Characterisation of Knee Brace Migration and Associated Skin Deformation During Flexion by Full-Field Measurements

Pierrat, Baptiste; Millot, Carine; Molimard, Jérôme; Navarro, Laurent; Calmels, P.; Édouard, Pascal; Avril, Stéphane

doi:10.1007/s11340-014-9947-2

Cited by 16 publications

(7 citation statements)

References 19 publications

(20 reference statements)

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“…Another effect that causes misalignment and leads to discomfort issues is brace slippage. 21 A study by Brownstein 22 found a maximal migration of 11 mm after only 15 min of exercises. The misalignment of the rotation axes of knee and brace caused by the different kinematics and through brace slippage might influence structures within the knee.…”

mentioning

confidence: 98%

The effect of knee brace misalignment on the anterior cruciate ligament

Hacker¹,

Schall²,

Ignatius³

et al. 2019

Prosthetics &Amp; Orthotics International

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Background: Protective knee braces are used for rehabilitation or prevention. Due to poor patient compliance or slippage, the brace might be misaligned with the knee axis. Objectives: Does a misaligned knee brace stress the anterior cruciate ligament? Study design: It is an experimental study. Methods: A strain sensor was implanted on the anterior cruciate ligament in eight limbs. The limbs were mounted in a knee simulator, muscle forces were applied and a cyclic motion from 10° to 60° flexion was performed under three conditions: unbraced, braced and with a misaligned brace. Outcome measures: The outcome measures were anterior cruciate ligament strain and three-dimensional kinematics of the knee joint. Results: The correctly aligned brace significantly reduced the anterior cruciate ligament strain at 10° compared to the unbraced condition from 0% to −1.54% (standard deviation = 1.4). The misaligned brace neutralised the effect of bracing to −0.06% (standard deviation = 1.1) anterior cruciate ligament strain. At 60° flexion angle, bracing had no statistically significant effect on the anterior cruciate ligament strain compared to the unbraced knee: −2.58% (standard deviation = 0.8) versus −1.64% (standard deviation = 1.0). The anterior cruciate ligament in the misaligned braced knee at 60° flexion with a strain of −1.1% (standard deviation = 0.9) was significantly more stressed than in the correctly aligned condition. An effect of bracing on knee kinematics was not detected. Conclusion: A correctly aligned knee brace reduced anterior cruciate ligament strain. By contrast, a misaligned brace tended to increase the anterior cruciate ligament strain compared to the unbraced knee. Clinical relevance The correct alignment of the brace was identified as a key factor decisively influencing the effectiveness of bracing.

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mentioning

confidence: 98%

The effect of knee brace misalignment on the anterior cruciate ligament

Hacker¹,

Schall²,

Ignatius³

et al. 2019

Prosthetics &Amp; Orthotics International

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“…High interaction forces may result in skin sores, additional pain, or injuries (Chen et al, 2016 ; Gorgey, 2018 ). Studies such as Pierrat et al ( 2015 ); Anil Kumar et al ( 2019 ); Serrancoli et al ( 2019 ) have shown that interaction forces are strongly related to safety, comfort, and quality of walking with lower limb orthotics/exoskeletons.…”

Section: Introductionmentioning

confidence: 99%

Evaluating Knee Mechanisms for Assistive Devices

Patrick

Kumar²,

Hur³

2022

Front. Neurorobot.

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State-of-the-art knee braces use a polycentric mechanism with a predefined locus of the instantaneous center of rotation (centrode) and most exoskeleton devices use a knee mechanism with a single axis of rotation. However, human knees do not share a common centrode nor do they have a single axis. This leads to misalignment between the assistive device's joint axis and the user's knee axis, resulting in device migration and interaction forces, which can lead to sores, pain, and abandonment of the device over time. There has been some research into self-aligning knee mechanisms; however, there is a lack of consensus on the benefit of these mechanisms. There is no research that looked purely at the impact of the knee mechanisms, either. In this article, we compare three different knee brace mechanisms: single axis (SA), polycentric with predefined centrode (PPC), and polycentric with a self-aligning center of rotation (PSC). We designed and conducted an experiment to evaluate different joint mechanisms on device migration and interaction forces. Brace material, weight, size, cuff design, fitment location, and tightness were consistent across trials, making the knee joint mechanism the sole variable. The brace mechanisms had no significant effect on walking kinematics or kinetics. However, the PPC brace had greater interaction forces on the top brace strap than the SA and PSC. The PSC and SA had significantly lower interaction forces on the bottom strap compared to the PPC brace. The PSC had significantly less migration than both the SA and PPC braces. These results show that a PPC mechanism may not be beneficial for a wide range of users. This also shows that the PSC mechanisms may improve mechanism alignment and lessen device migration.

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“…Thus, it is of great importance to have measurements of pressure and deformation fields all around the trunk. Full-field measuring techniques have attracted interest in many biomechanical studies, among them, pressure fields on feet [30] or buttocks [31] or strain fields on knee braces [32] or on the calf [33] but, to our knowledge, no direct application on lumbar belts exists. Moreover, it seems that no simultaneous pressure and strain field measurement on a compression device has been reported.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of a Full-Field Measurements-Based Protocol for the Biomechanical Study of a Lumbar Belt: A Case Study

Bonnaire

Han

Convert³

et al. 2022

Biomechanics

Self Cite

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Low back pain represents a major economic and societal challenge due to its high prevalence. Lumbar orthoses are one of the recommended treatments. Even if previous results showed their clinical effects, the detailed mode of action is still poorly known, making the device design difficult. A renewed instrumentation and experimental protocol should bring better insight into the lumbar brace–trunk mechanical interaction. This instrumentation should give detailed information on the basic physical or geometrical parameters: the pressure applied on the trunk, the body shape and the strain in the belt. The principal objective of this study was to propose and validate a new measurement protocol, based on pressure mapping systems and full-field shape and strain measurement. The feasibility of the protocol was tested along with its validity and repeatability. The influence of various parameters, which could cause changes in the measurements, was tested with six different belt configurations on one subject. Measurements were also performed to study the impact of posture on pressure and strain. Both pressure and strain appeared to be asymmetric from left to right. The pressure applied by the lumbar belt on the back varies with breathing and with posture. This study showed that full-field measurements were necessary to render the high variability of pressure or strain around the trunk, under recommendations of their use to guarantee a satisfying repeatability.

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Characterisation of Knee Brace Migration and Associated Skin Deformation During Flexion by Full-Field Measurements

Cited by 16 publications

References 19 publications

The effect of knee brace misalignment on the anterior cruciate ligament

The effect of knee brace misalignment on the anterior cruciate ligament

Evaluating Knee Mechanisms for Assistive Devices

Feasibility of a Full-Field Measurements-Based Protocol for the Biomechanical Study of a Lumbar Belt: A Case Study

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