Wavelet analysis in the diagnosis of knee instability: early results from a novel assessment method

Research output: Contribution to conferencePoster

Abstract

Introduction: Instability in the knee following total knee arthroplasty (TKA) is a leading cause for dissatisfaction, often requiring revision surgery1. However, instability remains a symptom with no corresponding objective measure. The purpose of this study was to identify quantifiable differences in frontal plane accelerations at the knee between subjectively “stable” and “unstable” TKA patients. Methods: Post-operative TKA patients with symptomatic instability were recruited from a national orthopaedic centre, along with asymptomatic post-operative TKA patients, and healthy controls. Frontal plane knee accelerations were measured using an accelerometer mounted on the lateral aspect of the proximal lower leg. Individual strides were extracted, and continuous wavelet transform (CWT) of the accelerations were performed, with the absolute value of the CWT coefficient examined for differences between groups. Results & Discussion: 10 controls, 9 “stable”, and 7 “unstable” participants were tested. Increased CWT coefficients were found between 50% and 80% of stride (heel strike to heel strike), and between 4 and 8Hz, in the “unstable” TKA group in comparison with the “stable” and control groups. This corresponds to increased oscillation at the proximal tibia frontal plane during early swing phase, consistent with reduced stiffness and increased contact point movement in subjectively unstable osteoarthritic knees2,3. Conclusion: Accelerations in the frontal plane of the knee during swing phase corresponds to subjective instability in the TKA. This portable and inexpensive technology has potential for use in clinics to quantify instability in the unhappy TKA.

Conference

ConferenceBioMedEng18
Abbreviated titleBioMedEng
CountryUnited Kingdom
CityLondon
Period6/09/187/09/18
Internet address

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Arthroplasty
Wavelet analysis
Wavelet transforms
Point contacts
Orthopedics
Accelerometers
Stiffness

Keywords

  • wavelet analysis
  • knee instability
  • total knee arthroplasty

Cite this

Wallace, D. T., Clarke, J. V., & Riches, P. E. (2018). Wavelet analysis in the diagnosis of knee instability: early results from a novel assessment method. Poster session presented at BioMedEng18, London, United Kingdom.
Wallace, D.T. ; Clarke, J.V. ; Riches, P.E. / Wavelet analysis in the diagnosis of knee instability : early results from a novel assessment method. Poster session presented at BioMedEng18, London, United Kingdom.1 p.
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abstract = "Introduction: Instability in the knee following total knee arthroplasty (TKA) is a leading cause for dissatisfaction, often requiring revision surgery1. However, instability remains a symptom with no corresponding objective measure. The purpose of this study was to identify quantifiable differences in frontal plane accelerations at the knee between subjectively “stable” and “unstable” TKA patients. Methods: Post-operative TKA patients with symptomatic instability were recruited from a national orthopaedic centre, along with asymptomatic post-operative TKA patients, and healthy controls. Frontal plane knee accelerations were measured using an accelerometer mounted on the lateral aspect of the proximal lower leg. Individual strides were extracted, and continuous wavelet transform (CWT) of the accelerations were performed, with the absolute value of the CWT coefficient examined for differences between groups. Results & Discussion: 10 controls, 9 “stable”, and 7 “unstable” participants were tested. Increased CWT coefficients were found between 50{\%} and 80{\%} of stride (heel strike to heel strike), and between 4 and 8Hz, in the “unstable” TKA group in comparison with the “stable” and control groups. This corresponds to increased oscillation at the proximal tibia frontal plane during early swing phase, consistent with reduced stiffness and increased contact point movement in subjectively unstable osteoarthritic knees2,3. Conclusion: Accelerations in the frontal plane of the knee during swing phase corresponds to subjective instability in the TKA. This portable and inexpensive technology has potential for use in clinics to quantify instability in the unhappy TKA.",
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Wavelet analysis in the diagnosis of knee instability : early results from a novel assessment method. / Wallace, D.T.; Clarke, J.V.; Riches, P.E.

2018. Poster session presented at BioMedEng18, London, United Kingdom.

Research output: Contribution to conferencePoster

TY - CONF

T1 - Wavelet analysis in the diagnosis of knee instability

T2 - early results from a novel assessment method

AU - Wallace, D.T.

AU - Clarke, J.V.

AU - Riches, P.E.

PY - 2018/9/6

Y1 - 2018/9/6

N2 - Introduction: Instability in the knee following total knee arthroplasty (TKA) is a leading cause for dissatisfaction, often requiring revision surgery1. However, instability remains a symptom with no corresponding objective measure. The purpose of this study was to identify quantifiable differences in frontal plane accelerations at the knee between subjectively “stable” and “unstable” TKA patients. Methods: Post-operative TKA patients with symptomatic instability were recruited from a national orthopaedic centre, along with asymptomatic post-operative TKA patients, and healthy controls. Frontal plane knee accelerations were measured using an accelerometer mounted on the lateral aspect of the proximal lower leg. Individual strides were extracted, and continuous wavelet transform (CWT) of the accelerations were performed, with the absolute value of the CWT coefficient examined for differences between groups. Results & Discussion: 10 controls, 9 “stable”, and 7 “unstable” participants were tested. Increased CWT coefficients were found between 50% and 80% of stride (heel strike to heel strike), and between 4 and 8Hz, in the “unstable” TKA group in comparison with the “stable” and control groups. This corresponds to increased oscillation at the proximal tibia frontal plane during early swing phase, consistent with reduced stiffness and increased contact point movement in subjectively unstable osteoarthritic knees2,3. Conclusion: Accelerations in the frontal plane of the knee during swing phase corresponds to subjective instability in the TKA. This portable and inexpensive technology has potential for use in clinics to quantify instability in the unhappy TKA.

AB - Introduction: Instability in the knee following total knee arthroplasty (TKA) is a leading cause for dissatisfaction, often requiring revision surgery1. However, instability remains a symptom with no corresponding objective measure. The purpose of this study was to identify quantifiable differences in frontal plane accelerations at the knee between subjectively “stable” and “unstable” TKA patients. Methods: Post-operative TKA patients with symptomatic instability were recruited from a national orthopaedic centre, along with asymptomatic post-operative TKA patients, and healthy controls. Frontal plane knee accelerations were measured using an accelerometer mounted on the lateral aspect of the proximal lower leg. Individual strides were extracted, and continuous wavelet transform (CWT) of the accelerations were performed, with the absolute value of the CWT coefficient examined for differences between groups. Results & Discussion: 10 controls, 9 “stable”, and 7 “unstable” participants were tested. Increased CWT coefficients were found between 50% and 80% of stride (heel strike to heel strike), and between 4 and 8Hz, in the “unstable” TKA group in comparison with the “stable” and control groups. This corresponds to increased oscillation at the proximal tibia frontal plane during early swing phase, consistent with reduced stiffness and increased contact point movement in subjectively unstable osteoarthritic knees2,3. Conclusion: Accelerations in the frontal plane of the knee during swing phase corresponds to subjective instability in the TKA. This portable and inexpensive technology has potential for use in clinics to quantify instability in the unhappy TKA.

KW - wavelet analysis

KW - knee instability

KW - total knee arthroplasty

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Wallace DT, Clarke JV, Riches PE. Wavelet analysis in the diagnosis of knee instability: early results from a novel assessment method. 2018. Poster session presented at BioMedEng18, London, United Kingdom.