The human meniscus behaves as a functionally graded fractional porous medium under confined compression conditions

In this study, we observe that the poromechanical parameters in human meniscus vary spatially throughout the tissue. The response is anisotropic and the porosity is functionally graded. To draw these conclusions, we measured the anisotropic permeability and the “aggregate modulus” of the tissue, i.e., the stiffness of the material at equilibrium, after the interstitial fluid has ceased flowing. We estimated those parameters within the central portion of the meniscus in three directions (i.e., vertical, radial and circumferential) by fitting an enhanced model on stress relation confined compression tests. We noticed that a classical biphasic model was not sufficient to reproduce the observed experimental behaviour. We propose a poroelastic model based on the assumption that the fluid flow inside the human meniscus is described by a fractional porous medium equation analogous to Darcy’s law, which involves fractional operators. The fluid flux is then time-dependent for a constant applied pressure gradient (in contrast with the classical Darcy’s law, which describes a time independent fluid flux relation). We show that a fractional poroelastic model is well-suited to describe the flow within the meniscus and to identify the associated parameters (i.e., the order of the time derivative and the permeability). The results indicate that mean values of λβ,β in the central body are λβ=5.5443×10−10m4Ns1−β, β=0.0434, while, in the posterior and anterior regions, are λβ=2.851×10−10m4Ns1−β, β=0.0326 and λβ=1.2636×10−10m4Ns1−β, β=0.0232, respectively. Furthermore, numerical simulations show that the fluid flux diffusion is facilitated in the central part of the meniscus and hindered in the posterior and anterior regions

3D gelatin-chitosan hybrid hydrogels combined with human platelet lysate highly support human mesenchymal stem cell proliferation and osteogenic differentiation

Bone marrow and adipose tissue human mesenchymal stem cells were seeded in highly performing 3D gelatin–chitosan hybrid hydrogels of varying chitosan content in the presence of human platelet lysate and evaluated for their proliferation and osteogenic differentiation. Both bone marrow and adipose tissue human mesenchymal stem cells in gelatin–chitosan hybrid hydrogel 1 (chitosan content 8.1%) or gelatin–chitosan hybrid hydrogel 2 (chitosan 14.9%) showed high levels of viability (80%–90%), and their proliferation and osteogenic differentiation was significantly higher with human platelet lysate compared to fetal bovine serum, particularly in gelatin–chitosan hybrid hydrogel 1. Mineralization was detected early, after 21 days of culture, when human platelet lysate was used in the presence of osteogenic stimuli. Proteomic characterization of human platelet lysate highlighted 59 proteins mainly involved in functions related to cell adhesion, cellular repairing mechanisms, and regulation of cell differentiation. In conclusion, the combination of our gelatin–chitosan hybrid hydrogels with hPL represents a promising strategy for bone regenerative medicine using human mesenchymal stem cells

Reliability and validity of hand-held dynamometer and hand-held sphygmomanometer for testing shoulder isometric external and internal rotator muscles strength

Background: Shoulder strength evaluation is a recommended procedure in musculoskeletal rehabilitation. Aim: To examine hand-held sphygmomanometer (HHS) and hand-held dynamometer (HHD) intra- and inter-rater reliability during isometric shoulder external and internal rotation strength testing in prone rotation position in asymptomatic participants, and to compare these two testing modalities. Design: Reliability study. Methods: A total of 20 asymptomatic participants (27.7 ± 7.4 years; 77.1 ± 10.1 kg) attended a strength assessment consisting of HHS and HHD tests. Reliability was assessed using the intra-class correlation coefficient (ICC) with 95% confidence intervals (CI), coefficient of variation (CV) with 95%CI, and standard error of measurement (SEM). Pearson correlation and linear regression analysis were used to compare HHS and HHD testing modalities. Results: “Good” to “excellent” intra (ICC range = 0.896 to 0.979) and inter-rater reliability scores (ICC range = 0.850 to 0.978) were displayed during both HHS and HHD tests during internal and external rotation strength assessments. Linear relationships between HHS and HHD measures were found, with coefficients of determination (R 2) ranging between 0.60 and 0.79. Conclusion: HHS and HHD resulted to be reliable strength assessment modalities for clinical practice. These assessment modes can be equally valid in assessing intra and inter-limb asymmetries in isometric shoulder rotation strength. The affordability and availability of HHS in ordinary clinical settings can facilitate its implementation in musculoskeletal practice

The human meniscus behaves as a functionally graded fractional porous medium under confined compression conditions

In this study, we observe that the poromechanical parameters in human meniscus vary spatially throughout the tissue. The response is anisotropic and the porosity is functionally graded. To draw these conclusions, we measured the anisotropic permeability and the “aggregate modulus” of the tissue, i.e., the stiffness of the material at equilibrium, after the interstitial fluid has ceased flowing. We estimated those parameters within the central portion of the meniscus in three directions (i.e., vertical, radial and circumferential) by fitting an enhanced model on stress relation confined compression tests. We noticed that a classical biphasic model was not sufficient to reproduce the observed experimental behaviour. We propose a poroelastic model based on the assumption that the fluid flow inside the human meniscus is described by a fractional porous medium equation analogous to Darcy’s law, which involves fractional operators. The fluid flux is then time-dependent for a constant applied pressure gradient (in contrast with the classical Darcy’s law, which describes a time independent fluid flux relation). We show that a fractional poroelastic model is well-suited to describe the flow within the meniscus and to identify the associated parameters (i.e., the order of the time derivative and the permeability). The results indicate that mean values of λβ, β in the central body are λβ = 5.5443 × 10−10 m4 Ns1−β , β = 0.0434, while, in the posterior and anterior regions, are λβ = 2.851 × 10−10 m4 Ns 1−β , β = 0.0326 and λβ = 1.2636 × 10−10 m4 Ns 1−β , β = 0.0232, respectively. Furthermore, numerical simulations show that the fluid flux diffusion is facilitated in the central part of the meniscus and hindered in the posterior and anterior regions

Erratum to: Kinematics of ACL and anterolateral ligament. Part II: anterolateral and anterior cruciate ligament reconstruction

No abstract availabl