Elsevier

Physical Therapy in Sport

Volume 35, January 2019, Pages 122-126
Physical Therapy in Sport

Original Research
Comparison of the sonographic features of the Achilles Tendon complex in patients with and without achilles tendinopathy: A case-control study

https://doi.org/10.1016/j.ptsp.2018.12.003Get rights and content

Highlights

  • We evaluated and quantified with ultrasound imaging the Achilles tendon thickness (ATT).

  • ATT decrease in gastrocnemius-soleus PA and Kager's fat pad length showed in patients with chronic mid-portion ATT.

  • Preventive care in athletes are very important to improve foot and general health.

Abstract

Aim

The aim of the present study was to evaluate and quantify with ultrasound imaging (USI) the Achilles tendon thickness, cross-sectional area (CSA), Kager's fat pad length and gastrocnemius-soleus pennation angle (PA) between chronic mid-portion Achilles tendinopathy (AT) and healthy subjects.

Methods

A total sample of 143 individuals (age: 41.3 ± 12.0 y; height: 1.74 ± 0.0 m; weight: 75.0 ± 11.4 kg; body mass index, BMI: 24.4 ± 2.6 kg/m2) was recruited and divided in two groups: chronic mid-portion AT group (n = 71) and a healthy group (n = 72).

Results

The thickness and CSA at 4 cm and 6 cm from the calcaneus was increased showing statistically significant differences (P < .01) in favor the tendinopathy group. For the gastrocnemius-soleus PA and Kager's fat pad length, significant differences (P < .01) were observed for a decrease in favor of the tendinopathy group.

Conclusions

This study reported an increase of Achilles tendon thickness and CSA at 4 cm and 6 cm from the calcaneus as well as a decrease in gastrocnemius-soleus PA and Kager's fat pad length in patients with chronic mid-portion AT.

Introduction

The Achilles tendon is the strongest and largest tendon in the whole human body. This structure is subject to modifications depending to the tensile loads during its contraction or elongation, make it susceptible to overuse injuries (Nadeau, Desrochers, Lamontagne, Larivière, & Gagnon, 2016).

Achilles tendinopathy (AT) is a clinical disease characterized by pain, swelling, morning stiffness and a lack of functionality in the lower limb (Lopes, Hespanhol Junior, Yeung, & Costa, 2012). This syndrome reported an incidence rate of 2.35 and 2.16 per 1000 in general population (Albers, Zwerver, Diercks, Dekker, & Van den Akker-Scheek, 2016). Overuse is the primary cause of AT, starting with lightly tendon adaptations and finishing with degenerative processes (Cook & Purdam, 2009). Degeneration is very common in the mid-portion in this population (van Dijk, van Sterkenburg, Wiegerinck, Karlsson, & Maffulli, 2011), and specially this area seems to present a blow flow decrease (Chen et al., 2009).

Structural alterations have been identified in individuals with AT, Shaikh et al. (Shaikh et al., 2012) showed an increased tendon thickness in runners with AT symptoms. Arya and Kulig (8) reported an increase in cross sectional area (CSA) in tendinopathic tendons. In addition, Docking and Cook observed a greater Achilles CSA compared with healthy individuals. Padhiar et al. (Padhiar, Al-Sayeagh, Chan, King, & Maffulli, 2008) observed that subjects with AT are more likely to have a decreased pennation angle (PA) of the soleus fibers in the pathologic side.

Several authors reported a reduced mechanical properties in weight-bearing tendons in subjects with AT (Arya & Kulig, 2010). Kongsgaard et al. (Kongsgaard et al., 2010) showed a higher tendon strain and a lower tendon stiffness in subjects with AT compared with controls. In addition, Wang et al. (Wang, 2006) argued that these reduced mechanical features are a consequence of changes in the tendon cellular structure.

Ultrasound imaging (USI) have been widely used to quantify the length, thickness and CSA of the tendon, muscular and connective tissues in different structures. B- mode is considered superior to magnetic resonance imaging (MRI) for assess structural changes in AT (Fredberg & Stengaard-Pedersen, 2008). USI is considered as a non-invasive, safe, rapid and relatively inexpensive technique which provides a complete examination of the tendon and surrounding structures (Shaikh et al., 2012) (8) (Padhiar et al., 2008) Several authors described by USI healthy Achilles tendons with well-organized and parallel collagen fibers with hyperechoic bright bands and hypoechoic dark bands from the extracellular matrix (Khan, Cook, Bonar, Harcourt, & Astrom, 1999) ((Sharma & Maffulli, 2006)) Sharma and Maffulli ((Sharma & Maffulli, 2006)) reported a disorganization areas of the collagen fibers and a thickened and hypoechoic portion in tendons from individuals with AT. Nadeau et al. (Nadeau et al., 2016) reported that the use of the USI has evolved in the last recent years, being able to provide high quality images to quantify structures and angles. For example, the maximum thickness from a tendon is relatively easy to measure with a two-point digital caliper function on the USI machine. In addition, Hertzberg et al. (Hertzberg et al., 2000) indicated that these measurements are influenced by the evaluator's experience to recorded and interpret the images.

Regarding the literature, several studies have shown a moderate to good test-retest reliability of the Achilles tendon (O'Connor et al., 2004) ((Fredberg, Bolvig, Andersen, & Stengaard-Pedersen, 2008)) Provide information about the tendon structure, such as thickness or CSA is becoming essential to the clinicians and researches for the diagnosis and to observe the evolution to the different treatments.

The aim of the present study was to evaluate and quantify with USI the Achilles tendon thickness, CSA, Kager's fat pad length and gastrocnemius-soleus PA between chronic mid-portion AT and healthy subjects. It was hypothesized that in presence of tendinopathy, structural alterations were observed and quantify with USI, such an increase of CSA and a decrease of the gastrocnemius PA.

Section snippets

Design

A cross-sectional observational study has been carried out from January to December 2017, following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) recommendations (Welch et al., 2015).

Sample size calculation

A sample size calculation was performed by the difference between two groups with the G*Power 3.1.9.2 software and based on the thickness (mm) at 4 cm from the calcaneus variable of a pilot study (n = 42) with 2 groups (mean ± SD), 21 subjects with chronic mid-portion AT

Results

Regarding the Table 1, sociodemographic data showed statistically significant differences (P < .05) for the body mass index (BMI) between groups and did not show statistically significant differences (P > .05) for the age, weight and height between groups. Considering the Table 2, ultrasound measurements of the thickness and CSA at 4 cm and 6 cm from the calcaneus increased showing statistically significant differences (P < .01) in favor the tendinopathy group. For the gastrocnemius-soleus PA

Discussion

This research provides useful information regarding the Achilles tendon complex in individuals with AT and controls. Conventional ultrasound evaluations, such Achilles tendon thickness and CSA, were considered valid and reliable measures for patients with AT. Syha et al. (Syha et al., 2007) suggested that B-mode USI could be a new gold standard for quantification alterations in chronic Achilles tendons. Moreover, this research contemplates a new approach to measure and quantify the

Conclusions

This study reported an increase of Achilles tendon thickness and CSA at 4 cm and 6 cm from the calcaneus as well as a decrease in gastrocnemius-soleus PA and Kager's fat pad length in patients with chronic mid-portion AT.

Conflicts of interest and Source of Funding

There are no conflicts of interest or Source of Funding.

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