Selecting a cartilage constitutive model for finite element analysis of cartilage impact injuries

Articular cartilage is a musculoskeletal soft tissue with a complex, heterogeneous structure that effectively distributes loads to the underlying bone. Understanding relationships between the cartilage mechanical environment and biological activity is crucial for studying cartilage disease progression. Finite element (FE) models are often used to evaluate cartilage mechanics, with the choice of constitutive model being a key factor in model accuracy. This study systematically explores the effects of including fluid representation and fiber-reinforcement in cartilage constitutive models on the FE-computed mechanical behavior of osteochondral explants during exaggerated and physiological impact injuries.