MG. Mechanical properties of normal and osteoarthritic human articular cartilage. J Mech Behav Biomed Mater 2016; 61:96-109. [PMID: 26851527 DOI: 10.1016/j.jmbbm.2016.01.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 01/09/2016] [Accepted: 01/19/2016] [Indexed: 10/22/2022]
Abstract
Isotropic hyperelastic models have been used to determine the material properties of normal human cartilage, but there remains an incomplete understanding of how these properties may be altered by osteoarthritis. The aims of this study were to (1) measure the material constants of normal and osteoarthritic human knee cartilage using isotropic hyperelastic models; (2) determine whether the material constants correlate with histological measures of structure and/or cartilage tissue damage; and (3) quantify the abilities of two common isotropic hyperelastic material models, the neo-Hookean and Yeoh models, to describe articular cartilage contact force, area, and pressure. Small osteochondral specimens of normal and osteoarthritic condition were retrieved from human cadaveric knees and from the knees of patients undergoing total knee arthroplasty and tested in unconfined compression at loading rates and large strains representative of weight-bearing activity. Articular surface contact area and lateral deformation were measured concurrently and specimen-specific finite element models then were used to determine the hyperelastic material constants. Structural parameters were measured using histological techniques while the severity of cartilage damage was quantified using the OARSI grading scale. The hyperelastic material constants correlated significantly with OARSI grade, indicating that the mechanical properties of cartilage for large strains change with tissue damage. The measurements of contact area described anisotropy of the tissue constituting the superficial zone. The Yeoh model described contact force and pressure more accurately than the neo-Hookean model, whereas both models under-predicted contact area and poorly described the anisotropy of cartilage within the superficial zone. These results identify the limits by which isotropic hyperelastic material models may be used to describe cartilage contact variables. This study provides novel data for the mechanical properties of normal and osteoarthritic human articular cartilage and enhances our ability to model this tissue using simple isotropic hyperelastic materials.
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Affiliation(s)
- Dale L Robinson
- Dept. of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Mariana E Kersh
- Dept. of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia; Dept. of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, IL 61801, USA
| | - Nicole C Walsh
- St Vincent׳s Institute of Medical Research and Department of Medicine at St Vincent׳s Hospital, University of Melbourne, Parkville, Victoria 3010, Australia
| | - David C Ackland
- Dept. of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Richard N de Steiger
- Dept. of Surgery, University of Melbourne, Parkville, Victoria 3010, Australia; Dept. of Surgery, Epworth Healthcare, Melbourne, Victoria 3010, Australia
| | - Marcus G Pandy
- Dept. of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
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Kim YS, Kang KT, Son J, Kwon OR, Choi YJ, Jo SB, Choi YW, Koh YG. Graft Extrusion Related to the Position of Allograft in Lateral Meniscal Allograft Transplantation: Biomechanical Comparison Between Parapatellar and Transpatellar Approaches Using Finite Element Analysis. Arthroscopy 2015; 31:2380-91.e2. [PMID: 26343943 DOI: 10.1016/j.arthro.2015.06.030] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 06/04/2015] [Accepted: 06/18/2015] [Indexed: 02/02/2023]
Abstract
PURPOSE To compare the relation of extrusion of the graft with the position of the allograft between the parapatellar and transpatellar approaches and to show the primary importance of an anatomically correct position by comparing the chondroprotective effects after lateral meniscal allograft transplantation (MAT) with those of normal healthy knees. METHODS Geometrical data from patients who underwent magnetic resonance imaging evaluation after lateral MAT were used as baseline input data for 3-dimensional and finite element analysis. The inclusion criteria were patients with symptomatic knees that had undergone meniscectomy who underwent lateral MAT with a minimum follow-up of 2 years. Patients with generalized arthritis, lower limb malalignment with greater than 5° valgus or varus, or uncorrected joint instability caused by ligament structure deficiency were excluded from this study. Patients were divided into the parapatellar group (25 patients) and transpatellar group (20 patients) according to surgical approach. RESULTS The mean width of the extruded meniscus was 4.32 ± 0.58 mm in the parapatellar group and 3.00 ± 0.61 mm in the transpatellar group (P < .0001). The mean relative percentage of extrusion was 42.48% ± 7.82% in the parapatellar group and 28.21% ± 4.49% in the transpatellar group (P < .0001). The mean angle between the bony bridge and the center of the tibial plateau was significantly greater in the parapatellar group (16.69° ± 2.68°) than in the transpatellar group (5.29° ± 1.55°, P < .0001). The mean distance from the entry point of the bony bridge to the center of the tibial plateau was also greater in the parapatellar group (16.68 ± 2.56 mm) than in the transpatellar group (10.81 ± 1.37 mm, P < .0001). The distance from the entry point of the bony bridge to the center of the tibial plateau significantly influenced the obliquity of the bony bridge in the parapatellar group (P = .002). On finite element analysis, the transpatellar approach was more similar to the intact knee model in terms of the contact area and stress of the lateral meniscus and medial meniscus as well as the maximum compressive and maximum shear stresses. Compared with the parapatellar approach, the transpatellar approach had lower maximum contact stress on the menisci and lower maximum compressive stress and maximum shear stress on the femoral and tibial articular surfaces. CONCLUSIONS The transpatellar approach led to a more anatomically correct positioning of the grafted meniscus with less meniscal extrusion than did the parapatellar approach in lateral MAT. Furthermore, the transpatellar model had lower maximum contact stress on the menisci than did the parapatellar model, and it also had lower maximum compressive stress and maximum shear stress on the femoral and tibial articular surfaces. CLINICAL RELEVANCE The transpatellar approach is likely to have a more anatomic placement of graft with a subsequent greater chondroprotective effect; thereby, it may reduce the overall risk of degenerative osteoarthritis after lateral MAT.
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Affiliation(s)
- Yong Sang Kim
- Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Kyoung-Tak Kang
- Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea
| | - Juhyun Son
- Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea
| | - Oh-Ryong Kwon
- Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Yun-Jin Choi
- Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Seung-Bae Jo
- Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Yoo Wang Choi
- Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea
| | - Yong-Gon Koh
- Joint Reconstruction Center, Department of Orthopaedic Surgery, Yonsei Sarang Hospital, Seoul, Republic of Korea.
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Bleuel J, Zaucke F, Brüggemann GP, Heilig J, Wolter ML, Hamann N, Firner S, Niehoff A. Moderate cyclic tensile strain alters the assembly of cartilage extracellular matrix proteins in vitro. J Biomech Eng 2015; 137:061009. [PMID: 25782164 DOI: 10.1115/1.4030053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Indexed: 12/16/2022]
Abstract
Mechanical loading influences the structural and mechanical properties of articular cartilage. The cartilage matrix protein collagen II essentially determines the tensile properties of the tissue and is adapted in response to loading. The collagen II network is stabilized by the collagen II-binding cartilage oligomeric matrix protein (COMP), collagen IX, and matrilin-3. However, the effect of mechanical loading on these extracellular matrix proteins is not yet understood. Therefore, the aim of this study was to investigate if and how chondrocytes assemble the extracellular matrix proteins collagen II, COMP, collagen IX, and matrilin-3 in response to mechanical loading. Primary murine chondrocytes were applied to cyclic tensile strain (6%, 0.5 Hz, 30 min per day at three consecutive days). The localization of collagen II, COMP, collagen IX, and matrilin-3 in loaded and unloaded cells was determined by immunofluorescence staining. The messenger ribo nucleic acid (mRNA) expression levels and synthesis of the proteins were analyzed using reverse transcription-polymerase chain reaction (RT-PCR) and western blots. Immunofluorescence staining demonstrated that the pattern of collagen II distribution was altered by loading. In loaded chondrocytes, collagen II containing fibrils appeared thicker and strongly co-stained for COMP and collagen IX, whereas the collagen network from unloaded cells was more diffuse and showed minor costaining. Further, the applied load led to a higher amount of COMP in the matrix, determined by western blot analysis. Our results show that moderate cyclic tensile strain altered the assembly of the extracellular collagen network. However, changes in protein amount were only observed for COMP, but not for collagen II, collagen IX, or matrilin-3. The data suggest that the adaptation to mechanical loading is not always the result of changes in RNA and/or protein expression but might also be the result of changes in matrix assembly and structure.
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Párraga Quiroga JM, Ito K, van Donkelaar CC. Meniscus replacement: Influence of geometrical mismatches on chondroprotective capabilities. J Biomech 2015; 48:1371-6. [PMID: 25835788 DOI: 10.1016/j.jbiomech.2015.02.063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 02/28/2015] [Indexed: 10/23/2022]
Abstract
The chondroprotective success of meniscal transplantation is variable. Poorly controlled factors such as a geometrical mismatch of the implant may be partly responsible. Clinical data, animal studies and cadaver experiments suggest that smaller transplants perform better than oversized, but clear evidence is lacking. The hypothesis of this study is that smaller menisci outperform larger ones because they distribute stresses more effectively at those particular locations that receive the highest loads. Consequently, collagen in the adjacent cartilage is protected from damage due to overstraining. Experimentally it is not possible to measure load distribution and collagen strain inside articular cartilage (AC). Therefore, a numerical model was used to determine the mechanical conditions throughout the depth of the AC. Meniscus implants with different sizes and mechanical properties were evaluated. These were compared with healthy and with meniscectomized joints. To account for the time-dependent behavior 600s of loading was simulated; results were visualized after 1s and 600s. Simulations showed that AC's strains strongly depended on implant size and loading duration. They depended less on the stiffness of the implant material. With an oversized implant, collagen strains were particularly large in the femoral AC initially and further increased upon sustained loading. The severest compressive strains occurred after sustained loading in the meniscectomized joint. Strains with an undersized meniscus were comparable to a perfectly sized implant. In conclusion, these results support the hypothesis that an undersized implant may outperform an oversized one because it distributes stresses better in the most intensely loaded joint area.
