Open AccessA novel application of strain sonoelastography can detect changes in Achilles tendon elasticity during isometric contractions of increasing intensity
Author(s) -
Schneebeli Alessandro,
Del Grande Filippo,
Falla Deborah,
Cescon Corrado,
Clijsen Ron,
Barbero Marco
Publication year - 2019
Publication title -
journal of foot and ankle research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.763
H-Index - 39
ISSN - 1757-1146
DOI - 10.1186/s13047-019-0342-1
Subject(s) - isometric exercise , medicine , achilles tendon , elasticity (physics) , tendon , strain (injury) , orthopedic surgery , intensity (physics) , biomedical engineering , physical medicine and rehabilitation , surgery , radiology , optics , composite material , materials science , physics
Background Mechanical and morphological properties of the Achilles tendon are altered in disease and in response to changes in mechanical loading. In the last few years different ultrasound based technologies have been used to detect tendon mechanical properties changes mainly in resting condition. Therefore the aim of this study was to evaluate if strain sonoelastography can identify changes in Achilles tendon elasticity during isometric contractions of increasing intensity. Methods This cross‐sectional study enrolled 37 healthy volunteers (19 women) with mean (±SD) age of 27.1 (±7.0) years between January and June 2017. Strain sonoelastography images of the Achilles tendon were acquired during an isometric ramp force (0 kg, 0.5 kg, 1 kg, 2 kg, 5 kg and, 10 kg). An external reference material was used to provide a comparison between the examined tissue and a material of constant elasticity. Friedman test with post hoc pairwise comparison were used to determine the correlation between the difference contraction levels. Results The median and interquartile range (IQR) values for the strain ratio were 1.61 (1.5–2.9) in a relaxed state and 1.30 (1.07–2.02), 1.00 (0.76–1.66), 0.81 (0.70–1.19), 0.47 (0.39–0.73) and 0.33 (0.28–0.40) for 0.5 kg, 1 kg, 2 kg, 5 kg and 10 kg, respectively revealing increased tendon hardness with increasing contraction intensities. Friedman test revealed significant differences ( p < 0.05) in the strain ratio between all contractions except between 0.5 kg – 1 kg ( p = 0.41); 1 kg – 2 kg ( p = 0.12) and 5 kg – 10 kg (p = 0.12). Conclusion Strain sonoelastography can detect changes in Achilles tendon elasticity between different contraction intensities. The results provide an original force‐elasticity curve for the Achilles tendon in a healthy, asymptomatic population. Trial registration The study was approved by the Ethics Committee of Canton Ticino.