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Philippe Pourcelot - One of the best experts on this subject based on the ideXlab platform.
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Correlations between mean echogenicity and material properties of normal and diseased equine superficial digital flexor Tendons : an in vitro segmental approach
Journal of Biomechanics, 2005Co-Authors: Nathalie Crevier-denoix, Y. Ruel, C. Dardillat, Hassen Jerbi, M. Sanaa, C. Collobert-laugier, X. Ribot, Jean-marie Denoix, Philippe PourcelotAbstract:The objective of this study was to test the hypothesis that Tendon echogenicity is associated with the material properties of the corresponding Tendon site, especially in case of lesions, due to local changes in Tendon matrix composition. Four normal and nine spontaneously injured equine superficial digital flexor Tendons (SDFT) were isolated then ultrasonographically examined under tension, in a special device placed in a water bath. Ultrasonographic transversal images (7.5 MHz linear transducer) of five segments along each Tendon were digitized, and analyzed in order to measure the mean cross-sectional area (MCSA) and mean echogenicity (ME) of each segment. The Tendons were then tested in traction until rupture in a testing machine. For each segment, stress and strain were determined throughout the test, and the elastic modulus (EM) was evaluated. The Tendon lesions were also documented by histology. No correlation was found between ME and the material properties of normal Tendon segments. At the rupture sites of the nine diseased Tendons, ME was positively correlated with maximal stress and EM, whereas no correlation was demonstrated with maximal strain. Besides, a positive correlation was demonstrated between ME and both MCSA and EM, when the three metacarpal segments of the diseased Tendons were considered. Although ME gives only rough information about Tendon matrix structure, it does show, under these in vitro conditions, significant correlations with material properties of pathological Tendon segments, which may improve the functional significance and therefore the pronostic value of the ultrasonographic examination of Tendon lesions.
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A non-invasive method of Tendon force measurement
Journal of Biomechanics, 2005Co-Authors: Philippe Pourcelot, Marielle Defontaine, Bérangère Ravary, Mickael Lematre, Nathalie Crevier-denoixAbstract:The ability to measure the forces exerted in vivo on Tendons and, consequently, the forces produced by muscles on Tendons, offers a unique opportunity to investigate questions in disciplines as varied as physiology, biomechanics, orthopaedics and neuroscience. Until now, Tendon loads could be assessed directly only by means of invasive sensors implanted within or attached to these collagenous structures. This study shows that the forces acting on Tendons can be measured, in a non-invasive way, from the analysis of the propagation of an acoustic wave. Using the equine superficial digital flexor Tendon as a model, it is demonstrated that the velocity of an ultrasonic wave propagating along the main axis of a Tendon increases with the force applied to this Tendon. Furthermore, we show that this velocity measurement can be performed even in the presence of skin overlying the Tendon. To validate this measurement technique in vivo, the ultrasonic velocity plots obtained in the Achilles Tendon at the walk were compared to the loads plots reported by other authors using invasive transducers.
Nathalie Crevier-denoix - One of the best experts on this subject based on the ideXlab platform.
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Correlations between mean echogenicity and material properties of normal and diseased equine superficial digital flexor Tendons : an in vitro segmental approach
Journal of Biomechanics, 2005Co-Authors: Nathalie Crevier-denoix, Y. Ruel, C. Dardillat, Hassen Jerbi, M. Sanaa, C. Collobert-laugier, X. Ribot, Jean-marie Denoix, Philippe PourcelotAbstract:The objective of this study was to test the hypothesis that Tendon echogenicity is associated with the material properties of the corresponding Tendon site, especially in case of lesions, due to local changes in Tendon matrix composition. Four normal and nine spontaneously injured equine superficial digital flexor Tendons (SDFT) were isolated then ultrasonographically examined under tension, in a special device placed in a water bath. Ultrasonographic transversal images (7.5 MHz linear transducer) of five segments along each Tendon were digitized, and analyzed in order to measure the mean cross-sectional area (MCSA) and mean echogenicity (ME) of each segment. The Tendons were then tested in traction until rupture in a testing machine. For each segment, stress and strain were determined throughout the test, and the elastic modulus (EM) was evaluated. The Tendon lesions were also documented by histology. No correlation was found between ME and the material properties of normal Tendon segments. At the rupture sites of the nine diseased Tendons, ME was positively correlated with maximal stress and EM, whereas no correlation was demonstrated with maximal strain. Besides, a positive correlation was demonstrated between ME and both MCSA and EM, when the three metacarpal segments of the diseased Tendons were considered. Although ME gives only rough information about Tendon matrix structure, it does show, under these in vitro conditions, significant correlations with material properties of pathological Tendon segments, which may improve the functional significance and therefore the pronostic value of the ultrasonographic examination of Tendon lesions.