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Affiliation(s)
- J M Párraga Quiroga
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands
| | - K Ito
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands
| | - C C van Donkelaar
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands.
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Henak CR, Ateshian GA, Weiss JA. Finite element prediction of transchondral stress and strain in the human hip. J Biomech Eng 2014; 136:021021. [PMID: 24292495 DOI: 10.1115/1.4026101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 11/27/2013] [Indexed: 11/08/2022]
Abstract
Cartilage fissures, surface fibrillation, and delamination represent early signs of hip osteoarthritis (OA). This damage may be caused by elevated first principal (most tensile) strain and maximum shear stress. The objectives of this study were to use a population of validated finite element (FE) models of normal human hips to evaluate the required mesh for converged predictions of cartilage tensile strain and shear stress, to assess the sensitivity to cartilage constitutive assumptions, and to determine the patterns of transchondral stress and strain that occur during activities of daily living. Five specimen-specific FE models were evaluated using three constitutive models for articular cartilage: quasilinear neo-Hookean, nonlinear Veronda Westmann, and tension-compression nonlinear ellipsoidal fiber distribution (EFD). Transchondral predictions of maximum shear stress and first principal strain were determined. Mesh convergence analysis demonstrated that five trilinear elements were adequate through the depth of the cartilage for precise predictions. The EFD model had the stiffest response with increasing strains, predicting the largest peak stresses and smallest peak strains. Conversely, the neo-Hookean model predicted the smallest peak stresses and largest peak strains. Models with neo-Hookean cartilage predicted smaller transchondral gradients of maximum shear stress than those with Veronda Westmann and EFD models. For FE models with EFD cartilage, the anterolateral region of the acetabulum had larger peak maximum shear stress and first principal strain than all other anatomical regions, consistent with observations of cartilage damage in disease. Results demonstrate that tension-compression nonlinearity of a continuous fiber distribution exhibiting strain induced anisotropy incorporates important features that have large effects on predictions of transchondral stress and strain. This population of normal hips provides baseline data for future comparisons to pathomorphologic hips. This approach can be used to evaluate these and other mechanical variables in the human hip and their potential role in the pathogenesis of osteoarthritis (OA).
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57
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Progression of Gene Expression Changes following a Mechanical Injury to Articular Cartilage as a Model of Early Stage Osteoarthritis. ARTHRITIS 2014; 2014:371426. [PMID: 25478225 PMCID: PMC4248372 DOI: 10.1155/2014/371426] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/29/2014] [Indexed: 01/17/2023]
Abstract
An impact injury model of early stage osteoarthritis (OA) progression was developed using a mechanical insult to an articular cartilage surface to evaluate differential gene expression changes over time and treatment. Porcine patellae with intact cartilage surfaces were randomized to one of three treatments: nonimpacted control, axial impaction (2000 N), or a shear impaction (500 N axial, with tangential displacement to induce shear forces). After impact, the patellae were returned to culture for 0, 3, 7, or 14 days. At the appropriate time point, RNA was extracted from full-thickness cartilage slices at the impact site. Quantitative real-time PCR was used to evaluate differential gene expression for 18 OA related genes from four categories: cartilage matrix, degradative enzymes and inhibitors, inflammatory response and signaling, and cell apoptosis. The shear impacted specimens were compared to the axial impacted specimens and showed that shear specimens more highly expressed type I collagen (Col1a1) at the early time points. In addition, there was generally elevated expression of degradative enzymes, inflammatory response genes, and apoptosis markers at the early time points. These changes suggest that the more physiologically relevant shear loading may initially be more damaging to the cartilage and induces more repair efforts after loading.
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58
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Paschos NK, Makris EA, Hu JC, Athanasiou KA. Topographic variations in biomechanical and biochemical properties in the ankle joint: an in vitro bovine study evaluating native and engineered cartilage. Arthroscopy 2014; 30:1317-26. [PMID: 25064757 DOI: 10.1016/j.arthro.2014.05.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 04/17/2014] [Accepted: 05/19/2014] [Indexed: 02/02/2023]
Abstract
PURPOSE The purposes of this study were to identify differences in the biomechanical and biochemical properties among the articulating surfaces of the ankle joint and to evaluate the functional and biological properties of engineered neocartilage generated using chondrocytes from different locations in the ankle joint. METHODS The properties of the different topographies within the ankle joint (tibial plafond, talar dome, and distal fibula) were evaluated in 28 specimens using 7 bovine ankles; the femoral condyle was used as a control. Chondrocytes from the same locations were used to form 28 neocartilage constructs by tissue engineering using an additional 7 bovine ankles. The functional properties of neocartilage were compared with native tissue values. RESULTS Articular cartilage from the tibial plafond, distal fibula, talar dome, and femoral condyle exhibited Young modulus values of 4.8 ± 0.5 MPa, 3.9 ± 0.1 MPa, 1.7 ± 0.2 MPa, and 4.0 ± 0.5 MPa, respectively. The compressive properties of the corresponding tissues were 370 ± 22 kPa, 242 ± 18 kPa, 255 ± 26 kPa, and 274 ± 18 kPa, respectively. The tibial plafond exhibited 3-fold higher tensile properties and 2-fold higher compressive and shear moduli compared with its articulating talar dome; the same disparity was observed in neocartilage. Similar trends were detected in biochemical data for both native and engineered tissues. CONCLUSIONS The cartilage properties of the various topographic locations within the ankle are significantly different. In particular, the opposing articulating surfaces of the ankle have significantly different biomechanical and biochemical properties. The disparity between tibial plafond and talar dome cartilage and chondrocytes warrants further evaluation in clinical studies to evaluate their exact role in the pathogenesis of ankle lesions. CLINICAL RELEVANCE Therapeutic modalities for cartilage lesions need to consider the exact topographic source of the cells or cartilage grafts used. Furthermore, the capacity of generating neocartilage implants from location-specific chondrocytes of the ankle joint may be used in the future as a tool for the treatment of chondral lesions.
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Affiliation(s)
- Nikolaos K Paschos
- Department of Biomedical Engineering, University of California, Davis, California, U.S.A.; Orthopaedic Sports Medicine Center of Ioannina, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, Greece
| | - Eleftherios A Makris
- Department of Biomedical Engineering, University of California, Davis, California, U.S.A.; Department of Orthopedic Surgery and Musculoskeletal Trauma, University of Thessaly, Larisa, Greece
| | - Jerry C Hu
- Department of Biomedical Engineering, University of California, Davis, California, U.S.A
| | - Kyriacos A Athanasiou
- Department of Biomedical Engineering, University of California, Davis, California, U.S.A.; Department of Orthopaedic Surgery, Lawrence Ellison Center for Tissue Regeneration and Repair, School of Medicine, University of California, Davis, California, U.S.A..
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Neu CP. Functional imaging in OA: role of imaging in the evaluation of tissue biomechanics. Osteoarthritis Cartilage 2014; 22:1349-59. [PMID: 25278049 PMCID: PMC4185127 DOI: 10.1016/j.joca.2014.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 05/06/2014] [Accepted: 05/17/2014] [Indexed: 02/02/2023]
Abstract
Functional imaging refers broadly to the visualization of organ or tissue physiology using medical image modalities. In load-bearing tissues of the body, including articular cartilage lining the bony ends of joints, changes in strain, stress, and material properties occur in osteoarthritis (OA), providing an opportunity to probe tissue function through the progression of the disease. Here, biomechanical measures in cartilage and related joint tissues are discussed as key imaging biomarkers in the evaluation of OA. Emphasis will be placed on the (1) potential of radiography, ultrasound, and magnetic resonance imaging to assess early tissue pathomechanics in OA, (2) relative utility of kinematic, structural, morphological, and biomechanical measures as functional imaging biomarkers, and (3) improved diagnostic specificity through the combination of multiple imaging biomarkers with unique contrasts, including elastography and quantitative assessments of tissue biochemistry. In comparison to other modalities, magnetic resonance imaging provides an extensive range of functional measures at the tissue level, with conventional and emerging techniques available to potentially to assess the spectrum of preclinical to advance OA.
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Affiliation(s)
- C P Neu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
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Párraga Quiroga JM, Emans P, Wilson W, Ito K, van Donkelaar CC. Should a native depth-dependent distribution of human meniscus constitutive components be considered in FEA-models of the knee joint? J Mech Behav Biomed Mater 2014; 38:242-50. [PMID: 24747014 DOI: 10.1016/j.jmbbm.2014.03.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/09/2013] [Accepted: 03/15/2014] [Indexed: 02/04/2023]
Abstract
The depth-dependent matrix composition of articular cartilage is important for its mechanical behavior. It is unknown whether the depth-dependent matrix composition of a meniscus is similarly important for its load-bearing function. The present objective was to determine whether it is necessary to account for the native distribution of matrix components in the cross-sectional plane of the meniscus, when studying its mechanical behavior in numerical models. To address this objective, measured depth-dependent distribution of matrix contents in the human meniscus, and fitted visco-elastic mechanical properties of the collagen were used as input in FEA simulations of a knee joint. The importance of including the depth-dependent matrix component constitution in the meniscus was determined by comparing simulations with an axisymmetric representation of the knee joint, which incorporated either the depth-dependent matrix composition or homogenized matrix. Depth-dependent differences in water, collagen and proteoglycan contents were observed, but these were not significantly different. The anterior region, with significantly higher collagen content, was statistically stiffer than the posterior region. However, depth wise, stiffness did not correlate to the constitution of the tissue. GAG content was significantly higher in the posterior than in the anterior region. Visco-elastic properties of meniscus collagen were fitted against tensile test data. Simulations show that the distribution of stresses and strains in the cartilage is slightly low when the meniscus contains a depth-dependent constitution, but this difference is only modest. Therefore, this study suggests that knee joint mechanics is rather insensitive to the distribution of constitutive components in the cross section of the meniscus, and that the depth-dependent matrix distribution of the meniscus is not essential to be included in axisymmetric computational models of the knee joint.
