Measurement of Healthy and Injured Triceps Surae Morphology

Summary

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.

Abstract

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 symptoms and lower physical activity levels, as well as 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'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.

Introduction

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'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 exhibi....

Protocol

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

1. Ask the participant to be.......

Discussion

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.......

Materials

Name	Company	Catalog Number	Comments
Aquaflex Stand Off Pad	Parker Laboratories	E8317C
Aquasonic ultrasound Gel	Parker Laboratories	E8365AF
Linear Array Ultrasound Probe L4-12t-RS	GE Healthcare	5495987
LOGIC e Ultrasound	GE Healthcare	E8349PA
Osirix Dicom Viewer	Pixmeo SARL		Software for measurements