Prediction of Articular Cartilage Remodeling During Dynamic Compression with a Finite Element Model

First, an in vitro growth experiment was performed to test the hypothesis that applying dynamic unconfined compression during culture produces het- erogeneous remodeling in newborn bovine articular cartilage explants. Het- erogeneous measures of cartilage microstructure were obtained by biochemical assays and quantified polarized light microscopy. Significant differences were measured between the GAG content in the inner and outer portions of the sam- ples stimulated with dynamic unconfined compression. The COL fiber network was found to be more highly aligned in the inner portion of the sample than in the peripheral region. Next, a poroelastic finite element model with a remodeling subroutine was developed to test the hypothesis that the magnitude of relative interstitial fluid velocity and maximum principle strain stimulate GAG and COL fiber network remodeling, respectively, in articular cartilage during culture with dynamic unconfined compression. The GAG remodeling law was successful in predicting the heterogeneous changes in GAG content. The collagen remodeling law was not successful in predicting the changes in the COL network microstructural orientation, suggesting another mechanical cue is responsible for stimulating the remodeling of the COL fiber network