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Updated: Mar 19, 2026
Author Spotlight: Exploring the Complexities of Achilles Tendon Injuries — Research and Future Directions
Published on: October 27, 2023
Extended field of view ultrasound imaging to evaluate Achilles tendon length and thickness: a reliability and
Karin Gravare Silbernagel1, Kristen Shelley2, Stephen Powell2
1Department of Physical Therapy, University of Delaware, Newark, USA.
Background:
Achilles tendon structural changes are common after injury and correlate with recovery of function. Having simple, inexpensive, yet valid and reliable measures of Achilles tendon structure are useful both in research and clinical. The purpose of this study was to perform reliability and validity measures of extended field of view (EFOV) ultrasound (US) imaging of the Achilles tendon.
Methods:
eight cadavers (16 tendons) were used for the validation study to compare Achilles tendon length measurements from US images with actual measured length from dissected tendons. Nine healthy subjects (18 tendons) were included in the test-retest evaluation.
Results:
the correlation between the US images and cadaveric measurements was excellent (ICC=0.895) for the length between calcaneus and the gastrocnemius and good (ICC=0.744) for the length between the calcaneus and the soleus. The between-limb reliability was excellent (ICC 0.886-0.940) for the tendon length measurements with standard error of measurements (SEM) of 0.64 cm for calcaneus to soleus and 0.67 cm for calcaneus to gastrocnemius. Between-day test-retest reliability was also excellent (ICC=0.898-0.944).
Conclusion:
this study supports the use of EFOV US imaging as a reliable and valid method to determine Achilles tendon length and thickness, and using the uninjured limb for comparison.
