Strain-induced damage reduces echo intensity changes in tendon during loading - PubMed (original) (raw)

Strain-induced damage reduces echo intensity changes in tendon during loading

Sarah Duenwald-Kuehl et al. J Biomech. 2012.

Abstract

Tendon functionality is related to its mechanical properties. Tendon damage leads to a reduction in mechanical strength and altered biomechanical behavior, and therefore leads to compromised ability to carry out normal functions such as joint movement and stabilization. Damage can also accumulate in the tissue and lead to failure. A noninvasive method with which to measure such damage potentially could quantify structural compromise from tendon injury and track improvement over time. In this study, tendon mechanics are measured before and after damage is induced by "overstretch" (strain exceeding the elastic limit of the tissue) using a traditional mechanical test system while ultrasonic echo intensity (average gray scale brightness in a B-mode image) is recorded using clinical ultrasound. The diffuse damage caused by overstretch lowered the stress at a given strain in the tissue and decreased viscoelastic response. Overstretch also lowered echo intensity changes during stress relaxation and cyclic testing. As the input strain during overstretch increased, stress levels and echo intensity changes decreased. Also, viscoelastic parameters and time-dependent echo intensity changes were reduced.

Copyright © 2012 Elsevier Ltd. All rights reserved.

PubMed Disclaimer

Figures

Figure 1

Figure 1

Experimental setup to acquire mechanical and ultrasonic data simultaneously. All testing was conducted in the PBS-filled bath which acted to keep the tendon hydrated and transmit ultrasound waves to and from the tendon surface.

Figure 2

Figure 2

Stress vs. time before and after diffuse damage induced by overstretch during a) cyclic testing (cycles 8-10) and b) stress relaxation testing (first 5 seconds) from one representative specimen. Note that the overall stress is decreased following damage, as is the stress decay during the first 5 seconds of relaxation. The relaxation curve shows 50% of the relaxation points during the first 5 seconds of relaxation. The relaxation curve shows 50% of the relaxation points for clarification.

Figure 3

Figure 3

Echo intensity change before and after diffuse damage induced by overstretch during a) cyclic testing (cycles 8-10) and b) stress relaxation testing (first 5 seconds) from one representative specimen. Note that the overall echo intensity change is decreased following damage, as is the increase in intensity during 5 seconds of relaxation (see Figure 2 for related force vs. time data). The relaxation curve shows 50% of the relaxation points for clarification.

Figure 4

Figure 4

Post- to pre-damage ratios of mechanical parameters from a) cyclic testing and b) stress relaxation testing for specimens. As strain during overstretch increases, post-damage parameter values decrease. Error bars indicate one standard deviation.

Figure 5

Figure 5

Post- to pre-damage ratios of ultrasound parameters from a) cyclic testing and b) stress relaxation testing for specimens. As strain during overstretch increases, post-damage parameter values decrease. Error bars indicate one standard deviation.

Similar articles

Cited by

References

    1. Arda K, Ciledag N, Aktas E, Arıbas BK, Köse K. Quantitative Assessment of Normal Soft-Tissue Elasticity Using Shear-Wave Ultrasound Elastography. American Journal of Roentgenology. 2011;197(3):532–536. - PubMed
    1. Brown TD, Fu FH, Hanley EN., Jr. Comparative Assessment of the Early Mechanical Integrity of Repaired Tendon Achillis Ruptures in the Rabbit. The Journal of Trauma. 1981;21(11):951–957. - PubMed
    1. Catheline S, Gennisson J-L, Fink M. Measurement of Elastic Nonlinearity of Soft Solid with Transient Elastography. The Journal of the Acoustical Society of America. 2003;114:3087–3091. - PubMed
    1. Crevier-Denoix N, Ravary-Plumioën B, Evrard D, Pourcelot P. Reproducibility of a Non-invasive Ultrasonic Technique of Tendon Force Measurement, Determined in Vitro in Equine Superficial Digital Flexor Tendons. Journal of Biomechanics. 2009;42(13):2210–2213. - PubMed
    1. D'hooge J, Heimdal A, Jamal F, Kukulski T, Bijnens B, Rademakers F, Hatle L, Suetens P, Sutherland GR. Regional Strain and Strain Rate Measurements by Cardiac Ultrasound: Principles, Implementation and Limitations. European Journal of Echocardiography. 2000;1(3):154–170. - PubMed

Publication types

MeSH terms

LinkOut - more resources