The authors would like to thank past and current members of the Delaware Tendon Research Group who have assisted in data collection using this protocol. Research reported in this publication was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Numbers R01AR072034, R01AR078898, F31AR081663, R21AR067390, and by Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health under the award number T32HD007490. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Research reported in this publication was also supported by grants provided by the Swedish Research Council for Sport Science, the Stockholm County Council (ALF project), and the Swedish Research Council. This work was&#160;also supported in part by a Promotion of Doctoral Studies Scholarship from the Foundation for&#160;Physical Therapy Research and by the Rheumatology Research Foundation Medical and Graduate Student Preceptorship.

The following protocol follows the guidelines set forth by and has been approved by the University Institutional Review Board to ensure safe and ethical human subject research. All subjects provided informed consent for participation in the research studies and dissemination of data. The full protocol takes approximately 20 minutes to perform by a trained sonographer. However, individual measurements may be taken per assessment need.
1. Marking of the skin
<ol>
	<li>Ask the participant to be...

Ultrasound Evaluation of Achilles Tendon Morphology

<ol>
	<li>Millar, N. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tendinopathy.">Tendinopathy.</a> Nat Rev Dis Primers. 7 (1), 1 (2021).</li><li>Silbernagel, K. G., Hanlon, S., Sprague, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+clinical+concepts:+Conservative+management+of+Achilles+tendinopathy.">Current clinical concepts: Conservative management of Achilles tendinopathy.</a> J Athl Train. 55 (5), 438-447 (2020).</li><li>Chimenti, R. L., Cychosz, C. C., Hall, M. M., Phisitkul, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+concepts+review+update:+insertional+Achilles+tendinopathy.">Current concepts review update: insertional Achilles tendinopathy.</a> Foot Ankle Int. 38 (10), 1160-1169 (2017).</li><li>Zellers, J. A., Pohlig, R. T., Cortes, D. H., Gr&#228;vare Silbernagel, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achilles+tendon+cross-sectional+area+at+12+weeks+post-rupture+relates+to+1-year+heel-rise+height.">Achilles tendon cross-sectional area at 12 weeks post-rupture relates to 1-year heel-rise height.</a> Knee Surg Sports Traumatol Arthrosc. 28 (1), 245-252 (2020).</li><li>Aufwerber, S., Edman, G., Gr&#228;vare Silbernagel, K., Ackermann, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+tendon+elongation+and+muscle+atrophy+over+time+after+Achilles+tendon+rupture+repair:+a+prospective+cohort+study+on+the+effects+of+early+functional+mobilization.">Changes in tendon elongation and muscle atrophy over time after Achilles tendon rupture repair: a prospective cohort study on the effects of early functional mobilization.</a> Am J Sports Med. 48 (13), 3296-3305 (2020).</li><li>Heikkinen, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tendon+length,+calf+muscle+atrophy,+and+strength+deficit+after+acute+Achilles+tendon+rupture:+Long-term+follow-up+of+patients+in+a+previous+study.">Tendon length, calf muscle atrophy, and strength deficit after acute Achilles tendon rupture: Long-term follow-up of patients in a previous study.</a> J Bone Joint Surg Am. 99 (18), 1509-1515 (2017).</li><li>Corrigan, P., Cortes, D. H., Pohlig, R. T., Gr&#228;vare Silbernagel, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tendon+morphology+and+mechanical+properties+are+associated+with+the+recovery+of+symptoms+and+function+in+patients+with+Achilles+tendinopathy.">Tendon morphology and mechanical properties are associated with the recovery of symptoms and function in patients with Achilles tendinopathy.</a> Orthop J Sports Med. 8 (4), 2325967120917271 (2020).</li><li>De Jonge, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+neovascularization+and+clinical+severity+in+Achilles+tendinopathy+in+556+paired+measurements.">Relationship between neovascularization and clinical severity in Achilles tendinopathy in 556 paired measurements.</a> Scand J Med Sci Sports. 24 (5), 773-778 (2014).</li><li>De Jonge, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+tendon+structure+returns+to+asymptomatic+values+in+nonoperatively+treated+Achilles+tendinopathy+but+is+not+associated+with+symptoms:+A+prospective+study.">The tendon structure returns to asymptomatic values in nonoperatively treated Achilles tendinopathy but is not associated with symptoms: A prospective study.