Tendinopathy is a localized tendon injury characterized by loss of normal collagen architecture, increased glycosaminoglycans, hypercellularity, neovascularization, and nerve ingrowth. Overuse (excessive loading) is considered the major causation factor. The Achilles tendon is the strongest tendon in the body but still often injured. In the adult population the incidence rate for Achilles tendinopathy is 2.5 per 1000. Mid-portion tendinopathy is the most common pathological condition in the Achilles tendon and represents between 55% and 65% of the Achilles tendon overuse injuries. The preferred treatment for tendinopathy is therapeutic exercise, which is believed to promote remodeling of the collagenous structure of the tendon. Tendon healing is highly affected by exercise dosage. The two extremes in exercise dosage (immobilization and overuse) have shown to be detrimental for tendon healing. This suggests there is an optimum exercise dosage to maximize function and tendon properties. However, quantifying the effect of treatment (i.e., exercise) is difficult due to the lack non-invasive cost-effective methods to quantify tendon composition, structure and remodeling. Currently, treatments are evaluated using clinical, functional and patient-reported outcomes which evaluate the range of motion of the foot, strength of the lower leg, and symptoms. However, a limitation of these outcomes is the lack of evaluation of tendon structure and mechanical properties. To overcome this limitation, we propose non- invasive measurements of viscoelastic properties, via ultrasound elastography, as an equivalent measurement of changes in composition, structure, and ultimately function of the tendon. We recently developed an ultrasound technique, named Continuous Shear Wave Elastography (cSWE), to measure local viscoelastic properties of tendons. This novel technique is safe, non-invasive, inexpensive, and offer two main advantages over commercially available methods: 1) the parameters can be tune to measure tissue with high stiffness such as the Achilles tendon, 2) the technique can be used to measure spatial variations (i.e. a map) of tendon viscoelastic properties. Therefore, this technique is suitable to evaluate localized lesions caused by tendinopathy, tears or ruptures. The objectives of the study are to quantify the effect of mid-portion tendinopathy on the viscoelastic properties of the Achilles tendon at the moment of diagnosis and during treatment and to explore possible correlations between viscoelastic properties and clinical/functional outcomes. This study will help establishing cSWE as a clinical technique that can potentially play an important role in optimizing a therapeutic exercise program and/or other treatments for tendinopathy to achieve faster return of function, preventing long-term deficits and re-injury, and minimizing the burden and cost to the health care system.

Public Health Relevance

There is a lack of non-invasive cost-effective methods to quantify the effect of tendon injuries on their structural and mechanical properties. This study will evaluate the feasibility of using our novel ultrasound elastography technique to evaluate changes of tendon structural and mechanical properties due to tendinopathy. This technique can potentially play an important role in optimizing a therapeutic exercise program and/or other treatments for tendinopathy to achieve faster return of function, preventing long-term deficits and re-injury, and minimizing the burden and cost to the health care system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AR067390-01
Application #
8808800
Study Section
Skeletal Biology Structure and Regeneration Study Section (SBSR)
Program Officer
Panagis, James S
Project Start
2015-02-13
Project End
2017-01-31
Budget Start
2015-02-13
Budget End
2016-01-31
Support Year
1
Fiscal Year
2015
Total Cost
$166,116
Indirect Cost
$46,554
Name
University of Delaware
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
059007500
City
Newark
State
DE
Country
United States
Zip Code
19716
Zellers, Jennifer A; Carmont, Michael R; Silbernagel, Karin Grävare (2017) Achilles Tendon Resting Angle Relates to Tendon Length and Function. Foot Ankle Int :1071100717742372
Zellers, Jennifer A; Carmont, Michael R; Grävare Silbernagel, Karin (2016) Return to play post-Achilles tendon rupture: a systematic review and meta-analysis of rate and measures of return to play. Br J Sports Med :
Zellers, Jennifer A; Cortes, Daniel H; Silbernagel, Karin Grävare (2016) FROM ACUTE ACHILLES TENDON RUPTURE TO RETURN TO PLAY - A CASE REPORT EVALUATING RECOVERY OF TENDON STRUCTURE, MECHANICAL PROPERTIES, CLINICAL AND FUNCTIONAL OUTCOMES. Int J Sports Phys Ther 11:1150-1159
Suydam, Stephen M; Soulas, Elizabeth M; Elliott, Dawn M et al. (2015) Viscoelastic properties of healthy achilles tendon are independent of isometric plantar flexion strength and cross-sectional area. J Orthop Res 33:926-31
Cortes, Daniel H; Suydam, Stephen M; Silbernagel, Karin Grävare et al. (2015) Continuous Shear Wave Elastography: A New Method to Measure Viscoelastic Properties of Tendons in Vivo. Ultrasound Med Biol 41:1518-29