Elasticity of the Achilles Tendon in Individuals With and Without Plantar Fasciitis: A Shear Wave Elastography Study

Abstract

The elastic properties of the Achilles tendon (AT) are altered in local injury or other diseases and in response to changes in mechanical load. Recently, elastography has been used to evaluate variations in tendon elastic properties, mainly among healthy individuals or athletes. Therefore, this study evaluated the biomechanical changes in ATs in individuals with and without plantar fasciitis (PF). The purposes were as follows: (1) to evaluate the passive stiffness of three regions of the AT which defined as 0 (AT0 cm), 3 (AT3 cm), and 6 cm (AT6 cm) above the calcaneal tuberosity in participants with and without PF, (2) to investigate the interplay between the passive stiffness in patients with PF and pain, (3) to detect optimal cut-off points of stiffness of the AT in assessing individuals with chronic PF, and (4) to determine the correlation between the plantar fascia thickness (PFT) and pain. This cross-sectional study included 40 participants (mean age = 51 ± 13 years). When the ankle was in a relaxed position, patients with PF experienced increased passive stiffness in AT0 cm (p = 0.006) and AT3 cm (P = 0.003), but not in the neutral position. Significant correlations were observed between pain and stiffness of AT (AT0 cm r = 0.489, P = 0.029; AT3 cm r = 487, P = 0.030; AT6 cm r = 0.471, P = 0.036), but not in the PFT (P = 0.557). Optimal cut-off stiffness was AT (452 kPa) in the relaxed ankle position. The plantar fascia of patients with PF was significantly thicker than that of the controls (P < 0.001). Findings from the present study demonstrate that tendon stiffness is a good indicator of the clinical situation of patients with PF. Monitoring passive tendon stiffness may provide additional information to assess severity of the condition and guide therapeutic. The treatment programs for PF should also be tailored to the distal AT, as conventional therapy might not be targeted to tight tendons.

Reliability of shear wave elastography for the assessment of gastrocnemius fascia elasticity in healthy individual

“…Only the dominant leg of each participant was studied 16 , 17 , 19 , 20 , and participants were asked to rest for 10 min before testing. In addition, participants were asked to lie down in a prone position on the treatment bed, with their feet fully extended and projecting slightly beyond the edge of the bed, their knees fully extended, and their upper limbs naturally placed along the sides of the body 16 .…”

“…The shear modulus of the MGF and LGF was quantified at neutral position (90°) and relaxed position of the ankle joint. The neutral position representing the ankle joint was fixed at the neutral anatomical position, while the relaxed position representing the ankle joint was fully relaxed 16 , 17 , 19 , 20 . The angle of the ankle joint was measured with a handheld goniometer.…”

“…The shear moduli of the MGF and LGF were measured on the medial and lateral sides, respectively, in the proximal 30% of the region between the calcaneus and the popliteal fossa. Length was measured with a tape measure 16 , 17 , 19 , 20 . The placement direction of the scanner was parallel to the line connecting the calcaneus and the medial or lateral popliteal fossa.…”

“…Our previous studies have shown that USWE is an effective and reliable technique for estimating the elastic properties of muscles and tendons, such as the gastrocnemius and Achilles tendon, and reflecting the biomechanical properties of muscles and tendons 18 . In addition, USWE was used to evaluate the passive behavior of plantar flexors during passive dorsiflexion 20 . They found that the shear modulus of the lower leg is inhomogeneous between muscles and displays differences during passive dorsiflexion 20 .…”

“…In addition, USWE was used to evaluate the passive behavior of plantar flexors during passive dorsiflexion 20 . They found that the shear modulus of the lower leg is inhomogeneous between muscles and displays differences during passive dorsiflexion 20 . However, USWE has not been used to quantify the shear modulus of the GDF, including the changes in its shear modulus during passive dorsiflexion.…”