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Magdalena Müller-gerbl - One of the best experts on this subject based on the ideXlab platform.
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Mineral density and penetration strength of the Subchondral Bone Plate of the talar dome : high correlation and specific distribution patterns
The Journal of foot and ankle surgery : official publication of the American College of Foot and Ankle Surgeons, 2014Co-Authors: André Leumann, Victor Valderrabano, Sebastian Hoechel, Beat Göpfert, Magdalena Müller-gerblAbstract:The Subchondral Bone Plate plays an important role in stabilizing the osteochondral joint unit and in the pathomechanism of osteochondral lesions and osteoarthritis. The objective of the present study was to measure the mineral density distribution and Subchondral Bone Plate penetration strength of the talar dome joint facet to display and compare the specific distribution patterns. Ten cadaver specimens were used for computed tomography (CT) scans, from which densitograms were derived using CT-osteoabsorptiometry, and for mechanical indentation testing from which the penetration strength was obtained. Our results showed 2 different distribution patterns for mineral density and penetration strength. Of the 10 specimens, 6 (60%) showed bicentric maxima (anteromedially and anterolaterally), and 4 (40%) showed a monocentric maximum (either anteromedially or anterolaterally). A highly significant correlation (p < .0001) for both methods confirmed that the mineral density relied on local load characteristics. In conclusion, the biomechanical properties of the Subchondral Bone Plate of the talar dome joint facet showed specific distribution patterns. CT-osteoabsorptiometry is a reliable method to display the mineral density distribution noninvasively. We recommend CT-osteoabsorptiometry for noninvasive analysis of the biomechanical properties of the Subchondral Bone Plate in osteochondral joint reconstruction and the prevention and treatment of osteoarthritis and osteochondral lesions.
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Changes of density distribution of the Subchondral Bone Plate after supramalleolar osteotomy for valgus ankle osteoarthritis
Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 2014Co-Authors: Christian Egloff, Jochen Paul, Geert Pagenstert, Patrick Vavken, Beat Hintermann, Victor Valderrabano, Magdalena Müller-gerblAbstract:CT-osteoabsorptiometry (CT-OAM) has been used to visualize Subchondral Bone Plate density distribution regarding to its mineralization. The purpose of this study was to display and analyze the density distribution of the Subchondral Bone Plate before and after supramalleolar realignment osteotomies. We retrospectively analysed pre- and postoperative CT images of nine consecutive patients with post-traumatic unilateral valgus ankle OA. The distribution charts of CT-OAM scans were quantitatively analyzed for Subchondral Bone Plate density distribution. VAS for pain and the Tegner activity scale were used to assess clinical outcome. At a mean follow-up of 20 ± 5.6 months (range 13–27), we observed a significant pre- to postoperative decrease of the mean high-density area ratio in tibia (lateral and posterior area) (p ≤ 0.05) and the talus (lateral area) (p ≤ 0.05). Pairwise comparison between the pre- and postoperative mineralization at the articular surface showed a significant decrease of the high-density area ratio for the tibia and the talus. The VAS decreased from 6.2 ± 0.9 pre- to 2.8 ± 0.9 postoperatively (p = 0.027), and the Tegner score inclined from 4.5 ± 1.1 preoperatively to 5.3 ± 0.7 after surgery (p = 0.082). The tibial and talar Subchondral Bone Plate density, regarding to its mineralization, decreased after supramalleolar medial closing wedge osteotomy in patients with valgus ankle OA. The results of this study suggest that realignment surgery may decrease peak Bone density areas corresponding to the alignment correction and contribute to a homogenization of the Subchondral Bone Plate mineralization. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1356–1361, 2014. Level of evidence Level IV, Case series.
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The subtalar and talonavicular joints: a way to access the long-term load intake using conventional CT-data
Surgical and radiologic anatomy : SRA, 2013Co-Authors: Fabian Mueller, Dieter Wirz, Sebastian Hoechel, Joerg Klaws, Magdalena Müller-gerblAbstract:Purpose The aim of this study was to investigate the distribution of density of the Subchondral Bone Plate within the articular surfaces of the subtalar and talonavicular joint regarding to its mineralisation and to verify whether a correlation to the mechanical Bone strength exists.
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The human hip joint and its long-term load intake--how x-ray density distribution mirrors Bone strength.
