Development of a continuum damage model to predict accumulation of sub-failure damage in tendons.

Many painful and physically debilitating conditions involve sub-failure mechanical damage to seemingly intact connective tissues such as tendons and ligaments. We found that the amount of denatured collagen in rat tail tendon (RTT) fascicles increased over experiments of cyclic loading to a constant load level (creep cyclic fatigue) with fluorescently tagged collagen hybridizing peptides (CHPs) that bind to denatured collagen. To better understand tendon sub-failure damage progression, computational modeling of tendon materials via finite element analysis in FEBio has been conducted.

Characterization and finite element validation of transchondral strain in the human hip during static and dynamic loading.

Distribution of strain through the thickness of articular cartilage, or transchondral strain, is highly dependent on the geometry of the joint involved. Excessive transchondral strain can damage the solid matrix and ultimately lead to osteoarthritis. Currently, high-resolution transchondral strain distribution is unknown in the human hip.

Collagen denaturation is initiated upon tissue yield in both positional and energy-storing tendons.

Tendons are collagenous soft tissues that transmit loads between muscles and bones. Depending on their anatomical function, tendons are classified as positional or energy-storing with differing biomechanical and biochemical properties. We recently demonstrated that during monotonic stretch of positional tendons, permanent denatured collagen begins accumulating upon departing the linear region of the stress-strain curve.