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Affiliation(s)
- J M Párraga Quiroga
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - P Emans
- Department of Orthopaedic Surgery, University Hospital Maastricht, PO Box 7500, 6202 AZ Maastricht, The Netherlands
| | - W Wilson
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - K Ito
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - C C van Donkelaar
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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61
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Novakofski KD, Williams RM, Fortier LA, Mohammed HO, Zipfel WR, Bonassar LJ. Identification of cartilage injury using quantitative multiphoton microscopy. Osteoarthritis Cartilage 2014; 22:355-62. [PMID: 24185113 PMCID: PMC4117377 DOI: 10.1016/j.joca.2013.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/27/2013] [Accepted: 10/23/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Cartilage injury can lead to post-traumatic osteoarthritis (PTOA). Immediate post-trauma cellular and structural changes are not widely understood. Furthermore, current cellular-resolution cartilage imaging techniques require sectioning of cartilage and/or use of dyes not suitable for patient imaging. In this study, we used multiphoton microscopy (MPM) data with FDA-approved sodium fluorescein to identify and evaluate the pattern of chondrocyte death after traumatic injury. METHOD Mature equine distal metacarpal or metatarsal osteochondral blocks (OCBs) were injured by 30 MPa compressive loading delivered over 1 s. Injured and control sites were imaged unfixed and in situ 1 h post-injury with sodium fluorescein using rasterized z-scanning. MPM data was quantified in MATLAB, reconstructed in 3-D, and projected in 2-D to determine the damage pattern. RESULTS MPM images (600 per sample) were reconstructed and analyzed for cell death. The overall distribution of cell death appeared to cluster into circular (n = 7) or elliptical (n = 4) patterns (p = 0.006). Dead cells were prevalent near cracks in the matrix, with only 26.3% (SE = 5.0%, p < 0.0001) of chondrocytes near cracks being viable. CONCLUSION This study demonstrates the first application of MPM for evaluating cellular-scale cartilage injury in situ in live tissue, with clinical potential for detecting early cartilage damage. With this technique, we were able to uniquely observe two death patterns resulting from the same compressive loading, which may be related to local variability in matrix structure. These results also demonstrate proof-of-concept MPM diagnostic use in detecting subtle and early cartilage damage not detectable in any other way.
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Affiliation(s)
- K D Novakofski
- Department of Clinical Sciences, Cornell University, Ithaca, NY, USA
| | - R M Williams
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - L A Fortier
- Department of Clinical Sciences, Cornell University, Ithaca, NY, USA
| | - H O Mohammed
- Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY 14853, USA
| | - W R Zipfel
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA
| | - L J Bonassar
- Department of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA.
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Hosseini SM, Wilson W, Ito K, van Donkelaar CC. A numerical model to study mechanically induced initiation and progression of damage in articular cartilage. Osteoarthritis Cartilage 2014; 22:95-103. [PMID: 24185112 DOI: 10.1016/j.joca.2013.10.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/29/2013] [Accepted: 10/23/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Proteoglycan (PG) loss and surface roughening, early signs of osteoarthritis (OA), are likely preceded by softening of the ground substance and the collagen network. Insight in their relative importance to progression of OA may assist the development of treatment strategies for early OA. To support interpretation of experimental data, a numerical model is proposed that can predict damage progression in cartilage over time, as a consequence of excessive mechanical loading. The objective is to assess the interaction between ground substance softening and collagen fiber damage using this model. DESIGN An established cartilage mechanics model is extended with the assumption that excessive strains may damage the ground substance or the collagen network, resulting in softening of the overstrained constituent. During subsequent loading cycles the strain may or may not cross a threshold, resulting in damage to stabilize or to progress. To evaluate how softening of the ground substance and collagen may interact, damage progression is computed when either one of them, or both together are allowed to occur during stepwise increased loading. RESULTS Softening in the ground substance was predicted to localize in the superficial and transitional zone and resulted in cartilage softening. Collagen damage was most prominent in the superficial zone, with more diffuse damage penetrating deeper into the tissue, resulting in adverse strain gradients. Effects were more pronounced if both constituents developed damage in parallel. CONCLUSION Ground substance softening and collagen damage have distinct effects on cartilage mechanopathology, and damage in either one of them may promote each other.
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Affiliation(s)
- S M Hosseini
- Department of Biomedical Engineering, Gem-Z 4.101, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
| | - W Wilson
- Department of Biomedical Engineering, Gem-Z 4.101, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
| | - K Ito
- Department of Biomedical Engineering, Gem-Z 4.101, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
| | - C C van Donkelaar
- Department of Biomedical Engineering, Gem-Z 4.101, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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Hoshino Y, Fu FH, Irrgang JJ, Tashman S. Can joint contact dynamics be restored by anterior cruciate ligament reconstruction? Clin Orthop Relat Res 2013; 471:2924-31. [PMID: 23283673 PMCID: PMC3734431 DOI: 10.1007/s11999-012-2761-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Rotational kinematics has become an important consideration after ACL reconstruction because of its possible influence on knee degeneration. However, it remains unknown whether ACL reconstruction can restore both rotational kinematics and normal joint contact patterns, especially during functional activities. QUESTIONS/PURPOSES We asked whether knee kinematics (tibial anterior translation and axial rotation) and joint contact mechanics (tibiofemoral sliding distance) would be restored by double-bundle (DB) or single-bundle (SB) reconstruction. METHODS We retrospectively studied 17 patients who underwent ACL reconstruction by the SB (n = 7) or DB (n = 10) procedure. We used dynamic stereo x-ray to capture biplane radiographic images of the knee during downhill treadmill running. Tibial anterior translation, axial rotation, and joint sliding distance in the medial and lateral compartments were compared between reconstructed and contralateral knees in both SB and DB groups. RESULTS We observed reduced anterior tibial translation and increased knee rotation in the reconstructed knees compared to the contralateral knees in both SB and DB groups. The mean joint sliding distance on the medial compartment was larger in the reconstructed knees than in the contralateral knees for both the SB group (9.5 ± 3.9 mm versus 7.5 ± 4.3 mm) and the DB group (11.1 ± 1.3 mm versus 7.9 ± 3.8 mm). CONCLUSIONS Neither ACL reconstruction procedure restored normal knee kinematics or medial joint sliding. CLINICAL RELEVANCE Further study is necessary to understand the clinical significance of abnormal joint contact, identify the responsible mechanisms, and optimize reconstruction procedures for restoring normal joint mechanics after ACL injury.
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Affiliation(s)
- Yuichi Hoshino
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, Pittsburgh, PA 15213 USA ,Department of Orthopaedic Surgery, Kobe University, Kobe, Hyogo Japan
| | - Freddie H. Fu
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, Pittsburgh, PA 15213 USA
| | - James J. Irrgang
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, Pittsburgh, PA 15213 USA
| | - Scott Tashman
- Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, Pittsburgh, PA 15213 USA
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Accardi MA, McCullen SD, Callanan A, Chung S, Cann PM, Stevens MM, Dini D. Effects of fiber orientation on the frictional properties and damage of regenerative articular cartilage surfaces. Tissue Eng Part A 2013; 19:2300-10. [PMID: 23688110 DOI: 10.1089/ten.tea.2012.0580] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Articular cartilage provides a low-friction, wear-resistant surface for diarthrodial joints. Due to overloading and overuse, articular cartilage is known to undergo significant wear and degeneration potentially resulting in osteoarthritis (OA). Regenerative medicine strategies offer a promising solution for the treatment of articular cartilage defects and potentially localized early OA. Such strategies rely on the development of materials to restore some aspects of cartilage. In this study, microfibrous poly(ɛ-caprolactone) scaffolds of varying fiber orientations (random and aligned) were cultured with bovine chondrocytes for 4 weeks in vitro, and the mechanical and frictional properties were evaluated. Mechanical properties were quantified using unconfined compression and tensile testing techniques. Frictional properties were investigated at physiological compressive strains occurring in native articular cartilage. Scaffolds were sheared along the fiber direction, perpendicular to the fiber direction and in random orientation. The evolution of damage as a result of shear was evaluated via white light interferometry and scanning electron microscopy. As expected, the fiber orientation strongly affected the tensile properties as well as the compressive modulus of the scaffolds. Fiber orientation did not significantly affect the equilibrium frictional coefficient, but it was, however, a key factor in dictating the evolution of surface damage on the surface. Scaffolds shear tested perpendicular to the fiber orientation displayed the highest surface damage. Our results suggest that the fiber orientation of the scaffold implanted in the joint could strongly affect its resistance to damage due to shear. Scaffold fiber orientation should thus be carefully considered when using microfibrous scaffolds.
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Affiliation(s)
- Mario Alberto Accardi
- Tribology Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom
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65
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Influence of weak hip abductor muscles on joint contact forces during normal walking: probabilistic modeling analysis. J Biomech 2013; 46:2186-93. [PMID: 23891175 DOI: 10.1016/j.jbiomech.2013.06.030] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 06/28/2013] [Accepted: 06/30/2013] [Indexed: 11/22/2022]
Abstract
The weakness of hip abductor muscles is related to lower-limb joint osteoarthritis, and joint overloading may increase the risk for disease progression. The relationship between muscle strength, structural joint deterioration and joint loading makes the latter an important parameter in the study of onset and follow-up of the disease. Since the relationship between hip abductor weakness and joint loading still remains an open question, the purpose of this study was to adopt a probabilistic modeling approach to give insights into how the weakness of hip abductor muscles, in the extent to which normal gait could be unaltered, affects ipsilateral joint contact forces. A generic musculoskeletal model was scaled to each healthy subject included in the study, and the maximum force-generating capacity of each hip abductor muscle in the model was perturbed to evaluate how all physiologically possible configurations of hip abductor weakness affected the joint contact forces during walking. In general, the muscular system was able to compensate for abductor weakness. The reduced force-generating capacity of the abductor muscles affected joint contact forces to a mild extent, with 50th percentile mean differences up to 0.5 BW (maximum 1.7 BW). There were greater increases in the peak knee joint loads than in loads at the hip or ankle. Gluteus medius, particularly the anterior compartment, was the abductor muscle with the most influence on hip and knee loads. Further studies should assess if these increases in joint loading may affect initiation and progression of osteoarthritis.
