Ligament Shear Wave Speeds Are Sensitive to Tensiometer-Tissue Interactions: A Parametric Modeling Study

Blank, Jonathon; Thelen, Darryl G.; Roth, Joshua D.

doi:10.1007/978-3-030-43195-2_5

Cited by 5 publications

(5 citation statements)

References 12 publications

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“…Between the transducer input and first measurement location, the wave is free to displace the tendon. Once the wave reaches the first location, the tendon motion is subject to the response of the tendon–sensor system combined, and this behavior is measured at the second measurement location [ 21 ]. By limiting the measurement to a single point, the measured response is closer to the unobstructed tendon.…”

Section: Discussionmentioning

confidence: 99%

A Single-Sensor Approach for Noninvasively Tracking Phase Velocity in Tendons during Dynamic Movement

Schmitz,

Thelen,

Cone

2023

Micromachines

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Shear wave tensiometry is a noninvasive method for directly measuring wave speed as a proxy for force in tendons during dynamic activities. Traditionally, tensiometry has used broadband excitation pulses and measured the wave travel time between two sensors. In this work, we demonstrate a new method for tracking phase velocity using shaped excitations and measurements from a single sensor. We observed modulation of phase velocity in the Achilles tendon that was generally consistent with wave speed measures obtained via broadband excitation. We also noted a frequency dependence of phase velocity, which is expected for dispersive soft tissues. The implementation of this method could enhance the use of noninvasive wave speed measures to characterize tendon forces. Further, the approach allows for the design of smaller shear wave tensiometers usable for a broader range of tendons and applications.

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Section: Discussionmentioning

confidence: 99%

A Single-Sensor Approach for Noninvasively Tracking Phase Velocity in Tendons during Dynamic Movement

Schmitz,

Thelen,

Cone

2023

Micromachines

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“…Our numerical experiments showed that the uncertainty in travel time could be estimated from the strength of correlation ( Figure 5 ), a relationship that was used to describe the noise processes in the Kalman filter model. Further study is needed to investigate non-noise processes more fully, e.g., dispersion, that can contribute to decorrelation from in situ tensiometry measurements [ 22 , 23 ].…”

Section: Discussionmentioning

confidence: 99%

A Kalman Filter Approach for Estimating Tendon Wave Speed from Skin-Mounted Accelerometers

Schmitz

Thelen

Cone

2022

Sensors

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Shear wave tensiometry is a noninvasive approach for assessing in vivo tendon forces based on the speed of a propagating shear wave. Wave speed is measured by impulsively exciting a shear wave in a tendon and then assessing the wave travel time between skin-mounted accelerometers. Signal distortion with wave travel can cause errors in the estimated wave travel time. In this study, we investigated the use of a Kalman filter to fuse spatial and temporal accelerometer measurements of wave propagation. Spatial measurements consist of estimated wave travel times between accelerometers. Temporal measurements are the change in wave arrival at a fixed accelerometer between successive impulsive taps. The Kalman filter substantially improved the accuracy of estimated wave speeds when applied to simulated tensiometer data. The variability of estimated wave speed was reduced by ~55% in the presence of random sensor noise. It was found that increasing the number of accelerometers from two to three further reduced wave speed errors by 45%. The use of redundant accelerometers (>2) also improved the robustness of wave speed measures in the presence of uncertainty in accelerometer location. We conclude that the use of a Kalman filter and redundant accelerometers can enhance the fidelity of using shear wave tensiometers to track tendon wave speed and loading during movement.

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“…The level of this controlled force was set to minimally influence the shear wave speeds. 32 We measured the controlled force of each component using a load cell (LC101, Omegadyne Inc., with reported linearity = 0.25 N). The piezoelectric tapping device (PK4JQP1, Thorlabs Inc, Newton, NJ) induced shear waves in each specimen by delivering 20-μm impulsive taps across the width of the ligament at a tap rate of 10 Hz.…”

Section: Methodsmentioning

confidence: 99%

“…Next, we mounted the three components of the shear wave tensiometer, which housed the piezoelectric tapping device and two accelerometers, in a 3D‐printed structure that pressed each component against the outer surface of the ligament with a controlled force of 1.4 ± 0.2 N (Figure 1). The level of this controlled force was set to minimally influence the shear wave speeds (i.e., maintain coupled transverse motion of the accelerometers and the ligament with minimal alteration of the local stresses) 34 . We measured the controlled force of each component using a load cell (LC101; Omegadyne Inc., with reported linearity = 0.25 N).…”

Section: Methodsmentioning

confidence: 99%

“…The level of this controlled force was set to minimally influence the shear wave speeds (i.e., maintain coupled transverse motion of the accelerometers and the ligament with minimal alteration of the local stresses). 34 We measured the controlled force of each component using a load cell (LC101; Omegadyne Inc., with reported linearity = 0.25 N). The piezoelectric tapping device (PK4JQP1; Thorlabs Inc.) induced shear waves in each specimen by delivering micron-scale square wave taps with a 50% duty cycle across the width of the ligament at a tap rate of 10 Hz.…”

Section: Methodsmentioning

confidence: 99%

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Shear wave tensiometry tracks reductions in collateral ligament tension due to incremental releases

Blomquist

Blank

Schmitz

et al. 2022

Journal Orthopaedic Research

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Surgeons routinely perform incremental releases on overly tight ligaments during total knee arthroplasty (TKA) to reduce ligament tension and achieve their desired implant alignment.However, current methods to assess whether the surgeon achieved their desired reduction in the tension of a released ligament are subjective and/or do not provide a quantitative metric of tension in an individual ligament. Accordingly, the purpose of this study was to determine whether shear wave tensiometry, a novel method to assess tension in individual ligaments based on the speed of shear wave propagation, can detect changes in ligament tension following incremental releases. In seven medial and eight lateral collateral porcine ligaments (MCL and LCL, respectively), we measured shear wave speeds and ligament tension before and after incremental releases consisting of punctures with an 18-gauge needle. We found that shear wave speed squared decreased linearly with decreasing tension in both the MCL (r 2 avg = 0.76) and LCL (r 2 avg = 0.94). We determined that errors in predicting tension following incremental releases were 24.5 N and 12.2 N in the MCL and LCL, respectively, using specimen-specific calibrations.These results suggest shear wave tensiometry is a promising method to objectively measure the tension reduction in released structures. Clinical Significance: Direct, objective measurements of the tension changes in individual ligaments following release could enhance surgical precision during soft tissue balancing in TKA. Thus, shear wave tensiometry could help surgeons reduce the risk of poor outcomes associated with overly tight ligaments, including residual knee pain and stiffness.

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Ligament Shear Wave Speeds Are Sensitive to Tensiometer-Tissue Interactions: A Parametric Modeling Study

Cited by 5 publications

References 12 publications

A Single-Sensor Approach for Noninvasively Tracking Phase Velocity in Tendons during Dynamic Movement

A Single-Sensor Approach for Noninvasively Tracking Phase Velocity in Tendons during Dynamic Movement

A Kalman Filter Approach for Estimating Tendon Wave Speed from Skin-Mounted Accelerometers

Shear wave tensiometry tracks reductions in collateral ligament tension due to incremental releases

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