</a> Am J Sports Med. 43 (12), 2950-2958 (2015).</li><li>Silbernagel, K. G., Shelley, K., Powell, S., Varrecchia, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extended+field+of+view+ultrasound+imaging+to+evaluate+Achilles+tendon+length+and+thickness:+A+reliability+and+validity+study.">Extended field of view ultrasound imaging to evaluate Achilles tendon length and thickness: A reliability and validity study.</a> Muscles Ligaments Tendons J. 6 (1), 104-110 (2016).</li><li>Albano, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+resonance+and+ultrasound+in+Achilles+tendinopathy:+predictive+role+and+response+assessment+to+platelet-rich+plasma+and+adipose-derived+stromal+vascular+fraction+injection.">Magnetic resonance and ultrasound in Achilles tendinopathy: predictive role and response assessment to platelet-rich plasma and adipose-derived stromal vascular fraction injection.</a> Eur J Radiol. 95, 130-135 (2017).</li><li>Alghamdi, N. H., Killian, M., Aitha, B., Pohlig, R. T., Silbernagel, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantifying+the+dimensions+of+Achilles+tendon+insertional+area+using+ultrasound+imaging+a+validity+and+reliability+study.">Quantifying the dimensions of Achilles tendon insertional area using ultrasound imaging a validity and reliability study.</a> Muscles Ligaments Tendons J. 9 (4), 544-551 (2019).</li><li>Park, E. S., Sim, E., Rha, D. W., Jung, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+gastrocnemius+muscle+volume+using+ultrasonography+in+children+with+spastic+cerebral+palsy.">Estimation of gastrocnemius muscle volume using ultrasonography in children with spastic cerebral palsy.</a> Yonsei Med J. 55 (4), 1115-1122 (2014).</li><li>Risch, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Is+sonographic+assessment+of+intratendinous+blood+flow+in+achilles+tendinopathy+patients+reliable?:+Consistency+of+Doppler+ultrasound+modes+and+intra-+and+inter-observer+reliability.">Is sonographic assessment of intratendinous blood flow in achilles tendinopathy patients reliable?: Consistency of Doppler ultrasound modes and intra- and inter-observer reliability.</a> Ultrasound Int Open. 2 (1), E13-E18 (2016).</li><li>Risch, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reliability+of+evaluating+Achilles+tendon+vascularization+assessed+with+Doppler+ultrasound+advanced+dynamic+flow.">Reliability of evaluating Achilles tendon vascularization assessed with Doppler ultrasound advanced dynamic flow.</a> J Ultrasound Med. 37 (3), 737-744 (2018).</li><li>Forney, M. C., Delzell, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Musculoskeletal+ultrasonography+basics.">Musculoskeletal ultrasonography basics.</a> Cleve Clin J Med. 85 (4), 283-300 (2018).</li><li>Dams, O. C., Reininga, I. H. F., Gielen, J. L., van den Akker-Scheek, I., Zwerver, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+modalities+in+the+diagnosis+and+monitoring+of+Achilles+tendon+ruptures:+A+systematic+review.">Imaging modalities in the diagnosis and monitoring of Achilles tendon ruptures: A systematic review.</a> Injury. 48 (11), 2383-2399 (2017).</li><li>Fredberg, U., Bolvig, L., Andersen, N. T., Stengaard-Pedersen, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonography+in+evaluation+of+Achilles+and+patella+tendon+thickness.">Ultrasonography in evaluation of Achilles and patella tendon thickness.</a> Ultraschall Med. 29 (1), 60-65 (2007).</li><li>Dudley-Javoroski, S., McMullen, T., Borgwardt, M. R., Peranich, L. M., Shields, R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reliability+and+responsiveness+of+musculoskeletal+ultrasound+in+subjects+with+and+without+spinal+cord+injury.">Reliability and responsiveness of musculoskeletal ultrasound in subjects with and without spinal cord injury.</a> Ultrasound Med Biol. 36 (10), 1594-1607 (2010).</li><li>Zellers, J. A., Cortes, D. H., Pohlig, R. T., Silbernagel, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tendon+morphology+and+mechanical+properties+assessed+by+ultrasound+show+change+early+in+recovery+and+potential+prognostic+ability+for+6-month+outcomes.">Tendon morphology and mechanical properties assessed by ultrasound show change early in recovery and potential prognostic ability for 6-month outcomes.</a> Knee Surg Sports Traumatol Arthrosc. 27 (9), 2831-2839 (2019).