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66
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van den Noort JC, Schaffers I, Snijders J, Harlaar J. The effectiveness of voluntary modifications of gait pattern to reduce the knee adduction moment. Hum Mov Sci 2013; 32:412-24. [DOI: 10.1016/j.humov.2012.02.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 02/13/2012] [Accepted: 02/19/2012] [Indexed: 10/26/2022]
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Poulet B, Westerhof TAT, Hamilton RW, Shefelbine SJ, Pitsillides AA. Spontaneous osteoarthritis in Str/ort mice is unlikely due to greater vulnerability to mechanical trauma. Osteoarthritis Cartilage 2013; 21:756-63. [PMID: 23467034 DOI: 10.1016/j.joca.2013.02.652] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 02/13/2013] [Accepted: 02/21/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Relative contributions of genetic and mechanical factors to osteoarthritis (OA) remain ill-defined. We have used a joint loading model found to produce focal articular cartilage (AC) lesions, to address whether genetic susceptibility to OA in Str/ort mice is related to AC vulnerability to mechanical trauma and whether joint loading influences spontaneous OA development. We also develop finite element (FE) models to examine whether AC thickness may explain any differential vulnerability to load-induced lesions. METHODS Right knees of 8-week-old Str/ort mice were loaded, AC integrity scored and thickness compared to CBA mice. Mechanical forces engendered in this model and the impact of AC thickness were simulated in C57Bl/6 mice using quasi-static FE modelling. RESULTS Unlike joints in non-OA prone CBA mice, Str/ort knees did not exhibit lateral femur (LF) lesions in response to applied loading; but exhibited thicker AC. FE modeling showed increased contact pressure and shear on the lateral femoral surface in loaded joints, and these diminished in joints containing thicker AC. Histological analysis of natural lesions in the tibia of Str/ort joints revealed that applied loading increased OA severity, proteoglycan loss and collagen type II degradation. CONCLUSION Genetic OA susceptibility in Str/ort mice is not apparently related to greater AC vulnerability to trauma, but joint loading modifies severity of natural OA lesions in the medial tibia. FE modelling suggests that thicker AC in Str/ort mice diminishes tissue stresses and protects against load-induced AC lesions in the LF but that this is unrelated to their genetic susceptibility to OA.
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Affiliation(s)
- B Poulet
- Lifestyle Research Group, The Royal Veterinary College, Royal College Street, University of London, NW1 0TU, UK.
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68
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Mononen ME, Jurvelin JS, Korhonen RK. Implementation of a gait cycle loading into healthy and meniscectomised knee joint models with fibril-reinforced articular cartilage. Comput Methods Biomech Biomed Engin 2013; 18:141-52. [PMID: 23570549 DOI: 10.1080/10255842.2013.783575] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Computational models can be used to evaluate the functional properties of knee joints and possible risk locations within joints. Current models with fibril-reinforced cartilage layers do not provide information about realistic human movement during walking. This study aimed to evaluate stresses and strains within a knee joint by implementing load data from a gait cycle in healthy and meniscectomised knee joint models with fibril-reinforced cartilages. A 3D finite element model of a knee joint with cartilages and menisci was created from magnetic resonance images. The gait cycle data from varying joint rotations, translations and axial forces were taken from experimental studies and implemented into the model. Cartilage layers were modelled as a fibril-reinforced poroviscoelastic material with the menisci considered as a transversely isotropic elastic material. In the normal knee joint model, relatively high maximum principal stresses were specifically predicted to occur in the medial condyle of the knee joint during the loading response. Bilateral meniscectomy increased stresses, strains and fluid pressures in cartilage on the lateral side, especially during the first 50% of the stance phase of the gait cycle. During the entire stance phase, the superficial collagen fibrils modulated stresses of cartilage, especially in the medial tibial cartilage. The present computational model with a gait cycle and fibril-reinforced biphasic cartilage revealed time- and location-dependent differences in stresses, strains and fluid pressures occurring in cartilage during walking. The lateral meniscus was observed to have a more significant role in distributing loads across the knee joint than the medial meniscus, suggesting that meniscectomy might initiate a post-traumatic process leading to osteoarthritis at the lateral compartment of the knee joint.
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Affiliation(s)
- Mika E Mononen
- a Department of Applied Physics , University of Eastern Finland , P.O. Box 1627, FI-70211 Kuopio , Finland
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Mattei L, Campioni E, Accardi MA, Dini D. Finite element analysis of the meniscectomised tibio-femoral joint: implementation of advanced articular cartilage models. Comput Methods Biomech Biomed Engin 2013; 17:1553-71. [DOI: 10.1080/10255842.2012.758253] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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70
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Ashwell MS, Gonda MG, Gray K, Maltecca C, O'Nan AT, Cassady JP, Mente PL. Changes in chondrocyte gene expression following in vitro impaction of porcine articular cartilage in an impact injury model. J Orthop Res 2013; 31:385-91. [PMID: 23027577 PMCID: PMC3553272 DOI: 10.1002/jor.22239] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 08/31/2012] [Indexed: 02/04/2023]
Abstract
Our objective was to monitor chondrocyte gene expression at 0, 3, 7, and 14 days following in vitro impaction to the articular surface of porcine patellae. Patellar facets were either axially impacted with a cylindrical impactor (25 mm/s loading rate) to a load level of 2,000 N or not impacted to serve as controls. After being placed in organ culture for 0, 3, 7, or 14 days, total RNA was isolated from full thickness cartilage slices and gene expression measured for 17 genes by quantitative real-time RT-PCR. Targeted genes included those encoding proteins involved with biological stress, inflammation, or anabolism and catabolism of cartilage extracellular matrix. Some gene expression changes were detected on the day of impaction, but most significant changes occurred at 14 days in culture. At 14 days in culture, 10 of the 17 genes were differentially expressed with col1a1 most significantly up-regulated in the impacted samples, suggesting impacted chondrocytes may have reverted to a fibroblast-like phenotype.
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Affiliation(s)
- Melissa S. Ashwell
- Animal Science Department, North Carolina State University, Raleigh, NC, USA
| | - Michael G. Gonda
- Animal Science Department, North Carolina State University, Raleigh, NC, USA
| | - Kent Gray
- Animal Science Department, North Carolina State University, Raleigh, NC, USA
| | - Christian Maltecca
- Animal Science Department, North Carolina State University, Raleigh, NC, USA
| | - Audrey T. O'Nan
- Animal Science Department, North Carolina State University, Raleigh, NC, USA
| | - Joseph P. Cassady
- Animal Science Department, North Carolina State University, Raleigh, NC, USA
| | - Peter L. Mente
- Joint Department of Biomedical Engineering, North Carolina State University, Raleigh, NC, USA and University of North Carolina, Chapel Hill, NC, USA
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Altered knee joint mechanics in simple compression associated with early cartilage degeneration. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2013; 2013:862903. [PMID: 23424607 PMCID: PMC3569885 DOI: 10.1155/2013/862903] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 12/13/2012] [Accepted: 01/01/2013] [Indexed: 11/18/2022]
Abstract
The progression of osteoarthritis can be accompanied by depth-dependent changes in the properties of articular cartilage. The objective of the present study was to determine the subsequent alteration in the fluid pressurization in the human knee using a three-dimensional computer model. Only a small compression in the femur-tibia direction was applied to avoid numerical difficulties. The material model for articular cartilages and menisci included fluid, fibrillar and nonfibrillar matrices as distinct constituents. The knee model consisted of distal femur, femoral cartilage, menisci, tibial cartilage, and proximal tibia. Cartilage degeneration was modeled in the high load-bearing region of the medial condyle of the femur with reduced fibrillar and nonfibrillar elastic properties and increased hydraulic permeability. Three case studies were implemented to simulate (1) the onset of cartilage degeneration from the superficial zone, (2) the progression of cartilage degeneration to the middle zone, and (3) the progression of cartilage degeneration to the deep zone. As compared with a normal knee of the same compression, reduced fluid pressurization was observed in the degenerated knee. Furthermore, faster reduction in fluid pressure was observed with the onset of cartilage degeneration in the superficial zone and progression to the middle zone, as compared to progression to the deep zone. On the other hand, cartilage degeneration in any zone would reduce the fluid pressure in all three zones. The shear strains at the cartilage-bone interface were increased when cartilage degeneration was eventually advanced to the deep zone. The present study revealed, at the joint level, altered fluid pressurization and strains with the depth-wise cartilage degeneration. The results also indicated redistribution of stresses within the tissue and relocation of the loading between the tissue matrix and fluid pressure. These results may only be qualitatively interesting due to the small compression considered.
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72
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Hosseini SM, Veldink MB, Ito K, van Donkelaar CC. Is collagen fiber damage the cause of early softening in articular cartilage? Osteoarthritis Cartilage 2013; 21:136-43. [PMID: 23010079 DOI: 10.1016/j.joca.2012.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 08/03/2012] [Accepted: 09/11/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Because collagen damage and cartilage softening have not yet been determined simultaneously in one study for the very early onset of osteoarthritis (OA), it remains questionable whether they are associated. The aim of the present study is therefore to evaluate whether indeed, initial collagen damage can be found when tissue softening occurs as a result of excessive mechanical loading. METHODS To investigate this aim, a series of specific indentation loading protocols were designed to induce and monitor cartilage softening in osteochondral explants of bovine carpometacarpal joints. The experiment contained one control group (n = 6) in which no damage was induced and four experimental groups in which samples received either a constant load of 3 (n = 5), 6 (n = 5) or 15 N (n = 6), or an increasing load (n = 7) from 2 to 13 N in 11 steps. Moreover, to determine mechanically induced collagen damage, Col2-3/4M (cumulative collagen damage) and Col2-3/4C(short) (only enzymatic damage) staining were compared. RESULTS The normalized peak and equilibrium reaction forces decreased in the groups that received increasing and 15 N peak loading. However, Col2-3/4M staining was negative in all samples, while enzymatic damage (Col2-3/4C(short)) appeared similar in experiments and in unloaded control groups. CONCLUSION It was shown that a loading magnitude threshold exists above which softening occurs in cartilage. However, in samples that did show softening, we were unable to detect collagen damage. Thus, our results demonstrate that cartilage softening most likely precedes collagen damage.
