Damage Modeling of the Human Meniscus: Validating Finite Element Models with Digital Image Correlation

Meniscus tears are one of the most common orthopedic injuries, with more than a half-million surgeries performed annually in the U.S. The healing capacity of meniscus becomes diminished with age, and surgical interventions to remove damaged tissue increase the likelihood of osteoarthritis. With the lack of effective treatment options to fully restore meniscus function, preventing meniscus tear injuries is of utmost importance to combat osteoarthritis. The design of preventive therapies can be improved by computational tools like finite element analysis (FEA) to predict tears, similar to what has been done to inform treatments of aortic aneurysms. One way that FEA can be effectively used to predict material failure, is by using Continuum Damage Mechanics (CDM) to model material weakening due to the onset of damage. However, the validation of an appropriate constitutive framework requires model comparisons to experimental data.Our previous experimental work in human meniscus tracked the progression of surface strains in the tear region using high-speed video and digital image correlation (DIC), enabling the onset and progression of material damage to be measured at specific points of interest on the stress-strain curve. This localized data can be used to validate that the appropriate failure behavior is being captured by a predictive CDM model, increasing the probability that the model is truly representing physiological behavior.

 

O bjective. The objectives of this work are to (1) fit a CDM model to the anisotropic tensile stress-stretch behavior of human meniscus and (2) validate that the model predicts the localized planar strains in the tear region as measured by DIC. Our hypothesis is that a CDM model using the maximum normal Lagrange strain failure criteria will reproduce the magnitude of the normal strains in the tear region at yield and ultimate strength, while closely matching the stress-stretch profile during quasi-static tensile tests.