</li><li>Zellers, J. A., Bley, B. C., Pohlig, R. T., Alghamdi, N. H., Silbernagel, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Frequency+of+pathology+on+diagnostic+ultrasound+and+relationship+to+patient+demographics+in+individuals+with+insertional+Achilles+tendinopathy.">Frequency of pathology on diagnostic ultrasound and relationship to patient demographics in individuals with insertional Achilles tendinopathy.</a> Int J Sports Phys Ther. 14 (5), 761-769 (2019).</li><li>de Jonge, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Incidence+of+midportion+Achilles+tendinopathy+in+the+general+population.">Incidence of midportion Achilles tendinopathy in the general population.</a> Br J Sports Med. 45 (13), 1026-1028 (2011).</li><li>Lemme, N. J., Li, N. Y., DeFroda, S. F., Kleiner, J., Owens, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology+of+Achilles+tendon+ruptures+in+the+United+States:+athletic+and+nonathletic+injuries+from+2012+to+2016.">Epidemiology of Achilles tendon ruptures in the United States: athletic and nonathletic injuries from 2012 to 2016.</a> Orthop J Sports Med. 6 (11), 2325967118808238 (2018).</li><li>Jackson, J. B., Chu, C. H., Williams, K. A., Bornemann, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+ultrasonographic+parameters+of+the+posterior+tibial,+peroneal,+and+Achilles+tendons.">Normal ultrasonographic parameters of the posterior tibial, peroneal, and Achilles tendons.</a> Foot Ankle Spec. 12 (5), 480-485 (2019).</li><li>Schmidt, W. A., Schmidt, H., Schicke, B., Gromnica-Ihle, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+reference+values+for+musculoskeletal+ultrasonography.">Standard reference values for musculoskeletal ultrasonography.</a> Ann Rheum Dis. 63 (8), 988-994 (2004).</li><li>Ackermann, P. W., Hart, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Metabolic Influences on Risk for Tendon Disorders. , (2016).</li><li>Westh, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+habitual+exercise+on+the+structural+and+mechanical+properties+of+human+tendon,+in+vivo,+in+men+and+women.">Effect of habitual exercise on the structural and mechanical properties of human tendon, in vivo, in men and women.</a> Scand J Med Sci Sports. 18 (1), 23-30 (2008).</li><li>Cassel, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence+of+Achilles+and+patellar+tendinopathy+and+their+association+to+intratendinous+changes+in+adolescent+athletes.">Prevalence of Achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes.</a> Scand J Med Sci Sports. 25 (3), e310-e318 (2015).</li><li>Hirschm&#252;ller, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achilles+tendon+power+Doppler+sonography+in+953+long+distance+runners+-+a+cross+sectional+study.">Achilles tendon power Doppler sonography in 953 long distance runners - a cross sectional study.</a> Ultraschall Med. 31 (4), 387-393 (2010).</li><li>Radovanovi&#263;, G., Bohm, S., Arampatzis, A., Legerlotz, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Achilles+tendinopathy+the+symptomatic+tendon+differs+from+the+asymptomatic+tendon+while+exercise+therapy+has+little+effect+on+asymmetries-an+ancillary+analysis+of+data+from+a+controlled+clinical+trial.">In Achilles tendinopathy the symptomatic tendon differs from the asymptomatic tendon while exercise therapy has little effect on asymmetries-an ancillary analysis of data from a controlled clinical trial.</a> J Clin Med. 12 (3), 1102 (2023).</li><li>Corrigan, P., Cortes, D. H., Pontiggia, L., Silbernagel, K. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+degree+of+tendinosis+is+related+to+symptom+severity+and+physical+activity+levels+in+patients+with+midportion+Achilles+tendinopathy.">The degree of tendinosis is related to symptom severity and physical activity levels in patients with midportion Achilles tendinopathy.</a> Int J Sports Phys Ther. 13 (2), 196-207 (2018).</li><li>Enriquez, J. L., Wu, T. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+introduction+to+ultrasound+equipment+and+knobology.">An introduction to ultrasound equipment and knobology.</a> Crit Care Clin. 30 (1), 25-45 (2014).</li><li>Jacobson, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Fundamentals of Musculoskeletal Ultrasound 3rd Edition. , (2018).</li><li>Scanlan, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sonographic+artifacts+and+their+origins.">Sonographic artifacts and their origins.</a> AJR Am J Roentgenol. 156 (6), 1267-1272 (1991).</li><li>Gimber, L. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Artifacts+at+musculoskeletal+US:+resident+and+fellow+education+feature.">Artifacts at musculoskeletal US: resident and fellow education feature.</a> Radiographics. 36 (2), 479-480 (2016).</li></ol>