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Affiliation(s)
- S M Hosseini
- Orthopaedic Biomechanics Group, Department of Biomedical Engineering, Eindhoven University of Technology (TU/e), Eindhoven, The Netherlands.
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73
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McGann ME, Vahdati A, Wagner DR. Methods to assess in vitro wear of articular cartilage. Proc Inst Mech Eng H 2012; 226:612-22. [PMID: 23057234 DOI: 10.1177/0954411912447014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
New orthopedic implants for focal cartilage defects replace only a portion of the articulating joint and wear against the opposing cartilage surface. The objective of this study was to investigate different methodologies to quantify cartilage wear for future use in screening potential implant materials and finishes. In determining the optimal test parameters, two different cartilage surface geometries were compared: smaller specimens had a flat surface, while larger ones made contact in the center but not at the edge owing to the curvature of the articulating surface. The cartilage wear of the two geometries was compared using three different techniques: the collagen worn from the cartilage specimens was assessed with a modified wear factor, the surface damage was made visible with Indian ink and was quantified, and the change in surface roughness was measured. To interpret the experimental results, maximum shear stresses were evaluated with sliding contact finite element models. Although the modified wear factor was considered to be the most accurate assessment of cartilage wear, surface damage was an effective, inexpensive, and quick technique to evaluate potential implant materials. Flat specimens showed excessive wear at the edges owing to a non-physiologic stress concentration, while the larger specimens wore more uniformly across the surface. These results will be applied to future studies evaluating prospective implant materials.
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Affiliation(s)
- Megan E McGann
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, IN 46556, USA
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74
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The low permeability of healthy meniscus and labrum limit articular cartilage consolidation and maintain fluid load support in the knee and hip. J Biomech 2012; 45:1450-6. [DOI: 10.1016/j.jbiomech.2012.02.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 01/31/2012] [Accepted: 02/16/2012] [Indexed: 11/19/2022]
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Massey CJ, van Donkelaar CC, Vresilovic E, Zavaliangos A, Marcolongo M. Effects of aging and degeneration on the human intervertebral disc during the diurnal cycle: a finite element study. J Orthop Res 2012; 30:122-8. [PMID: 21710607 DOI: 10.1002/jor.21475] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 05/16/2011] [Indexed: 02/04/2023]
Abstract
A significant biochemical change that takes place in intervertebral disc degeneration is the loss of proteoglycans in the nucleus pulposus. Proteoglycans attract fluid, which works to reduce mechanical stresses in the solid matrix of the nucleus and provide a hydrostatic pressure to the annulus fibrosus, whose fibrous nature accommodates this stress. Our goals are to develop an osmo-poroelastic finite element model to study the relationship between proteoglycan content and the stress distribution within the disc and to analyze the effects of degeneration on the disc's diurnal mechanical response. Stress in the annulus increased with degeneration from ∼0.2 to 0.4 MPa, and an increase occurred in the center of the nucleus from 1.2 to 1.6 MPa. The osmotic pressure in the central nucleus region decreased the most with degeneration, from ∼0.42 to ∼0.1 MPa in a severely dehydrated disc. A 3% decrease in diurnal fluid lost with degeneration equated to ∼21% decrease in fluid exchange, and hence a decrease in nutrients that require convection to enter the disc. We quantified the increases in internal stresses in the nucleus and annulus throughout the various stages of degeneration, suggesting that these changes lead to further remodeling of the tissue.
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Affiliation(s)
- Christopher J Massey
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, USA
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Hannink G, van Tienen TG, Schouten AJ, Buma P. Changes in articular cartilage after meniscectomy and meniscus replacement using a biodegradable porous polymer implant. Knee Surg Sports Traumatol Arthrosc 2011; 19:441-51. [PMID: 20802995 PMCID: PMC3038217 DOI: 10.1007/s00167-010-1244-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Accepted: 08/02/2010] [Indexed: 12/01/2022]
Abstract
PURPOSE To evaluate the long-term effects of implantation of a biodegradable polymer meniscus implant on articular cartilage degeneration and compare this to articular cartilage degeneration after meniscectomy. METHODS Porous polymer polycaprolacton-based polyurethane meniscus implants were implanted for 6 or 24 months in the lateral compartment of Beagle dog knees. Contralateral knees were meniscectomized, or left intact and served as controls. Articular cartilage degeneration was evaluated in detail using India ink staining, routine histology, immunochemistry for denatured (Col2-¾M) and cleaved (Col2-¾C(short)) type II collagen, Mankin's grading system, and cartilage thickness measurements. RESULTS Histologically, fibrillation and substantial immunohistochemical staining for both denatured and cleaved type II collagen were found in all three treatment groups. The cartilage of the three groups showed identical degradation patterns. In the 24 months implant group, degradation appeared to be more severe when compared to the 6 months implant group and meniscectomy group. Significantly more cartilage damage (India ink staining, Mankin's grading system, and cartilage thickness measurements) was found in the 24 months implant group compared to the 6 months implant group and meniscectomy group. CONCLUSION Degradation of the cartilage matrix was the result of both mechanical overloading as well as localized cell-mediated degradation. The degeneration patterns were highly variable between animals. Clinical application of a porous polymer implant for total meniscus replacement is not supported by this study.
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Affiliation(s)
- Gerjon Hannink
- Orthopaedic Research Lab, Department of Orthopaedics, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | | | - Arend Jan Schouten
- Polymer Chemistry, Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Pieter Buma
- Orthopaedic Research Lab, Department of Orthopaedics, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Ding L, Heying E, Nicholson N, Stroud NJ, Homandberg GA, Guo D, Buckwalter JA, Martin JA. Mechanical impact induces cartilage degradation via mitogen activated protein kinases. Osteoarthritis Cartilage 2010; 18:1509-17. [PMID: 20813194 PMCID: PMC3013628 DOI: 10.1016/j.joca.2010.08.014] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 08/17/2010] [Accepted: 08/19/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the activation of Mitogen activated protein (MAP) kinases in and around cartilage subjected to mechanical damage and to determine the effects of their inhibitors on impaction-induced chondrocyte death and cartilage degeneration. DESIGN The phosphorylation of MAP kinases was examined with confocal microscopy and immunoblotting. The effects of MAP kinase inhibitors on impaction-induced chondrocyte death and proteoglycan (PG) loss were determined with fluorescent microscopy and 1, 9-Dimethyl-Methylene Blue (DMMB) assay. The expression of catabolic genes at mRNA levels was examined with quantitative real-time PCR. RESULTS Early p38 activation was detected at 20 min and 1h post-impaction. At 24h, enhanced phosphorylation of p38 and extracellular signal-regulated protein kinase (ERK)1/2 was visualized in chondrocytes from in and around impact sites. The phosphorylation of p38 was increased by 3.0-fold in impact sites and 3.3-fold in adjacent cartilage. The phosphorylation of ERK-1 was increased by 5.8-fold in impact zone and 5.4-fold in adjacent cartilage; the phosphorylation of ERK-2 increased by 4.0-fold in impacted zone and 3.6-fold in adjacent cartilage. Furthermore, the blocking of p38 pathway did not inhibit impaction-induced ERK activation. The inhibition of p38 or ERK pathway significantly reduced injury-related chondrocyte death and PG losses. Quantitative Real-time PCR analysis revealed that blunt impaction significantly up-regulated matrix metalloproteinase (MMP)-13, Tumor necrosis factor (TNF)-α, and ADAMTS-5 expression. CONCLUSION These findings implicate p38 and ERK mitogen activated protein kinases (MAPKs) in the post-injury spread of cartilage degeneration and suggest that the risk of post-traumatic osteoarthritis (PTOA) following joint trauma could be decreased by blocking their activities, which might be involved in up-regulating expressions of MMP-13, ADAMTS-5, and TNF-α.
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Affiliation(s)
- Lei Ding
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Emily Heying
- Department of Biology, Wartburg College, Waverly, Iowa, USA
| | - Nathan Nicholson
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Nicolas J. Stroud
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Gene A. Homandberg
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, USA
| | - Danping Guo
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, North Dakota, USA
| | - Joseph A. Buckwalter
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA, Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - James A. Martin
- Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA,Corresponding author. 500 Newton Road, 1182 Medical Laboratories, Iowa City, Iowa 52242, USA
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Plochocki JH, Ward CV, Smith DE. Evaluation of the chondral modeling theory using fe-simulation and numeric shape optimization. J Anat 2010; 214:768-77. [PMID: 19438771 DOI: 10.1111/j.1469-7580.2009.01070.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The chondral modeling theory proposes that hydrostatic pressure within articular cartilage regulates joint size, shape, and congruence through regional variations in rates of tissue proliferation. The purpose of this study is to develop a computational model using a nonlinear two-dimensional finite element analysis in conjunction with numeric shape optimization to evaluate the chondral modeling theory. The model employed in this analysis is generated from an MR image of the medial portion of the tibiofemoral joint in a subadult male. Stress-regulated morphological changes are simulated until skeletal maturity and evaluated against the chondral modeling theory. The computed results are found to support the chondral modeling theory. The shape-optimized model exhibits increased joint congruence, broader stress distributions in articular cartilage, and a relative decrease in joint diameter. The results for the computational model correspond well with experimental data and provide valuable insights into the mechanical determinants of joint growth. The model also provides a crucial first step toward developing a comprehensive model that can be employed to test the influence of mechanical variables on joint conformation.