Hip international : the journal of clinical and experimental research on hip pathology and therapy, 2013Co-Authors: Sebastian Hoechel, Dieter Wirz, Marc Alder, Magdalena Müller-gerblAbstract:The aim of this study was to gain information about the topographical distribution of the mechanical strength of the Subchondral Bone Plate of the hip joint and evaluate the correlation to its density distribution. Our intention was to describe a method of visualising and monitoring the long-term load intake of the hip using conventional CT-data in a way which might be applied in clinical practice. We examined the lunate surface of the acetabulum (facies lunata) and femoral head in 25 cases, looking at the density of the Subchondral Bone Plate by computed tomography osteoabsorptiometry (CT-OAM) and determined its mechanical strength by indentation testing using an osteo-penetrometer. The resulting distribution patterns were matched and statistically analysed, showing an inhomogeneous but regular and reproducible distribution of mineralisation and mechanical strength throughout the joint surface. Maximal density was found anterosuperiorly and near the rim of the facies lunata and in the superior area of the femoral head. For each specimen a correlation of density and strength (r2 = 0.77 - 0.97) was found (p>0.01). The density distribution pattern shown by CT-OAM allows conclusions to be drawn about the distribution of strength and therefore the long term load intake within the Subchondral Bone Plate of the hip. Using conventional CT-data, the method can be used in the clinical setting for evaluation and monitoring.
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A comparison of Subchondral Bone mineralization between the glenoid cavity and the humeral head on 57 cadaverous shoulder joints
Surgical and Radiologic Anatomy, 2013Co-Authors: Marko Kraljević, Valentin Zumstein, Rolf Hügli, Magdalena Müller-gerblAbstract:Purpose Mineralization distribution of the Subchondral Bone Plate can be used as a marker for long-term stress distribution in diarthrodial joints. Severe injuries or pathological changes of the glenohumeral joint often end in osteoarthritis, where shoulder arthroplasty has become the treatment of choice. The computed tomography osteoabsorptiometry (CT-OAM) is a non-invasive method to determine the distribution of the mineralization of the Subchondral Bone Plate in vivo, which is an important factor concerning the implantation of orthopedic endoprostheses. The aim of this study was to investigate the mineralization of both joint partners of the glenohumeral joint and to compare them with each other. Methods The distribution of the mineralization of the Subchondral Bone Plate of 57 shoulder specimens was determined by means of CT-OAM. To evaluate a correlation between age and localization of Subchondral mineralization maxima, the Chi-square test correlation test was applied. Results Forty-nine glenoid cavities (86 %) showed a bicentric mineralization distribution pattern with anterior and posterior maxima, only 8 glenoid cavities (14 %) revealed a monocentric mineralization pattern with anterior maxima. Forty-five humeral heads (79 %) showed a bicentric distribution pattern with anterior and posterior maxima, 12 humeral heads (21 %) could be classified as monocentric with a centro-posterior pronounced maximum. Conclusions We could demonstrate that stress distribution in both joint partners of the glenohumeral joint is inhomogeneous and characteristically bicentric due to the physiological incongruity. Monocentric mineralization patterns can result as a cause of age-related loss of incongruity.
Henning Madry - One of the best experts on this subject based on the ideXlab platform.
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Advancement of the Subchondral Bone Plate in Translational Models of Osteochondral Repair: Implications for Tissue Engineering Approaches.
Tissue engineering. Part B Reviews, 2015Co-Authors: Patrick Orth, Henning MadryAbstract:Subchondral Bone Plate advancement is of increasing relevance for translational models of osteochondral repair in tissue engineering (TE). Especially for therapeutic TE approaches, a basic scientific knowledge of its chronological sequence, possible etiopathogenesis, and clinical implications are indispensable. This review summarizes the knowledge on this topic gained from a total of 31 translational investigations, including 1009 small and large animals. Experimental data indicate that the advancement of the Subchondral Bone Plate frequently occurs during the spontaneous repair of osteochondral defects and following established articular cartilage repair approaches for chondral lesions such as marrow stimulation and TE-based strategies such as autologous chondrocyte implantation. Importantly, this Subchondral Bone reaction proceeds in a defined chronological and spatial pattern, reflecting both endochondral ossification and intramembranous Bone formation. Subchondral Bone Plate advancement arises earlier in small animals and defects, but is more pronounced at the long term in large animals. Possible etiopathologies comprise a disturbed Subchondral Bone/articular cartilage crosstalk and altered biomechanical conditions or neovascularization. Of note, no significant correlation was found so far between Subchondral Bone Plate advancement and articular cartilage repair. This evidence from translational animal models adverts to an increasing awareness of this previously underestimated pathology. Future research will shed more light on the advancement of the Subchondral Bone Plate in TE models of cartilage repair.