Critical steps in the protocol to ensure the validity and reliability of the methods include the use of skin markings on participants to guide the ultrasound exam and the required training of individuals performing the measurements used in research studies. Skin markings at specific documented locations assist in the ability to assess variables of interest consistently and accurately at the same locations in the same individual over time. Furthermore, applying skin markings to different individuals in the same systematic...

The Achilles tendon originates at the myotendinous junctions of the gastrocnemius and soleus muscles and inserts on the posterior calcaneus. The Achilles tendon consists primarily of densely packed, organized collagen tissue arranged in a hierarchical fashion to maximize tensile strength1. Despite its ability to withstand heavy forces, the Achilles tendon is susceptible to several types of injuries throughout one&#39;s lifespan. These injuries, such as Achilles tendinopathy and Achilles tendon ruptures, are often accompanied by changes in the structure of the triceps surae and surrounding tissues. In Achilles tendinopathy, patients often exhibit fusiform tendon thickening, tendinosis, collagen disorganization, and neovascularization, a process of proliferation of vascular and neural tissue into the tendon2. Additionally, pathological changes associated with Achilles tendinopathy include paratendinitis, intratendinous, and/or entheseal calcifications, and bursitis2,3. After Achilles tendon ruptures, structural changes are common occurrences, irrespective of treatment, and include Achilles tendon thickening and increased tendon length4,5. Furthermore, muscular changes, such as triceps surae muscular atrophy, are also commonly associated with Achilles tendon injuries5,6.
The ability to assess triceps surae and surrounding tissue structures provides valuable insight into structural integrity, tissue quality, and size, which are known to relate to symptoms, function, and prognosis4,7,8,9. Ultrasound imaging is a reliable and valid assessment tool of these structures, including, but not limited to, Achilles tendon length10, thickness10,11, cross-sectional area (CSA)12, gastrocnemius anatomical CSA13, and neovascularization14,15. Assessment of these measures provides valuable insight into the understanding of healthy triceps surae tissue, as well as quantification of structural alterations to evaluate injury risk, severity, and recovery, as well as understanding healthy tissue qualities16.
Despite the clinical and research utility of ultrasound imaging in assessing triceps surae structure, there are often differences in imaging techniques and measurement parameters among clinical and research studies17,18. As a result, comparisons between studies are difficult. Therefore, the purpose of this methods paper is to describe a valid and reliable protocol for efficiently evaluating triceps surae muscle and tendon structure using musculoskeletal ultrasound imaging. This protocol aims to demonstrate the feasibility of incorporating this tool into research and clinical settings through its entirety or as specific parts in healthy and injured individuals. In addition, representative values for healthy and injured triceps surae are provided.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Aquaflex Stand Off Pad</td>
			<td>Parker Laboratories&#160;</td>
			<td>E8317C</td>
			<td></td>
		</tr>
		<tr>
			<td>Aquasonic ultrasound Gel</td>
			<td>Parker Laboratories&#160;</td>
			<td>E8365AF</td>
			<td></td>
		</tr>
		<tr>
			<td>Linear Array Ultrasound Probe L4-12t-RS</td>
			<td>GE Healthcare</td>
			<td>5495987</td>
			<td></td>
		</tr>
		<tr>
			<td>LOGIC e Ultrasound</td>
			<td>GE Healthcare</td>
			<td>E8349PA</td>
			<td></td>
		</tr>
		<tr>
			<td>Osirix Dicom Viewer</td>
			<td>Pixmeo SARL</td>
			<td></td>
			<td>Software for measurements</td>
		</tr>
	</tbody>
</table>

measurement of healthy and injured triceps surae morphology

Achilles tendon injuries occur throughout the lifespan and can negatively affect quality of life and overall health. Achilles tendinopathy is generally classified as an overuse injury associated with fusiform tendon thickening, neovascularization, and interstitial tendon degeneration. Current literature suggests these structural changes are associated with&#160;symptoms and lower physical activity levels, as well as&#160;symptoms and lower extremity function in the long term. Surgically and non-surgically managed Achilles tendon ruptures result in increased tendon cross-sectional area (CSA) and a lengthened Achilles tendon. Both structural outcomes have clinical implications, as larger CSA positively predicts function, whereas increased tendon lengthening predicts reduced function after Achilles tendon rupture. Given the relationship between structural changes associated with Achilles tendon injuries for both injury severity and injury recovery, it is critical to be able to quantify Achilles tendon structure reliably and accurately. Silbernagel&#39;s group has established a valid and reliable method for efficiently evaluating triceps surae muscle and tendon structure. In this protocol, B-mode musculoskeletal ultrasound imaging is used to measure triceps surae structure, including Achilles tendon thickness and CSA, soleus thickness, and the presence of additional findings (calcifications and bursitis). B-mode extended field-of-view is used to measure Achilles tendon length and gastrocnemius anatomical CSA. Finally, power Doppler is used to identify intratendinous neovascularization. Quantification of triceps surae structure allows for comparison between limbs as well as longitudinal changes in response to exercise and treatment for healthy individuals and those with Achilles tendon injuries. This protocol has been used in many research studies to date and proves valuable in understanding the relationship between tendon structure and injury development, severity, and recovery. As ultrasound devices are becoming more affordable and portable, this protocol proves promising as a clinical tool, given its quick and efficient methods.

