The anatomical variant of high soleus muscle may predispose to tendinopathy: a preliminary MR study

Abstract

Purpose This study aimed to examine the anatomic variations at the level of the distal soleus musculotendinous junction and the possible association between the length of the free tendon and the development of symptomatic Achilles tendinopathy. Methods We retrospectively assessed 72 ankle MRI studies with findings of Achilles tendinopathy (study group, 26 females/46 males, mean age 52.6 ± 10.5 years, 30 right/42 left) and 72 ankle MRI studies with normal Achilles tendon (control group, 32 females/40 males, mean age 35.7 ± 13.7 years, 42 right/30 left side). We measured the distance from the lowest outline of the soleus myotendinous junction to the proximal outline of the Achilles tendon insertion (length of the free tendon, diameter a) and to the distal outline of the insertion (distance B). We also measured the maximum thickness of the free tendon (diameter c) and the distance between the levels of maximum thickness to the proximal outline of the Achilles tendon insertion (distance D). All measurements were assessed twice. Statistical analysis was performed using independent t test. Results Distances A and B were significantly larger in tendinopathic tendons (59.7 and 83.4 mm, respectively) than normal Achilles tendons (38.5 and 60.8 mm, respectively) (p = 0.001). Mean distance C was larger in tendinopathic than normal tendons (11.2 versus 4.9 mm). Distances C and D were significantly larger in males than females. There was no significant difference in the measurements between sides. Conclusion There is wide anatomical variation in the length of the free Achilles tendon. Tendinopathy may be associated with the thicker free part of the Achilles tendon. The anatomical variant of the high soleus musculotendinous junction resulting in a longer free Achilles tendon may be a predisposing factor to the development of tendinopathy.

Evaluation of the morphometric features of Achilles tendon with tendinopathy: an MRI study

“…This may mean that as the length of the Achilles tendon increases, its stability decreases. Similar to our study, Drakonaki et al [10] found that Achilles tendon length (59.7 mm) was significantly higher in patients with tendinopathy compared to the control group (38.5). Weber et al [19] measured Achilles tendons in pathologic and control groups and found 83.2 mm in the pathologic group and 45.9 mm in the control group.…”

“…The presence of morphologic and signal changes in the tendon has increased the accuracy of tendinopathy diagnosis. [10,11] Furthermore, understanding the anatomy and variations of the Achilles tendon and surrounding soft tissues improves surgical techniques and reduces the risk of iatrogenic injury. [12] The aim of this study was to demonstrate the morphologic features and anatomic variations of the gastrocnemius and soleus tendons and the relationship between these variations and tendinopathy using magnetic resonance imaging.…”

An Identical Twin Study on Human Achilles Tendon Adaptation: Regular Recreational Exercise at Comparatively Low Intensities Can Increase Tendon Stiffness

“…Also, ultrasound would be a more precise method to determine free Achilles tendon length. Previous research indicates considerable variation in the length of the free Achilles tendon length ( Drakonaki et al, 2021 ), but also between runners and non-runners ( Devaprakash et al, 2020 ). Although we followed a standardized protocol to determine the middle of the free Achilles tendon, caution must be applied, as our approach does not guarantee that the stiffness measurements were acquired within the free portion of the tendon.…”

The Distal Free Achilles Tendon Is Longer in People with Tendinopathy than in Controls: A Retrospective Case-Control Study

“…This observation has been confirmed by two recent studies. Both found even larger differences between the cases (59.7 mm and 60.0 mm) and controls (38.5 mm and 39.3 mm) [ 20 , 26 ] However, they did not consider differences in height and weight, so there was the possibility the tendinopathy group was simply taller or heavier. This study also builds on the previous two findings by distinguishing between insertional and midportion Achilles tendinopathy, as risk factors likely differ for these two entities.…”

“…Using magnetic resonance imaging (MRI), the structural differences can be investigated between those with and without tendinopathy [11,12]. It has been well established that those with tendinopathy have tendons with significantly larger cross-sectional area and anterior-posterior diameter compared to healthy controls [7,[13][14][15][16][17][18][19][20][21][22][23][24][25][26]. is is thought to be mainly due to the increased fluid content and disordered collagen structure as an adaptive and/or reparative response [27][28][29][30][31][32][33][34][35].…”