AGES effect on the biomechanics of the knee tendon

Aging and diabetes, and some other diseases that are associated with a remarkable growth of non-enzymatical cross-links (advanced glycation end-products AGEs) were considered important contributors to increasing patellar tendon injury susceptibility and low healing capacity. While a clear coupling between this collagen structural alteration (AGEs) and tendon mechanics still needs further investigation. In this study, a multiscale fibril-reinforced hyper-elastoplastic model was employed to elucidate the effect of the AGEs density alteration on the aggregate mechanics of the tendons' behavior. Our results showed a clear decrease in tendon stiffness at the pre-yielding stage associated with a higher stress concentration in the normal case. In contrast, a higher tendon stiffness and more brutal reaction were computed after the normal post-yield stage with unbalanced growth of the AGEs. This prediction has potentially important implications for understanding the tissue damage mechanism associated with collagen microstructural alteration.