Author Spotlight: Exploring the Complexities of Achilles Tendon Injuries &amp;#8212; Research and Future Directions

Measurement of Healthy and Injured Triceps Surae Morphology

Our research focuses on trying to understand the complexities of Achilles tendon injuries, specifically Achilles tendinopathy and achilles tendon ruptures. So we evaluate various domains of tendon health, such as pain and symptoms function, tendon structure, and psychological factors to kind of comprehensively identify individual differences in injured presentation and recovery. There is a current disconnect between those assessing structure and those assessing other measure of tendon health, such as symptoms and function.So with this protocol, in conjunction with additional evaluation methods to assess other tendon health domains, we'll provide a valuable insight into relationship between structure, function, symptoms, recovery of structure of after injury, and structural characteristics of health individuals and those with different injuries or comorbidities. The results from our lab and the use of ultrasound imaging methodology has really paved the way in recognizing the impacts of tendon elongation, the tendon healing longer after an achilles tendon rupture, and the important of minimizing this lengthening to optimize recovery. Additionally, the results have helped us really understand new scientific questions in the differences in recovery amongst patients with Achilles tendinopathy.

The measures in this protocol have been demonstrated to be reliable and valid10,20. Excellent reliability has been reported for extended field-of-view Achilles tendon length to gastrocnemius (interclass correlation coefficient (ICC): 0.944) and Achilles tendon length to soleus (ICC: 0.898)10. The minimal detectable change at the group level (MDCgroup) for Achilles tendon length measures is 0.43 cm for length to gastrocnemius and...

Watch this Scientific Journal Video about Measurement of Healthy and Injured Triceps Surae Morphology at JoVE.com

Ultrasound imaging is becoming more accessible in clinical and research settings, and a consistent protocol will be beneficial for comparison between studies and for clinical interpretations. This protocol for ultrasound evaluation is a valid and reliable method to evaluate Achilles tendon morphology in healthy, tendinopathic, and ruptured tendons.

Achilles tendon injuries occur throughout the lifespan and can negatively affect quality of life and overall health. Achilles tendinopathy is generally ...