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A non-invasive method of Tendon force measurement
Journal of Biomechanics, 2005Co-Authors: Philippe Pourcelot, Marielle Defontaine, Bérangère Ravary, Mickael Lematre, Nathalie Crevier-denoixAbstract:The ability to measure the forces exerted in vivo on Tendons and, consequently, the forces produced by muscles on Tendons, offers a unique opportunity to investigate questions in disciplines as varied as physiology, biomechanics, orthopaedics and neuroscience. Until now, Tendon loads could be assessed directly only by means of invasive sensors implanted within or attached to these collagenous structures. This study shows that the forces acting on Tendons can be measured, in a non-invasive way, from the analysis of the propagation of an acoustic wave. Using the equine superficial digital flexor Tendon as a model, it is demonstrated that the velocity of an ultrasonic wave propagating along the main axis of a Tendon increases with the force applied to this Tendon. Furthermore, we show that this velocity measurement can be performed even in the presence of skin overlying the Tendon. To validate this measurement technique in vivo, the ultrasonic velocity plots obtained in the Achilles Tendon at the walk were compared to the loads plots reported by other authors using invasive transducers.
Hans T M Van Schie - One of the best experts on this subject based on the ideXlab platform.
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ultrasonographic tissue characterisation of human achilles Tendons quantification of Tendon structure through a novel non invasive approach
British Journal of Sports Medicine, 2010Co-Authors: Hans T M Van Schie, R J De Vos, S De Jonge, Erwi M Akke, M P Heijboe, J A Verhaa, Johannes L Tol, Harrie WeinansAbstract:Objective To assess whether three-dimensional imaging of the Achilles Tendon by ultrasonographic tissue characterisation (UTC) can differentiate between symptomatic and asymptomatic Tendons. Design Case-control study. Setting Sports Medical Department of the Hague Medical Centre. Patients Twenty-six Tendons from patients with chronic midportion Achilles tendinopathy were included. The “matched” control group consisted of 26 asymptomatic Tendons. Interventions Symptomatic and asymptomatic Tendons were scanned using the UTC procedure. One researcher performed the ultrasonographic data collection. These blinded data were randomised, and outcome measures were determined by two independent observers. Main outcome measurements The raw ultrasonographic images were analysed with a customdesigned algorithm that quantifi es the three-dimensional stability of echo patterns, qua intensity and distribution over contiguous transverse images. This threedimensional stability was related to Tendon structure in previous studies. UTC categorises four different echotypes that represent (I) highly stable; (II) medium stable; (III) highly variable and (IV) constantly low intensity and variable distribution. The percentages of echo-types were calculated, and the maximum Tendon thickness was measured. Finally, the inter-observer reliability of UTC was determined. Results Symptomatic Tendons showed less pixels in echo-types I and II than asymptomatic Tendons (51.5% vs 76.6%, p<0.001), thus less three-dimensional stability of the echo pattern. The mean maximum Tendon thickness was 9.2 mm in the symptomatic group and 6.8 mm in the asymptomatic group (p<0.001). The Intraclass Correlation Coeffi cient (ICC) for the interobserver reliability of determining the echo-types I+II was 0.95. The ICC for Tendon thickness was 0.84. Conclusion UTC can quantitatively evaluate Tendon structure and thereby discriminate symptomatic and asymptomatic Tendons. As such, UTC might be useful to monitor treatment protocols.
