###### Abstract  
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 [PERSON]'s law, which involves fractional operators. The fluid flux is then time-dependent for a constant applied pressure gradient (in contrast with the classical [PERSON]'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 \(\lambda_{\beta},\beta\) in the central body are \(\lambda_{\beta}=5.5443\times 10^{-10}\frac{\text{m}^{4}}{\text{Ns}^{-1} \text{-}\text{-}\text{-}\text{-}\text{-}\text{-}\text{-}\text{-}\text{-}\text{ }\text{-}\text{-}\text{-}\text{-}\text{-}\text{-}\text{-}  
the joint), joint stability and lubrication [1; 2]. Degenerative processes of the meniscus, either from injuries or ageing, affect approximately 35% of the population [3]. When required, the most common surgical procedure is currently total/partial meniscectomy (i.e., removal of the damaged tissue). It has been noticed that, although the knee joint can still function with the total/partial absence of the meniscus, the loss of the meniscus leads to an increase in the contact stresses on the tibial/femoral cartilage proportional to the amount of meniscal tissue removed [4]. The increase in contact stresses on the cartilage is one of the main factors of Osteoarthritis (OA). Therefore, partial/total meniscal replacements are expected to help avoid articular cartilage degeneration. Currently, the clinical outcomes of these implants are not ideal [5] due to the fact that they do not mimic the structure-property relationships of the tissue as these are still not well understood [6]. Among many biologic tissues, the meniscal tissue is composed of porous solid matrices--mainly collagen--with fluid filling the pores [7; 8; 9; 10]. The overall mechanical behaviour of this type of tissues depends not only on the solid matrix deformation, but also on the movement of the fluid in and out of the collagen channels [7; 8] during the deformation. Meniscal tissue exhibit a non-uniform and anisotropic porosity, which is related to the graded material properties. Such graded material properties are fundamental for the correct functioning of this tissue [8]. The investigation of the material properties, coupled with the quantification of architectural parameters, such as the porosity and channel interconnectivity, will enable the design of artificial cellular structure, which can resemble the native behaviour of the tissue (see, for instance, [11]). More in depth, advanced microscopy investigations highlighted that collagen bundles form the wall of channels, which can be observed both at the macroscale and at the microscale [7; 10]. Fluid is able to flow inside these channels in response to physiological loading.