Evaluation of tissue displacement and regional strain in the Achilles tendon using quantitative high-frequency ultrasound

PLoS One. 2017 Jul 20;12(7):e0181364. doi: 10.1371/journal.pone.0181364. eCollection 2017.

Abstract

The Achilles tendon has a unique structure-function relationship thanks to its innate hierarchical architecture in combination with the rotational anatomy of the sub-tendons from the triceps surae muscles. Previous research has provided valuable insight in global Achilles tendon mechanics, but limitations with the technique used remain. Furthermore, given the global approach evaluating muscle-tendon junction to insertion, regional differences in tendon mechanical properties might be overlooked. However, recent advancements in the field of ultrasound imaging in combination with speckle tracking have made an intratendinous evaluation possible. This study uses high-frequency ultrasound to allow for quantification of regional tendon deformation. Also, an interactive application was developed to improve clinical applicability. A dynamic ultrasound of both Achilles tendons of ten asymptomatic subjects was taken. The displacement and regional strain in the superficial, middle and deep layer were evaluated during passive elongation and isometric contraction. Building on previous research, results showed that the Achilles tendon displaces non-uniformly with a higher displacement found in the deep layer of the tendon. Adding to this, a non-uniform regional strain behavior was found in the Achilles tendon during passive elongation, with the highest strain in the superficial layer. Further exploration of tendon mechanics will improve the knowledge on etiology of tendinopathy and provide options to optimize existing therapeutic loading programs.

MeSH terms

  • Achilles Tendon / diagnostic imaging*
  • Achilles Tendon / physiology*
  • Adult
  • Female
  • Humans
  • Isometric Contraction / physiology*
  • Male
  • Movement / physiology
  • Reproducibility of Results
  • Signal Processing, Computer-Assisted
  • Ultrasonography* / methods

Grants and funding

The author(s) received no specific funding for this work.