measurement-of-healthy-and-injured-triceps-surae-morphology

Research

JoVE Journal

Medicine

Ultrasound Imaging of Achilles Tendon to Study Morphology

To begin, prepare for ultrasound imaging. Use B-mode ultrasound with a five centimeter linear array transducer. For a visualization of the tricep surae, set the frequency to 10 megahertz and the depth of the measurement to 3.5 centimeters.Adjust the foci between 0.75 and 1.75 centimeters with gain adjusted to 49 for optimal visualization of tissue. Place ultrasound gel on the posterior calcaneus. Holding the probe in the long axis, visualize the proximal calcaneal notch after aligning the notch with the midpoint of the ultrasound probe.Mark this location on the skin. To determine the position for measurement of Achilles tendon thickness in healthy individuals, measure two centimeters proximal from the proximal calcaneal notch and mark this location on the skin. For individuals with Achilles tendinopathy, visualize the thickest portion of the achilles tendon with the ultrasound probe on the long axis and mark this location on the skin.For individuals with Achilles tendinopathy without visible fusiform thickening, palpate the tendon and locate the position of most pain. Mark the skin at this location. For individuals with Achilles tendon rupture, visualize the location of rupture with the ultrasound probe in the long axis and mark this location on the skin.For the other limb, make the skin marking at the same distance from the proximal calcaneal notch as the involved limb. To measure gastrocnemius tendon length, hold the probe on the long axis. Using an extended field of view, begin the image at the calcaneus by visualizing the Achilles tendon insertion.Glide the probe proximally along the midline of the Achilles tendon towards the mark at the gastrocnemius midpoint until the myotendinous junction is seen. End the image here and take three images then measure the soleus tendon length using an extended field of view, beginning the image at the calcaneus by visualizing the Achilles tendon insertion. Glide the probe proximally along the midline of the Achilles tendon toward the mark at the soleus until the soleus myotendinous is junction is visualized.Take three images of the Achilles free tendon length. Next, to measure Achilles tendon thickness place the probe on the long axis on the skin marking. Use the B-mode view and take three images of Achilles tendon thickness.Measure Achilles tendon cross-sectional area. Place a gel standoff pad on the skin marking. Holding the probe on the short axis, take three images of the Achilles tendon cross section.Further, measure the soleus thickness by placing the probe on the long axis on the skin marking made for the soleus. Using B-mode view, visualize the anterior border of the soleus muscle and take three images for soleus thickness. To distinguish between the soleus and flexor hallucis longus, ask the participant to actively flex and extend the great toe.Observe the movement of the fibers of the flexor hallucis longus and no movement in the soleus fibers. To measure the gastrocnemius cross-sectional area, hold the ultrasound probe on the short axis and in line with the mark for the gastrocnemius. Visualize the medial border of the medial gastrocnemius and begin the image by gliding the probe from medial to lateral until the lateral border of the lateral gastrocnemius visualized.To capture the most medial aspect of the medial gastrocnemius, ask the participant to abduct their legs and internally rotate the hip slightly. Using the B-mode view, observe the calcifications within the achilles tendon. Calcifications are unattached from the calcaneus and appear as hypoechoic areas with a shadow below present in multiple planes of view.Next, determine the presence of bursitis visualized by a hypoechoic area deep to the Achilles tendon at the proximal calcaneus for retrocalcaneal bursitis. To assess neovascularization within the Achilles tendon, use the doppler setting on the ultrasound. Position the doppler box on the tendon and hold the ultrasound probe still, avoiding pressing or distending the tissue.Scan the length of the Achilles free tendon, being sure to assess each portion of the tendon without movement of the probe to prevent artifact. If there is vasculature visible within or in contact with the tendon, take three videos each for three seconds in the region with maximal blood flow.

Ultrasound Measurements of Achilles Tendon in Healthy and Injured Individuals

Begin by performing ultrasound recordings before measurement. To measure gastrocnemius tendon length, open the longer extended field of view tendon image. Measure from the most proximal point of the tendon insertion.That is, the proximal calcaneal notch to the gastrocnemius myotendinous junction. Next, open the shorter extended field of view tendon image to measure the soleus tendon length. Measure from the proximal calcaneal notch to the soleus myotendinous junction.Then, measure from the proximal calcaneal notch to two centimeters, with the end of the measurement on the deep border of the tendon. Measure from this point to the direct superficial aspect of the tendon to get the two centimeter tendon thickness. In the case of achilles tendinopathy, if the tendon is thickened at this two centimeter distance, locate a healthy area in the free tendon and take this measurement from the proximal calcaneal notch.Next, visually identify the borders of the achilles tendon and outline the circumference of the tendon to measure the tendon cross-sectional area. At the center of the image, measure the achilles tendon from the superficial border to the deep border of the tendon to get the tendon thickness. Also, measure from the superficial border to the deep border of the soleus muscle to get the soleus thickness.Further, to measure the gastrocnemius cross-sectional area, visualize the borders of both the medial and lateral heads of the gastrocnemius and outline them. Demographics of the dataset showed that the individuals post achilles tendon rupture had a lesser proportion of females, whereas the individuals with achilles tendinopathy had an even distribution of males and females. Further, the age of healthy participants was lesser than those with achilles tendinopathy and achilles tendon rupture.Healthy participants showed an achilles tendon mean thickness of 0.47 centimeters and CSA of 0.58 centimeter squared. There were no significant differences between the limbs and achilles tendon length measures for healthy individuals. However, for individuals with achilles tendinopathy, thicker tendons with larger CSA were observed compared to asymptomatic limbs.Also, individuals post achilles tendon rupture showed achilles tendon elongation and larger achilles tendon CSA in the involved limb compared to the uninvolved limb.

410 Views.  University of Delaware.  Ultrasound imaging is becoming more accessible in clinical and research settings, and a consistent protocol will be beneficial for comparison between studies and for clinical interpretations. This protocol for ultrasound evaluation is a valid and reliable method to evaluate Achilles tendon morphology in healthy, tendinopathic, and ruptured tendons. 

Ultrasound Evaluation of Achilles Tendon Morphology

Summary