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79
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Fick JM, Thambyah A, Broom ND. Articular cartilage compression: how microstructural response influences pore pressure in relation to matrix health. Connect Tissue Res 2010; 51:132-49. [PMID: 20001847 DOI: 10.3109/03008200903125229] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Our research investigated the influence of degeneration on both the pore-pressure development and microstructural response of cartilage during indentation with a flat-porous-indenter. Experiments were conducted to link the mechanical and structural responses of normal and degenerate articular cartilage. We found that from the instant of loading the degenerate matrix generated a higher peak hydrostatic excess pore pressure in a shorter period of time than the normal matrix. Following the attainment of this peak value the pore pressure in both tissue groups then gradually decayed toward zero over time, thus demonstrating a classical consolidation response. The microstructural analysis provided a unique insight into the influence of degeneration on the mechanisms of internal stress-sharing within the loaded matrix. Both disruption of the articular surface and general matrix destructuring results in an altered deformation field in both the directly loaded and nondirectly loaded regions. It is argued that the higher levels of matrix shear combined with less of the applied load being redirected into the wider cartilage continuum accounts for the elevated levels of peak hydrostatic pore pressure generated in the degenerate matrix.
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Affiliation(s)
- James M Fick
- Biomaterials Laboratory, Department of Chemical and Materials Engineering, University of Auckland, Auckland, New Zealand
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80
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BÖTTCHER PETER, ZEISSLER MARKUS, MAIERL JOHANN, GREVEL VERA, OECHTERING GERHARD. Mapping of Split-Line Pattern and Cartilage Thickness of Selected Donor and Recipient Sites for Autologous Osteochondral Transplantation in the Canine Stifle Joint. Vet Surg 2009; 38:696-704. [DOI: 10.1111/j.1532-950x.2009.00527.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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81
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Gratz KR, Wong BL, Bae WC, Sah RL. The effects of focal articular defects on cartilage contact mechanics. J Orthop Res 2009; 27:584-92. [PMID: 18979528 PMCID: PMC2862585 DOI: 10.1002/jor.20762] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 08/01/2008] [Indexed: 02/04/2023]
Abstract
Focal damage to articular cartilage is common in arthroscopy patients, and may contribute to progressive tissue degeneration by altering the local mechanical environment. The effects of a focal defect, which may be oriented at various orientations relative to the subchondral bone, on the dynamics of cartilage contact and deformation are unclear. The objective of this study was to elucidate the effect of experimental full thickness focal defects, oriented at 80 degrees or 100 degrees relative to the subchondral bone, on intratissue strain and surface sliding of opposing cartilage surfaces during compression and stress relaxation. Pairs of intact bovine osteochondral blocks were compressed uniaxially by 20%, and allowed to stress relax. Tissue deformation was recorded by video microscopy. A full-thickness defect (with either 80 degrees or 100 degrees edges) was created in one block from each pair. Blocks were allowed to reswell and retested. Defect edges were then recut with the opposite orientation, allowed to reswell, and retested again. Stained nuclei were tracked by digital image correlation and used to quantify cartilage strains and surface sliding. The results indicated that loading of intact samples caused axial strain magnitudes that decreased with depth and relatively little sliding. With loading of samples containing defects, strain magnitudes were elevated in cartilage adjacent to, and opposing, defects. For samples with edge orientations of 100 degrees, sliding magnitudes were increased over surfaces adjacent to defects. These local mechanical changes due to full-thickness articular cartilage defects may contribute to altered chondrocyte metabolism, tissue damage, or accelerated wear.
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Affiliation(s)
- Kenneth R. Gratz
- Department of Bioengineering, University of California-San Diego, La Jolla, CA
| | - Benjamin L. Wong
- Department of Bioengineering, University of California-San Diego, La Jolla, CA
| | - Won C. Bae
- Department of Radiology, University of California-San Diego, La Jolla, CA
| | - Robert L. Sah
- Department of Bioengineering, University of California-San Diego, La Jolla, CA
- Stein Institute for Research on Aging, University of California-San Diego, La Jolla, CA
- Whitaker Institute of Biomedical Engineering, University of California-San Diego, La Jolla, CA
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82
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Cancel M, Grimard G, Thuillard-Crisinel D, Moldovan F, Villemure I. Effects of in vivo static compressive loading on aggrecan and type II and X collagens in the rat growth plate extracellular matrix. Bone 2009; 44:306-15. [PMID: 18849019 DOI: 10.1016/j.bone.2008.09.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 09/04/2008] [Accepted: 09/08/2008] [Indexed: 11/23/2022]
Abstract
Mechanical loads are essential to normal bone growth, but excessive loads can lead to progressive deformities. In addition, growth plate extracellular matrix remodelling is essential to regulate the normal longitudinal bone growth process and to ensure physiological bone mineralization. In order to investigate the effects of static compression on growth plate extracellular matrix using an in vivo animal model, a loading device was used to precisely apply a compressive stress of 0.2 MPa for two weeks on the seventh caudal vertebra (Cd7) of rats during the pubertal growth spurt. Control, sham and loaded groups were studied. Growth modulation was quantified based on calcein labelling, and three matrix components (type II and X collagens, and aggrecan) were assessed using immunohistochemistry/safranin-O staining. As well, extracellular matrix components and enzymes (MMP-3 and -13, ADAMTS-4 and -5) were studied by qRT-PCR. Loading reduced Cd7 growth by 29% (p<0.05) and 15% (p=0.07) when compared to controls and shams respectively. No significant change could be observed in the mRNA expression of collagens and the proteolytic enzyme MMP-13. However, MMP-3 was significantly increased in the loaded group as compared to the control group (p<0.05). No change was observed in aggrecan and ADAMTS-4 and -5 expression. Low immunostaining for type II and X collagens was observed in 83% of the loaded rats as compared to the control rats. This in vivo study shows that, during pubertal growth spurt, two-week static compression reduced caudal vertebrae growth rates; this mechanical growth modulation occurred with decreased type II and X collagen proteins in the growth plate.
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Affiliation(s)
- Mathilde Cancel
- Department of Mechanical Engineering, Ecole Polytechnique de Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, Québec, Canada H3C 3A7.
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83
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84
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Athanasiou KA, Almarza AJ, Detamore MS, Kalpakci KN. Tissue Engineering of Temporomandibular Joint Cartilage. ACTA ACUST UNITED AC 2009. [DOI: 10.2200/s00198ed1v01y200906tis002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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85
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Anderst WJ, Tashman S. The association between velocity of the center of closest proximity on subchondral bones and osteoarthritis progression. J Orthop Res 2009; 27:71-7. [PMID: 18634007 PMCID: PMC2605192 DOI: 10.1002/jor.20702] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Altered surface interactions following joint instability may apply novel, damaging loads to articular cartilage. This study measured the velocity of the centers of closest proximity on subchondral bone surfaces on the femur and tibia during running in normal and unstable canine stifle (knee) joints. The purpose was to explore the relationship between the velocity of the centers of closest proximity on subchondral bones and the severity of cartilage damage. Dynamic biplane radiography was used to acquire serial knee kinematics [5 control, 18 cranial cruciate ligament (CCL) deficient] during treadmill running over 2 years. Custom software calculated the difference between the rate at which the center of closest proximity on the femur translated relative to the femur bone surface and the rate at which the center of closest proximity on the tibia translated relative to the tibia bone surface. Comparisons were made between dogs that developed minor versus major medial compartment cartilage damage over 2 years. Major damage dogs showed a significantly greater increase in the difference between femur and tibia medial compartment closest proximity point velocity from the instant of paw strike to peak velocity difference at 2, 4, and 6 months after CCL transaction. This implies increased tangential forces associated with the velocity of the compressed cartilage region during joint movement (plowing) may be a mechanism that initiates osteoarthritis (OA) development and drives OA progression. In the future, articulating surface velocity measurements may be useful to identify patients at risk for long-term OA due to joint instability.
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Affiliation(s)
- William J Anderst
- Department of Orthopedics, Biodynamics Lab, University of Pittsburgh, Pittsburgh, Pennsylvania 15203, USA.
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86
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McKinley TO, Tochigi Y, Rudert MJ, Brown TD. The effect of incongruity and instability on contact stress directional gradients in human cadaveric ankles. Osteoarthritis Cartilage 2008; 16:1363-9. [PMID: 18511308 PMCID: PMC2592197 DOI: 10.1016/j.joca.2008.04.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 04/04/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Measure incongruity and instability-associated changes in transient contact stress directional gradients in a human cadaveric ankle model. METHODS Seven cadaveric ankles were subjected to quasi-physiologic forces and motion under intact conditions and with a stepoff incongruity of the anterior one-third of the distal tibia. Anterior/posterior forces were modulated to create incongruous specimens that either maintained a stable articulation between the talus and distal tibia or developed gross instability during motion. Real-time contact stresses were measured using a custom-designed ankle stress transducer at 132 Hz. Contact stress data were differentiated using a central-differencing formula to calculate transient contact stress directional gradients over the entire ankle articulation. RESULTS Transient 95th percentile contact stress directional gradient values increased by 30 and 100%, respectively, in stable-incongruous and unstable-incongruous conditions compared to intact conditions. Compared to stable-incongruous conditions, transient contact stress directional gradients increased by 60% in unstable-incongruous conditions. CONCLUSIONS Instability resulted in greater percentage increases in transient contact stress directional gradients compared to incongruity. Pathologic increases in contact stress directional gradients potentially play an important role in the etiology of post-traumatic arthritis.
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Affiliation(s)
- T O McKinley
- Orthopaedics Biomechanics Laboratory, Department of Orthopaedic Surgery, University of Iowa, Iowa City, IA 52242, USA.
