The Use of Ultrasound Elastography to Assess Regional Variations in Tendon Strain

Muscle-tendon loading patterns are complex, with computational models suggesting that both muscle and tendinous tissues undergo highly nonuniform deformation patterns [1]. Hence, musculoskeletal tissue injuries may alter both the morphology and mechanical interactions of muscle and tendon, potentially contributing to secondary pathologies. For example, the presence of residual scar tissue following acute strain injury likely alters force transmission across the muscle-tendon junction and contributes to re-injury risk [2]. While visual ultrasonic methods for assessing tendon strain have provided insight into overall tissue mechanics [3], no prior technique has demonstrated the ability to measure strain distributions in vivo. The purpose of the current study was to evaluate the potential use of ultrasound elastography as a tool for measuring in vivo tendon strain patterns. We achieved this purpose by first developing and assessing an elastography-based approach in an ex vivo experimental setup, and then repeating the analysis on pilot ultrasonic data collected in vivo.