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Effect of open wedge high tibial osteotomy on the lateral tibiofemoral compartment in sheep. Part III: analysis of the microstructure of the Subchondral Bone and correlations with the articular cartilage and meniscus
Knee surgery sports traumatology arthroscopy : official journal of the ESSKA, 2014Co-Authors: Raphaela Ziegler, Magali Cucchiarini, Lars Goebel, Roland Seidel, Dietrich Pape, Henning MadryAbstract:Purpose First, to evaluate whether medial open wedge high tibial osteotomy (HTO) induces alterations of the microstructure of the lateral tibial Subchondral Bone Plate of sheep. Second, to test the hypothesis that specific correlations exist between topographical structural alterations of the Subchondral Bone, the cartilage and the lateral meniscus.
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temporal and spatial migration pattern of the Subchondral Bone Plate in a rabbit osteochondral defect model
Osteoarthritis and Cartilage, 2012Co-Authors: Patrick Orth, Stefan Graber, Gunter Kaul, Magali Cucchiarini, Dieter Kohn, Henning MadryAbstract:Summary Objective Upward migration of the Subchondral Bone Plate is associated with osteochondral repair. The aim of this study was to quantitatively monitor the sequence of Subchondral Bone Plate advancement in a lapine model of spontaneous osteochondral repair over a 1-year period and to correlate these findings with articular cartilage repair. Design Standardized cylindrical osteochondral defects were created in the rabbit trochlear groove. Subchondral Bone reconstitution patterns were identified at five time points. Migration of the Subchondral Bone Plate and areas occupied by osseous repair tissue were determined by histomorphometrical analysis. Tidemark formation and overall cartilage repair were correlated with the histomorphometrical parameters of the Subchondral Bone. Results The Subchondral Bone reconstitution pattern was cylindrical at 3 weeks, infundibuliform at 6 weeks, plane at 4 and 6 months, and hypertrophic after 1 year. At this late time point, the osteochondral junction advanced 0.19 [95% confidence intervals (CI) 0.10–0.30] mm above its original level. Overall articular cartilage repair was significantly improved by 4 and 6 months but degraded after 1 year. Subchondral Bone Plate migration correlated with tidemark formation ( r = 0.47; P r = 0.11; P > 0.44). Conclusions The Subchondral Bone Plate is reconstituted in a distinct chronological order. The lack of correlation suggests that articular cartilage repair and Subchondral Bone reconstitution proceed at a different pace and that the advancement of the Subchondral Bone Plate is not responsible for the diminished articular cartilage repair in this model.
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The basic science of the Subchondral Bone
Knee Surgery Sports Traumatology Arthroscopy, 2010Co-Authors: Henning Madry, C. Niek Dijk, Magdalena Mueller-gerblAbstract:In the past decades, considerable efforts have been made to propose experimental and clinical treatments for articular cartilage defects. Yet, the problem of cartilage defects extending deep in the underlying Subchondral Bone has not received adequate attention. A profound understanding of the basic anatomic aspects of this particular site, together with the pathophysiology of diseases affecting the Subchondral Bone is the key to develop targeted and effective therapeutic strategies to treat osteochondral defects. The Subchondral Bone consists of the Subchondral Bone Plate and the subarticular spongiosa. It is separated by the cement line from the calcified zone of the articular cartilage. A variable anatomy is characteristic for the Subchondral region, reflected in differences in thickness, density, and composition of the Subchondral Bone Plate, contour of the tidemark and cement line, and the number and types of channels penetrating into the calcified cartilage. This review aims at providing insights into the anatomy, morphology, and pathology of the Subchondral Bone. Individual diseases affecting the Subchondral Bone, such as traumatic osteochondral defects, osteochondritis dissecans, osteonecrosis, and osteoarthritis are also discussed. A better knowledge of the basic science of the Subchondral region, together with additional investigations in animal models and patients may translate into improved therapies for articular cartilage defects that arise from or extend into the Subchondral Bone.
