Speckle tracking in healthy and surgically repaired human Achilles tendons at different knee angles-A validation using implanted tantalum beads

Abstract

The exact injury mechanism of Achilles tendinopathy remains unknown, but sliding of fascicles relative to each other during loading may be an important factor. This study validated the motion of ultrasound speckles against actual tendon movement using tantalum beads as reference markers. In addition, the effect of different knee joint angles (ie, muscle activation) on tendon tissue shear and displacement during a single heel rise was investigated. The 10 male participants had tantalum beads inserted in the tendon during surgery for a unilateral Achilles tendon rupture at least 1 year prior to the study. Ultrasound speckle displacement in the tissue surrounding the bead correlated strongly with displacement of the bead (R2 ≥ .9987). Speckle tracking systematically underestimated the displacement of the tendon tissue with a typical error of 1.1%‐2.7%. There was a significant difference in displacement between the superficial and deep tendon layer for the 3 exercises in the healthy, but not in the surgically repaired Achilles tendon. The displacement difference was significantly greater when performing heel rises with the knee flexed 100° compared to knee flexed 40°. In conclusion, speckle tracking appears to be a valid approach to investigate intratendinous displacement.

Biplanar ultrasound investigation of in vivo Achilles tendon displacement non-uniformity

“…In addition, also Bogaerts et al recently reported that knee joint ankle did not have an effect on regional Achilles tendon tissue displacement patterns during isometric contractions as measured in the sagittal plane . In contrast, while Beyer et al also observed that displacement of the anterior region of the Achilles tendon remained almost similar between plantarflexion tasks performed in knee extended and flexed (100° flexion) postures, the posterior region experienced smaller displacement in the knee flexed posture resulting in greater relative motion within the Achilles tendon in the knee flexed posture . However, in the study by Beyer et al, the outcome may be affected by the fact that loading conditions greatly differed between the knee extended and flexed postures, whereas in the current study, a maximal isometric contraction was done in both joint postures.…”

“…Recent advances in dynamic ultrasound imaging and various speckle tracking algorithms permit the measurement of localized tendon tissue displacements within the Achilles tendon . With the help of ultrasound speckle tracking, several recent in vivo studies have revealed non‐uniform motion within the Achilles tendon during passive joint rotations, active muscle contractions, and during locomotion . These observations of non‐uniform tendon motion, thus far isolated to sagittal plane measurements (ie, antero‐posterior differences), are consistent with sliding between adjacent subtendons.…”

Early development of tendinopathy in humans: Sequence of pathological changes in structure and tissue turnover signaling

“…25 A custom Matlab script (Matlab R2016b, The MathWorks Inc, USA) using a cross-correlation algorithm was used to track the tendon insertions on patella and tibia. 26 Around 10-20 tracking nodes were placed on either apex patellar or tuberositas tibia and tracking was performed twice at each location. Tendon deformation was determined as the distance between the insertions and was then correlated with force measurements using a custom-made excel template to generate a force-deformation curve.…”

Musculoskeletal application and validation of speckle-tracking ultrasonography

“…A recent study on human Achilles tendons used STU to investigate intratendinous displacement following surgery for unilateral tendon rupture [21]. Implanted tantalum beads were used to follow displacement of tendon speckles, but this was not feasible in the present study.…”