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87
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Verhulp E, Van Rietbergen B, Muller R, Huiskes R. Micro-finite element simulation of trabecular-bone post-yield behaviour--effects of material model, element size and type. Comput Methods Biomech Biomed Engin 2008; 11:389-95. [PMID: 18568833 DOI: 10.1080/10255840701848756] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Micro-finite element (micro-FE) analysis became a standard tool for the evaluation of trabecular bone mechanical properties. The accuracy of micro-FE models for linear analyses is well established. However, the accuracy of recently developed nonlinear micro-FE models for simulations of trabecular bone failure is not known. In this study, a trabecular bone specimen was compressed beyond the apparent yield point. The experiment was simulated using different micro-FE meshes with different element sizes and types, and material models based on cortical bone. The results from the simulations were compared with experimental results to study the effects of the different element and material models. It was found that a decrease in element size from 80 to 40 mum had little effect on predicted post-yield behaviour. Element type and material model had significant effects. Nevertheless, none of the established material models for cortical bone were able to predict the typical descent in the load-displacement curve seen during compression of trabecular bone.
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Affiliation(s)
- E Verhulp
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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88
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Ashwell MS, O'Nan AT, Gonda MG, Mente PL. Gene expression profiling of chondrocytes from a porcine impact injury model. Osteoarthritis Cartilage 2008; 16:936-46. [PMID: 18276170 DOI: 10.1016/j.joca.2007.12.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 12/22/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To identify differentially expressed genes between axially impacted and control articular cartilage taken from porcine patellae maintained in organ culture for 14 days. METHODS Porcine patellae were impacted perpendicular to the articular surface to create an impact injury. Intact patellae (control and impacted) were maintained in culture for 14 days. Total RNA was then extracted from the articular cartilage beneath the impaction and used to prepare two Serial Analysis of Gene Expression (SAGE) libraries. Approximately 42,500 SAGE long tags were sequenced from the libraries. The expression of select genes was confirmed by quantitative real-time PCR analysis. RESULTS Thirty-nine SAGE tags were significantly differentially expressed in the impacted and control libraries, representing 30 different annotated pig genes. These genes represented gene products associated with matrix molecules, iron and phosphate transport, protein biosynthesis, skeletal development, cell proliferation, lipid metabolism and the inflammatory response. Twenty-three of the 30 genes were down-regulated in the impacted library and five were up-regulated in the impacted library. Quantitative real-time PCR follow-up of four genes supported the results found with SAGE. CONCLUSION We have identified 30 putative genes differentially expressed in a porcine impact injury model and validated these findings for four of these genes using real-time PCR. Results using this impact injury model have contributed further evidence that damaged chondrocytes may de-differentiate into fibroblast-like cells and proliferate in an attempt to repair themselves. Additional work is underway to study these genes in further detail at earlier time points to provide a more complete story about the fate of chondrocytes in articular cartilage following an injury.
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Affiliation(s)
- M S Ashwell
- Department of Animal Science, North Carolina State University, Raleigh, NC 27695, United States.
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89
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Vaziri A, Nayeb-Hashemi H, Singh A, Tafti BA. Influence of meniscectomy and meniscus replacement on the stress distribution in human knee joint. Ann Biomed Eng 2008; 36:1335-44. [PMID: 18496753 DOI: 10.1007/s10439-008-9515-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Accepted: 05/05/2008] [Indexed: 01/10/2023]
Abstract
Studying the mechanics of the knee joint has direct implications in understanding the state of human health and disease and can aid in treatment of injuries. In this work, we developed an axisymmetric model of the human knee joint using finite element method, which consisted of separate parts representing tibia, meniscus and femoral, and tibial articular cartilages. The articular cartilages were modeled as three separate layers with different material characteristics: top superficial layer, middle layer, and calcified layer. The biphasic characteristic of both meniscus and cartilage layers were included in the computational model. The developed model was employed to investigate several aspects of mechanical response of the knee joint under external loading associated with the standing posture. Specifically, we studied the role of the material characteristic of the articular cartilage and meniscus on the distribution of the shear stresses in the healthy knee joint and the knee joint after meniscectomy. We further employed the proposed computational model to study the mechanics of the knee joint with an artificial meniscus. Our calculations suggested an optimal elastic modulus of about 110 MPa for the artificial meniscus which was modeled as a linear isotropic material. The suggested optimum stiffness of the artificial meniscus corresponds to the stiffness of the physiological meniscus in the circumferential direction.
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Affiliation(s)
- Ashkan Vaziri
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
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90
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Shirazi R, Shirazi-Adl A. Deep vertical collagen fibrils play a significant role in mechanics of articular cartilage. J Orthop Res 2008; 26:608-15. [PMID: 18050338 DOI: 10.1002/jor.20537] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The primary orientation of collagen fibrils alters along the cartilage depth; being horizontal in the superficial zone, random in the transitional zone, and vertical in the deep zone. Commonly used confined and unconfined (when with no underlying bone) testing configurations cannot capture the mechanical role of deep vertical fibril network. To determine this role in cartilage mechanics, an axisymmetric nonlinear fibril-reinforced poroelastic model of tibial cartilage plateaus was developed accounting for depth-dependent properties and distinct fibril networks with physical material properties. Both creep and relaxation indentation models were analyzed which results were found equivalent in the transient period but diverged in post-transient periods. Vertical fibrils played a significant role at the transient period in dramatically increasing the stiffness of the tissue and in protecting the solid matrix against large distortions and strains at the subchondral junction. This role, however, disappeared both with time and at loading rates slower than those expected in physiological activities such as walking. The vertical fibrils demonstrated a chevron-type deformation pattern that was further accentuated with time in creep loading. Damages to deep vertical collagen fibril network or their firm anchorage to the bone, associated with bone bruises, for example, would weaken the transient stiffness and place the tissue at higher risk of failure particularly at the deep zone.
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Affiliation(s)
- R Shirazi
- Division of Applied Mechanics, Department of Mechanical Engineering, Ecole Polytechnique, P.O. Box 6079, Station centre-ville, Montréal, Québec, Canada
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91
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Chaudhari AMW, Briant PL, Bevill SL, Koo S, Andriacchi TP. Knee kinematics, cartilage morphology, and osteoarthritis after ACL injury. Med Sci Sports Exerc 2008; 40:215-22. [PMID: 18202582 DOI: 10.1249/mss.0b013e31815cbb0e] [Citation(s) in RCA: 269] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review examines a mechanism for the initiation of osteoarthritis after anterior cruciate ligament (ACL) injury by considering the relationship between reported ambulatory changes after ACL injury, cartilage adaptation to load, and the association between cartilage loads during walking and regional variations in cartilage structure and biology. Taken together, these observations suggest that cartilage degeneration after ACL injury could be caused by a kinematic gait change that shifts ambulatory loading applied to cartilage. Such a shift may cause regions of cartilage to become newly loaded, be subjected to altered levels of compression and tension, or become unloaded. The metabolic sensitivity of chondrocytes to such changes in their mechanical environment, combined with the low adaptation potential of mature cartilage, could lead to cartilage degeneration and premature osteoarthritis after ACL injury. This proposed mechanism demonstrates the value of using the ACL injury model to understand the relationship between mechanics and biology, as well as helping to explain the importance of restoring normal ambulatory kinematics after ACL injury to avoid premature osteoarthritis.
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Affiliation(s)
- Ajit M W Chaudhari
- Department of Orthopaedics, OSU Sports Medicine Center, Ohio State University, 2050 Kenny Road, Columbus, OH 43221, USA.
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92
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Tanaka E, Iwabuchi Y, Rego EB, Koolstra JH, Yamano E, Hasegawa T, Kawazoe A, Kawai N, Tanne K. Dynamic shear behavior of mandibular condylar cartilage is dependent on testing direction. J Biomech 2008; 41:1119-23. [DOI: 10.1016/j.jbiomech.2007.12.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 12/13/2007] [Accepted: 12/20/2007] [Indexed: 11/13/2022]
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93
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Peña E, Calvo B, Martínez MA, Doblaré M. Computer simulation of damage on distal femoral articular cartilage after meniscectomies. Comput Biol Med 2008; 38:69-81. [PMID: 17868667 DOI: 10.1016/j.compbiomed.2007.07.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 05/24/2007] [Accepted: 07/04/2007] [Indexed: 11/16/2022]
Abstract
It is commonly accepted that total or partial meniscectomies cause wear of articular cartilages that leads to severe damage in a period of few years. This also produces alteration of the biomechanical environment and increases articular instability, with a progressive and degenerative arthrosic pathology. Due to these negative consequences, total meniscectomy technique has been avoided, with a clear preference for partial meniscectomies. Despite the better results obtained with this latter technique, it has been demonstrated that the knee still suffers progressive long-term wear, which alters the properties of the surface of articular cartilage. In this paper, a phenomenological isotropic damage model of articular cartilage is presented and implemented in a finite element code. We hypothesized that there is a relation between the increase of shear stress and cartilage degeneration. To confirm the hypothesis, the obtained results were compared to experimental ones. It is used to investigate the effect of meniscectomies on articular damage in the human knee joint. Two different situations were compared for the tibio-femoral joint: healthy and after meniscectomy. The distribution of damaged regions and the damage level distribution resulted qualitatively similar to experimental results, showing, for instance that, after meniscectomy, significant degeneration occurs in the lateral compartment. A noteworthy result was that patterns of damage in a total meniscectomy model give better agreement to clinical results when using relative increases in shear stress, rather than an absolute shear stress criterion. The predictions for partial meniscectomies indicated the relative severity of the procedures.
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Affiliation(s)
- E Peña
- Department of Mechanical Engineering, University of Zaragoza, María de Luna, 3, E-50018 Zaragoza, Spain.
