Shear wave elastography assessment and comparison study of the Achilles tendons in optimally conditioned asymptomatic...

To assess the functional parameters of the Achilles tendons among asymptomatic college level athletes using shear wave elastography (SWE) and to describe the relationship to athlete demographics and anthropometric lower extremity measurements.

Sixty-five athletes were included in this IRB-approved study. SWE measurements were made on two tendon positions (neutral state and active maximum dorsiflexion) with two different probe orientations (longitudinal and transverse). Associations were assessed with BMI, tibial/foot length, type of sports, and resting/maximal dorsiflexion-plantar flexion angles.

Thirty-five (53.8%) males and 30 (46.2%) females with an overall mean age of 20.9 years (± 2.8), mean height of 176 cm (± 0.11), and mean weight of 74.1 kg (± 12) were studied. In the neutral state, the mean wave velocity of 7.5 m sec^-1 and the mean elastic modulus of 176.8 kPa were recorded. In active maximum dorsiflexion, the mean velocity was 8.3 m sec^-1 and mean elastic modulus was 199 kPa. On the transverse view, the mean velocity and elastic measurements were significantly lower (p = 0.0001). No significant differences in SWE parameters were seen between male and female athletes regardless of probe orientation (p < 0.05) with SWE values being higher in the running group vs non-running group (p < 0.05). In neutral state, longitudinal SWE measurements correlated with the tibia-foot length whereas transverse measurements correlated with the tendon diameter and ankle resting angle (ARA) (p < 0.005).

SWE can distinguish functional differences in Achilles tendon stiffness between athletes engaged in running-intensive sports compared with other athletes.