Numerical and Experimental Analysis of Articular Chondrocyte Deformation: Calibration of a Multiscale Finite Element Model

Mechanical loading of chondrocytes in isolation [1] and of articular cartilage in culture [2] has been reported to be a potent regulator of chondrocyte metabolism. Experimental studies have related tissue-level and cell-level strains in mechanically loaded cartilage explants [3], but cannot be readily extended to address more physiologic loading cases. Numerical models, which might address this need, have primarily been axisymmetric [4, 5] or two-dimensional [6] and have idealized chondrocyte geometry. Given the complexity of the mechanism of the load transfer between the tissue and cell, however, there remains a lack of information regarding the in vivo level of cell stresses and strains. Thus, the purpose of this study was to develop a multiscale experimental/numerical approach to calibrate a three-dimensional finite element (FE) model of a chondrocyte based on experimentally derived chondrocyte morphology and deformation data. The method was than applied to determine the modulus of a chondrocyte located in the superficial zone.