Joerg Mika - One of the best experts on this subject based on the ideXlab platform.
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Surgical Preparation for Articular Cartilage Regeneration in the Osteoarthritic Knee Joint.
Cartilage, 2016Co-Authors: Joerg Mika, Thomas O. Clanton, Catherine G. Ambrose, Raimund W. KinneAbstract:Purpose:Autologous chondrocyte implantation (ACI) is a treatment option even in early osteoarthritis (OA). Surgical preparation for ACI should avoid penetration of the Subchondral Bone Plate to prevent hemorrhage, fibrin clot formation, and subsequent activation of the inflammatory response.Hypothesis:Current surgical procedures with ring curettes preserve the integrity of the Subchondral Bone Plate, even in patients with OA.Methods:Subchondral femoral Bone Plates (n = 40) of OA knees undergoing total knee arthroplasty were prepared in vivo using standard, non–brute-force debridement for ACI. To approach regular wear/early OA, only cartilage with maximally grade 3A International Cartilage Repair Society score was prepared. Effects were analyzed by light microscopy.Results:In 87.5% of the specimens (35/40), standard debridement did not violate the tide mark, except for occasional minor openings with a smooth edge (diameter approximately 20 µm). In contrast, 5/40 samples (12.5%) showed one large area with a...
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surgical preparation for articular cartilage regeneration without penetration of the Subchondral Bone Plate in vitro and in vivo studies in humans and sheep
American Journal of Sports Medicine, 2011Co-Authors: Joerg Mika, Thomas O. Clanton, Catherine G. Ambrose, David Pretzel, Gerlind Schneider, Raimund W. KinneAbstract:Background: To prevent hemorrhage, fibrin clot formation, and subsequent activation of the inflammatory response, surgical preparation for articular cartilage regeneration should avoid penetration of the Subchondral Bone Plate.Hypothesis: Current surgical procedures with ring curettes do not violate the Subchondral Bone Plate.Study Design: Controlled laboratory study.Methods: The Subchondral Bone Plates of normal human (n = 5) or sheep (n = 12) cadaver femoral condyles were prepared in vitro using either traditional debridement for autologous chondrocyte implantation/transplantation (ACI/ACT) or a modified approach aimed at deliberately violating the Subchondral Bone Plate (ie, brute force). Effects were analyzed by light microscopy. In addition, Subchondral Bone Plates of osteoarthritic (OA) human knees undergoing total knee arthroplasty (n = 5) or normal sheep knees (n = 5) were prepared in vivo. To approximate normal/regular wear, in humans, only OA samples with maximally grade 3A (International Cartil...
Dieter Wirz - One of the best experts on this subject based on the ideXlab platform.
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The subtalar and talonavicular joints: a way to access the long-term load intake using conventional CT-data
Surgical and radiologic anatomy : SRA, 2013Co-Authors: Fabian Mueller, Dieter Wirz, Sebastian Hoechel, Joerg Klaws, Magdalena Müller-gerblAbstract:Purpose The aim of this study was to investigate the distribution of density of the Subchondral Bone Plate within the articular surfaces of the subtalar and talonavicular joint regarding to its mineralisation and to verify whether a correlation to the mechanical Bone strength exists.
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The human hip joint and its long-term load intake--how x-ray density distribution mirrors Bone strength.
Hip international : the journal of clinical and experimental research on hip pathology and therapy, 2013Co-Authors: Sebastian Hoechel, Dieter Wirz, Marc Alder, Magdalena Müller-gerblAbstract:The aim of this study was to gain information about the topographical distribution of the mechanical strength of the Subchondral Bone Plate of the hip joint and evaluate the correlation to its density distribution. Our intention was to describe a method of visualising and monitoring the long-term load intake of the hip using conventional CT-data in a way which might be applied in clinical practice. We examined the lunate surface of the acetabulum (facies lunata) and femoral head in 25 cases, looking at the density of the Subchondral Bone Plate by computed tomography osteoabsorptiometry (CT-OAM) and determined its mechanical strength by indentation testing using an osteo-penetrometer. The resulting distribution patterns were matched and statistically analysed, showing an inhomogeneous but regular and reproducible distribution of mineralisation and mechanical strength throughout the joint surface. Maximal density was found anterosuperiorly and near the rim of the facies lunata and in the superior area of the femoral head. For each specimen a correlation of density and strength (r2 = 0.77 - 0.97) was found (p>0.01). The density distribution pattern shown by CT-OAM allows conclusions to be drawn about the distribution of strength and therefore the long term load intake within the Subchondral Bone Plate of the hip. Using conventional CT-data, the method can be used in the clinical setting for evaluation and monitoring.
