An acoustic wearable for assessment of tendon health and loading condition

Current methods for assessing tendon health, such as clinical examinations, imaging techniques, and implanted pressure sensors, are often subjective, expensive, and primarily effective for detecting significant damage. Advanced wearables offer a precise, cost-effective, and non-invasive alternative. In this study, we propose an acoustic-based wearable device designed to estimate tendon load and predict damage severity in both deep and superficial tendons. The wearable comprises an array of acoustic transducers arranged in a cuff around the targeted body area. One transducer generates acoustic waves that propagate through various tissues, where their behavior is influenced by the mechanical and geometric properties of each tissue. By analyzing these interactions, we measure tendon strains and detect defects. The load estimation capability of the proposed wearable was tested using 18 porcine flexor digitorum tendons from cadaveric pig legs, while its diagnostic capability was evaluated by inducing three types of defects in the tendons. Results indicate that the acoustic wearable demonstrates robust performance in estimating the force applied to tendons and effectively compares tendon health conditions, accurately predicting the type of damage.