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effects of platelet rich plasma on the quality of repair of mechanically induced core lesions in equine superficial digital flexor Tendons a placebo controlled experimental study
Journal of Orthopaedic Research, 2009Co-Authors: G Osch, Hans T M Van Schie, Mark W De Groo, Jennifer A. Cadby, Chris H A Van De Les, Ab Arneveld, Rene P Van WeereAbstract:Tendon injuries are notorious for their slow and functionally inferior healing. Intratendinous application of platelet-rich plasma (PRP) has been reported to stimulate the repair process of Tendon injuries, but there is little conclusive evidence for its effectiveness. A placebo-controlled experimental trial was performed to test the hypothesis that a single intratendinous PRP treatment enhances the quality of Tendon repair, as evidenced by improved biochemical, biomechanical, and histological tissue properties. In six horses, Tendon lesions were created surgically in the Superficial Digital Flexor Tendons (SDFT) of both front limbs, one of which was treated with PRP and the other with saline. After 24 weeks, the Tendons were harvested for biochemical, biomechanical, and histological evaluations. Collagen, glycosaminoglycan, and DNA content (cellularity) was higher in PRP-treated Tendons (p = 0.039, 0.038, and 0.034, respectively). The repair tissue in the PRP group showed a higher strength at failure (p = 0.021) and Elastic Modulus (p = 0.019). Histologically, PRP-treated Tendons featured better organization of the collagen network (p = 0.031) and signs of increased metabolic activity (p = 0.031). It was concluded that PRP increases metabolic activity and seems to advance maturation of repair tissue over nontreated experimentally induced Tendon lesions, which suggests that PRP might be beneficial in the treatment of clinical Tendon injuries. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:211–217, 2010
Daw M Ellio - One of the best experts on this subject based on the ideXlab platform.
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continuous shear wave elastography a new method to measure viscoelastic properties of Tendons in vivo
Ultrasound in Medicine and Biology, 2015Co-Authors: Daniel H Cortes, Stephe M Suydam, Karin Gravare Silbernagel, Thomas S Uchana, Daw M EllioAbstract:Viscoelastic mechanical properties are frequently altered after Tendon injuries and during recovery. Therefore, non-invasive measurements of shear viscoelastic properties may help evaluate Tendon recovery and compare the effectiveness of different therapies. The objectives of this study were to describe an elastography method for measuring localized viscoelastic properties of Tendons and to discuss the initial results in healthy and injured human Achilles and semitendinosus Tendons. The technique used an external actuator to generate the shear waves in the Tendon at different frequencies and plane wave imaging to measure shear wave displacements. For each of the excitation frequencies, maps of direction-specific wave speeds were calculated using local frequency estimation. Maps of viscoelastic properties were obtained using a pixel-wise curve fit of wave speed and frequency. The method was validated by comparing measurements of wave speed in agarose gels with those obtained using magnetic resonance elastography. Measurements in human healthy Achilles Tendons revealed a pronounced increase in wave speed as a function of frequency, which highlights the importance of Tendon viscoelasticity. Additionally, the viscoelastic properties of the Achilles Tendon were larger than those reported for other tissues. Measurements in a tendinopathic Achilles Tendon indicated that it is feasible to quantify local viscoelastic properties. Similarly, measurement in the semitendinosus Tendon revealed substantial differences in viscoelastic properties between the healthy and contralateral Tendons. Consequently, this technique has the potential to evaluate localized changes in Tendon viscoelastic properties caused by injury and during recovery in a clinical setting.
Rene P Van Weere - One of the best experts on this subject based on the ideXlab platform.
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effects of platelet rich plasma on the quality of repair of mechanically induced core lesions in equine superficial digital flexor Tendons a placebo controlled experimental study
Journal of Orthopaedic Research, 2009Co-Authors: G Osch, Hans T M Van Schie, Mark W De Groo, Jennifer A. Cadby, Chris H A Van De Les, Ab Arneveld, Rene P Van WeereAbstract:Tendon injuries are notorious for their slow and functionally inferior healing. Intratendinous application of platelet-rich plasma (PRP) has been reported to stimulate the repair process of Tendon injuries, but there is little conclusive evidence for its effectiveness. A placebo-controlled experimental trial was performed to test the hypothesis that a single intratendinous PRP treatment enhances the quality of Tendon repair, as evidenced by improved biochemical, biomechanical, and histological tissue properties. In six horses, Tendon lesions were created surgically in the Superficial Digital Flexor Tendons (SDFT) of both front limbs, one of which was treated with PRP and the other with saline. After 24 weeks, the Tendons were harvested for biochemical, biomechanical, and histological evaluations. Collagen, glycosaminoglycan, and DNA content (cellularity) was higher in PRP-treated Tendons (p = 0.039, 0.038, and 0.034, respectively). The repair tissue in the PRP group showed a higher strength at failure (p = 0.021) and Elastic Modulus (p = 0.019). Histologically, PRP-treated Tendons featured better organization of the collagen network (p = 0.031) and signs of increased metabolic activity (p = 0.031). It was concluded that PRP increases metabolic activity and seems to advance maturation of repair tissue over nontreated experimentally induced Tendon lesions, which suggests that PRP might be beneficial in the treatment of clinical Tendon injuries. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:211–217, 2010