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cartilage stiffness and Subchondral Bone Plate strength of the human patella
Journal of Biomechanics, 2012Co-Authors: Sarah Ronken, Dieter Wirz, Sebastian Hoechel, Magdalena MullergerblAbstract:The mechanical strength of the Subchondral Bone Plate and cartilage stiffness is widely investigated. Bone is an adaptive tissue which restructures itself when the loading pattern changes. A correlation exists between the mechanical strength and the Subchondral Bone Plate mineralization [Zumstein, 2011]. Since cartilage absorbs and distributes the applied load to reduce localized stress concentrations in the underlying Bone, it is likely that the Bone remodels when the mechanical properties of cartilage change. The aim of this study was to look at the correlation between mechanical properties of cartilage and the Subchondral Bone Plate underneath. We hypothesise that when the cartilage transfers less stress to the Bone, it will weaken, whereas an increase of stress transfer through the cartilage will strengthen the Subchondral Bone Plate.
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mechanical strength and mineralisation of the Subchondral Bone Plate of the human patella
Journal of Biomechanics, 2012Co-Authors: Sebastian Hoechel, Dieter Wirz, Magdalena MullergerblAbstract:s / Osteoarthritis and Cartilage 20 (2012) S54–S296 S113 211 MECHANICAL STRENGTH AND MINERALISATION OF THE Subchondral Bone Plate OF THE HUMAN PATELLA S. Hoechel , D. Wirz , M. Muller-Gerbl . Anatomical Inst., Univ. of Basel, Basel, Switzerland; 2 Lab. of Biomechanics & Biocalorimetry, Basel, Switzerland Purpose: The Subchondral Bone Plate is a dynamic component that shows a functional adaptation to long-term loading history. This can be seen in the density distribution of the Subchondral Bone Plate. In the human patella findings obtained with the photoelastic model show stress maxima in the lateral facet, which agrees with results showing the region ofmaximumBone density to be constantly found on the lateral facet. The visualization of the density distribution patterns has been generated with the help of CT-osteoabsorptiometry (CT-OAM), a method for densitometric evaluation of CT-scans according to the Hounsfield units (HU). Recent tests on human humeral heads showed that the density distribution of the Subchondral Bone Plate correlates to the mechanical strength of it. As for the human patella, structural studies on Subchondral Bone strength only focussed on the Subchondral trabecular Bone, the Subchondral Bone Plate has not been addressed. The aim of this study was to look at the density distribution of the human patella in correlation to the mechanical strength of the Subchondral Bone Plate.We hypothesise that themineralisation shownwith CT-OAM and the mechanical strength of the Subchondral Bone Plate correlate. Methods: 20 patellae were collected from human cadavers, and measurements were performed at 34 coordinate points for each. To visualize the density distribution patterns, the CT data of the patellae were evaluated with the help of ANALYSE 8.1 (Mayo Foundation, Rochester, MN, USA). Using a “maximum intention projection”, the maximal dense value of the Subchondral Bone Plate was projected to the surface and presented in a false-colour diagramassigning false colours to every 100HU (Fig. 1A). Densitymeasurementswere taken at the defined coordinate points and recorded in a standardized grid system. To determine the mechanical strength, an indentation test machine (Synergie 100, MTS Systems, Eden Prairie, MN; 2 kN loadcell) was used. A steel needle (o1⁄4 1.3mm) created a standardised hole of 7 mm depth (1mm/sec) at the same coordinate point the density measurement was made. The penetration forces as well as the maximum force were recorded in a standardized grid systemwith its corresponding coordinates and visualised (Fig. 1B). Linear regression was used to evaluate statistical correlations (Fig. 2). Results: We show that neither the mineralisation nor the mechanical strength of the Subchondral Bone Plate is distributed homogeneously on the patella. The maximum values consistently showed to be on the lateral facet (Fig. 1). A linear correlation was found between the density distribution and the mechanical Subchondral Bone Plate strength (Fig. 2). The coefficient