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94
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Tanaka E, Rego EB, Iwabuchi Y, Inubushi T, Koolstra JH, van Eijden TMGJ, Kawai N, Kudo Y, Takata T, Tanne K. Biomechanical response of condylar cartilage-on-bone to dynamic shear. J Biomed Mater Res A 2008; 85:127-32. [PMID: 17688244 DOI: 10.1002/jbm.a.31500] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Shear stress can result in fatigue, damage, and irreversible deformation of the mandibular condylar cartilage. However, little information is available on its dynamic properties in shear. We tested the hypothesis that the dynamic shear properties of the condylar cartilage depend on the frequency and amplitude of shear strain. Ten porcine mandibular condyles were used for dynamic shear tests. Two cartilage-bone plugs were dissected from each condyle and tested in a simple shear sandwich configuration under a compressive strain of 10%. Sinusoidal shear strain was applied with an amplitude of 1.0, 2.0, and 3.0% and a frequency range between 0.01 and 10 Hz. The magnitudes of the shear dynamic moduli were found to be dependent on the frequency and the shear strain amplitude. They increased with shear strain. tan delta ranged from 0.2 to 0.4, which means that the cartilage is primarily elastic in nature and has a small but not negligible viscosity. In conclusion, the present results show that the shear behavior of the mandibular condylar cartilage is dependent on the frequency and amplitude of the applied shear strain. The observed shear characteristics suggest a significant role of shear strain on the interstitial fluid flow within the cartilage.
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Affiliation(s)
- Eiji Tanaka
- Department of Orthodontics and Craniofacial Developmental Biology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
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95
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Moroni L, Lambers FM, Wilson W, van Donkelaar CC, de Wijn JR, Huiskesb R, van Blitterswijk CA. Finite Element Analysis of Meniscal Anatomical 3D Scaffolds: Implications for Tissue Engineering. Open Biomed Eng J 2007; 1:23-34. [PMID: 19662124 PMCID: PMC2701084 DOI: 10.2174/1874120700701010023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/11/2007] [Accepted: 07/12/2007] [Indexed: 11/22/2022] Open
Abstract
Solid Free-Form Fabrication (SFF) technologies allow the fabrication of anatomical 3D scaffolds from computer tomography (CT) or magnetic resonance imaging (MRI) patients’ dataset. These structures can be designed and fabricated with a variable, interconnected and accessible porous network, resulting in modulable mechanical properties, permeability, and architecture that can be tailored to mimic a specific tissue to replace or regenerate. In this study, we evaluated whether anatomical meniscal 3D scaffolds with matching mechanical properties and architecture are beneficial for meniscus replacement as compared to meniscectomy. After acquiring CT and MRI of porcine menisci, 3D fiber-deposited (3DF) scaffolds were fabricated with different architectures by varying the deposition pattern of the fibers comprising the final structure. The mechanical behaviour of 3DF scaffolds with different architectures and of porcine menisci was measured by static and dynamic mechanical analysis and the effect of these tissue engineering templates on articular cartilage was assessed by finite element analysis (FEA) and compared to healthy conditions or to meniscectomy. Results show that 3DF anatomical menisci scaffolds can be fabricated with pore different architectures and with mechanical properties matching those of natural menisci. FEA predicted a beneficial effect of meniscus replacement with 3D scaffolds in different mechanical loading conditions as compared to meniscectomy. No influence of the internal scaffold architecture was found on articular cartilage damage. Although FEA predictions should be further confirmed by in vitro and in vivo experiments, this study highlights meniscus replacement by SFF anatomical scaffolds as a potential alternative to meniscectomy.
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Affiliation(s)
- L Moroni
- Institute for BioMedical Technology (BMTI), University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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96
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Otterness IG, Eckstein F. Women have thinner cartilage and smaller joint surfaces than men after adjustment for body height and weight. Osteoarthritis Cartilage 2007; 15:666-72. [PMID: 17321168 DOI: 10.1016/j.joca.2006.12.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2006] [Accepted: 12/03/2006] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Females have a higher incidence of knee osteoarthritis (OA) than males, but the reason for this is unclear. Here we examine the hypothesis that women have smaller joint surfaces than men, independent of weight and height, and thus encounter higher articular pressures that might contribute to the higher incidence of OA in the female knee. METHODS Forty healthy women and 57 men (21-39 years) with a body mass index of 16.8-32.8 were studied using magnetic resonance imaging. The right knee was scanned and proprietary software was used to determine the area of subchondral bone (cAB), mean cartilage thickness (ThC) and cartilage volume (VC) for all knee cartilage plates. Multilinear regression was used to correct the data for sex differences in height and weight. RESULTS cAB, ThC, and VC were larger in men than in women in all knee cartilage plates. Correction for height and weight differences between the sexes reduced but did not eliminate sex differences in these parameters. The cAB was a strong predictor of VC independent of sex, height and weight, but did not predict ThC. CONCLUSION Men have greater knee cABs, ThC and VC than females even after correction for height and weight. Nonetheless, estimated tibial and patellar pressures are similar between sexes and thus are unlikely to account for the sex differences in OA incidence.
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Affiliation(s)
- I G Otterness
- Division of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA.
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Gómez-Benito MJ, Moreo P, Pérez MA, Paseta O, García-Aznar JM, Barrios C, Doblaré M. A damage model for the growth plate: Application to the prediction of slipped capital epiphysis. J Biomech 2007; 40:3305-13. [PMID: 17606268 DOI: 10.1016/j.jbiomech.2007.04.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 04/10/2007] [Accepted: 04/29/2007] [Indexed: 11/18/2022]
Abstract
Despite slipped capital femoral epiphysis (SCFE) being one of the most common disorders of the adolescent hip, its early diagnosis is quite difficult. The main objective of this work is to apply an interface damage model to predict the failure of the bone-growth plate-bone interface. This model allows to evaluate the risk of development of SCFE and to investigate the range of mechanical properties of the physis that may cause slippage of the plate. This paper also studies the influence of different geometrical parameters and body weight of the patient on the development of SCFE. We have demonstrated, thanks to the proposed model, that higher physeal sloping and posterior sloping angles are associated to a higher probability of development of SCFE. In a similar way, increasing body weight results in a more probable slippage.
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Affiliation(s)
- M J Gómez-Benito
- Aragón Institute of Engineering Research (I3A), University of Zaragoza, CIBER-BNN Networking Center on Bioengineering, Biomaterials and Nanomedice ICS-Aragón Institute of Health Science, María de Luna s/n, 50018 Zaragoza, Spain.
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98
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Julkunen P, Kiviranta P, Wilson W, Jurvelin JS, Korhonen RK. Characterization of articular cartilage by combining microscopic analysis with a fibril-reinforced finite-element model. J Biomech 2006; 40:1862-70. [PMID: 17052722 DOI: 10.1016/j.jbiomech.2006.07.026] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Accepted: 07/16/2006] [Indexed: 11/22/2022]
Abstract
Load-bearing characteristics of articular cartilage are impaired during tissue degeneration. Quantitative microscopy enables in vitro investigation of cartilage structure but determination of tissue functional properties necessitates experimental mechanical testing. The fibril-reinforced poroviscoelastic (FRPVE) model has been used successfully for estimation of cartilage mechanical properties. The model includes realistic collagen network architecture, as shown by microscopic imaging techniques. The aim of the present study was to investigate the relationships between the cartilage proteoglycan (PG) and collagen content as assessed by quantitative microscopic findings, and model-based mechanical parameters of the tissue. Site-specific variation of the collagen network moduli, PG matrix modulus and permeability was analyzed. Cylindrical cartilage samples (n=22) were harvested from various sites of the bovine knee and shoulder joints. Collagen orientation, as quantitated by polarized light microscopy, was incorporated into the finite-element model. Stepwise stress-relaxation experiments in unconfined compression were conducted for the samples, and sample-specific models were fitted to the experimental data in order to determine values of the model parameters. For comparison, Fourier transform infrared imaging and digital densitometry were used for the determination of collagen and PG content in the same samples, respectively. The initial and strain-dependent fibril network moduli as well as the initial permeability correlated significantly with the tissue collagen content. The equilibrium Young's modulus of the nonfibrillar matrix and the strain dependency of permeability were significantly associated with the tissue PG content. The present study demonstrates that modern quantitative microscopic methods in combination with the FRPVE model are feasible methods to characterize the structure-function relationships of articular cartilage.
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Affiliation(s)
- Petro Julkunen
- Department of Physics, University of Kuopio, Kuopio, Finland.
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99
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Wilson W, Huyghe JM, van Donkelaar CC. A composition-based cartilage model for the assessment of compositional changes during cartilage damage and adaptation. Osteoarthritis Cartilage 2006; 14:554-60. [PMID: 16476555 DOI: 10.1016/j.joca.2005.12.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Accepted: 12/20/2005] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The composition of articular cartilage changes with progression of osteoarthritis. Since compositional changes are associated with changes in the mechanical properties of the tissue, they are relevant for understanding how mechanical loading induces progression. The objective of this study is to present a computational model of articular cartilage which enables to study the interaction between composition and mechanics. METHODS Our previously developed fibril-reinforced poroviscoelastic swelling model for articular cartilage was combined with our tissue composition-based model. In the combined model both the depth- and strain-dependencies of the permeability are governed by tissue composition. All local mechanical properties in the combined model are directly related to the local composition of the tissue, i.e., to the local amounts of proteoglycans and collagens and to tissue anisotropy. RESULTS Solely based on the composition of the cartilage, we were able to predict the equilibrium and transient response of articular cartilage during confined compression, unconfined compression, indentation and two different 1D-swelling tests, simultaneously. CONCLUSION Since both the static and the time-dependent mechanical properties have now become fully dependent on tissue composition, the model allows assessing the mechanical consequences of compositional changes seen during osteoarthritis without further assumptions. This is a major step forward in quantitative evaluations of osteoarthritis progression.
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Affiliation(s)
- W Wilson
- Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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