of correlation (range: 0.89 to 0.97; mean 0.92) was significant. Conclusions: A direct relationship between the Subchondral Bone Plate density and the mechanical strength could be expected. Since the Subchondral Bone Plate adapts to its mechanical needs, areas of high load transmission increase the strength of the Subchondral Bone Plate by osteoblastic calcium deposition. This increase in calcium is presented in the density distribution patterns. The correlation of mineralisation and mechanical strength makes CT-OAM a valuable tool to determine the strength of the Subchondral Bone Plate in vivo. 212 MODULATION OF GENE EXPRESSION IN HUMAN Subchondral Bone CELLS CO-CULTURED WITH HUMAN ARTICULAR CHONDROCYTES. E.F. Burguera, A. Vela-Anero, F.J. Blanco. INIBIC-CHUAC, Tissue Engineering and Cellular Therapy Group (CBBTC-CHUAC), CIBER-BBN/ISCIII, A Coruna,
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Density and strength distribution in the human Subchondral Bone Plate of the patella.
International Orthopaedics, 2012Co-Authors: Sebastian Hoechel, Dieter Wirz, Magdalena Müller-gerblAbstract:Purpose The aim of this study was to map the strength distribution of the human patella and correlate it to the Subchondral Bone Plate density obtained by means of computed tomographyosteoabsorptiometry (CT-OAM).
Magdalena Mullergerbl - One of the best experts on this subject based on the ideXlab platform.
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cartilage stiffness and Subchondral Bone Plate strength of the human patella
Journal of Biomechanics, 2012Co-Authors: Sarah Ronken, Dieter Wirz, Sebastian Hoechel, Magdalena MullergerblAbstract:The mechanical strength of the Subchondral Bone Plate and cartilage stiffness is widely investigated. Bone is an adaptive tissue which restructures itself when the loading pattern changes. A correlation exists between the mechanical strength and the Subchondral Bone Plate mineralization [Zumstein, 2011]. Since cartilage absorbs and distributes the applied load to reduce localized stress concentrations in the underlying Bone, it is likely that the Bone remodels when the mechanical properties of cartilage change. The aim of this study was to look at the correlation between mechanical properties of cartilage and the Subchondral Bone Plate underneath. We hypothesise that when the cartilage transfers less stress to the Bone, it will weaken, whereas an increase of stress transfer through the cartilage will strengthen the Subchondral Bone Plate.
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mechanical strength and mineralisation of the Subchondral Bone Plate of the human patella
Journal of Biomechanics, 2012Co-Authors: Sebastian Hoechel, Dieter Wirz, Magdalena MullergerblAbstract:s / Osteoarthritis and Cartilage 20 (2012) S54–S296 S113 211 MECHANICAL STRENGTH AND MINERALISATION OF THE Subchondral Bone Plate OF THE HUMAN PATELLA S. Hoechel , D. Wirz , M. Muller-Gerbl . Anatomical Inst., Univ. of Basel, Basel, Switzerland; 2 Lab. of Biomechanics & Biocalorimetry, Basel, Switzerland Purpose: The Subchondral Bone Plate is a dynamic component that shows a functional adaptation to long-term loading history. This can be seen in the density distribution of the Subchondral Bone Plate. In the human patella findings obtained with the photoelastic model show stress maxima in the lateral facet, which agrees with results showing the region ofmaximumBone density to be constantly found on the lateral facet. The visualization of the density distribution patterns has been generated with the help of CT-osteoabsorptiometry (CT-OAM), a method for densitometric evaluation of CT-scans according to the Hounsfield units (HU). Recent tests on human humeral heads showed that the density distribution of the Subchondral Bone Plate correlates to the mechanical strength of it. As for the human patella, structural studies on Subchondral Bone strength only focussed on the Subchondral trabecular Bone, the Subchondral Bone Plate has not been addressed. The aim of this study was to look at the density distribution of the human patella in correlation to the mechanical strength of the Subchondral Bone Plate.We hypothesise that themineralisation shownwith CT-OAM and the mechanical strength of the Subchondral Bone Plate correlate. Methods: 20 patellae were collected from human cadavers, and measurements were performed at 34 coordinate points for each. To visualize the density distribution patterns, the CT data of the patellae were evaluated with the help of ANALYSE 8.1 (Mayo Foundation, Rochester, MN, USA). Using a “maximum intention projection”, the maximal dense value of the Subchondral Bone Plate was projected to the surface and presented in a false-colour diagramassigning false colours to every 100HU (Fig. 1A). Densitymeasurementswere taken at the defined coordinate points and recorded in a standardized grid system. To determine the mechanical strength, an indentation test machine (Synergie 100, MTS Systems, Eden Prairie, MN; 2 kN loadcell) was used. A steel needle (o1⁄4 1.3mm) created a standardised hole of 7 mm depth (1mm/sec) at the same coordinate point the density measurement was made. The penetration forces as well as the maximum force were recorded in a standardized grid systemwith its corresponding coordinates and visualised (Fig. 1B). Linear regression was used to evaluate statistical correlations (Fig. 2). Results: We show that neither the mineralisation nor the mechanical strength of the Subchondral Bone Plate is distributed homogeneously on the patella. The maximum values consistently showed to be on the lateral facet (Fig. 1). A linear correlation was found between the density distribution and the mechanical Subchondral Bone Plate strength (Fig. 2). The coefficient of correlation (range: 0.89 to 0.97; mean 0.92) was significant. Conclusions: A direct relationship between the Subchondral Bone Plate density and the mechanical strength could be expected. Since the Subchondral Bone Plate adapts to its mechanical needs, areas of high load transmission increase the strength of the Subchondral Bone Plate by osteoblastic calcium deposition. This increase in calcium is presented in the density distribution patterns. The correlation of mineralisation and mechanical strength makes CT-OAM a valuable tool to determine the strength of the Subchondral Bone Plate in vivo. 212 MODULATION OF GENE EXPRESSION IN HUMAN Subchondral Bone CELLS CO-CULTURED WITH HUMAN ARTICULAR CHONDROCYTES. E.F. Burguera, A. Vela-Anero, F.J. Blanco. INIBIC-CHUAC, Tissue Engineering and Cellular Therapy Group (CBBTC-CHUAC), CIBER-BBN/ISCIII, A Coruna,
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mineralisation and mechanical strength of the Subchondral Bone Plate of the inferior tibial facies
Surgical and Radiologic Anatomy, 2009Co-Authors: H. Mühlhofer, Y. Ercan, S. Drews, M. Matsuura, J. Meissner, U. Linsenmaier, R. Putz, Magdalena MullergerblAbstract:The implantation of total ankle prosthesis is one of the most challenging operations in orthopaedic surgery. The main problem that surgeons face is the fixation of the total ankle prosthesis on the tibial side. The Subchondral Bone Plate of the distal tibia is considered the strongest region on the inferior tibial facies. Based on information about the mineralisation of the Subchondral Bone Plate, conclusions can be made concerning the mechanical stress, age-related changes, post-surgical biomechanical situations and regions of fixation. The aim of this study was to determine the correlation between the mineralisation of the Subchondral Bone Plate and the topical mechanical strength. By means of CT-osteoabsorptiometry, the distribution of mineralisation in the Subchondral Bone Plate in 18 distal Tibiae was investigated. After removal of the cartilage of the facies articularis inferior, the mechanical strength of the joint surface was measured with an indentation apparatus. The linear regression of the mineralisation density and the maximal mechanical strength to penetrate the Subchondral Bone Plate was determined. Our data showed a coefficient of determination between 0.75 and 0.97 and a coefficient of correlation between 0.86 and 0.97. The T test showed significance (P < 0.05). Furthermore, we demonstrated a bicentric distribution of mineralisation patterns. The maximal mineralisation was found ventromedially and mediolaterally on the joint surface. Our study shows good correlation of mineralisation and mechanical property of the inferior tibial facies. Therefore, as the results provide information on the topographical distribution of Bone quality, they could be useful for the development of new fixation methods for total ankle prosthesis.
