Developing an analogue residual limb for comparative DVC analysis of transtibial prosthetic socket designs
Developing an analogue residual limb for comparative DVC analysis of transtibial prosthetic socket designs
Personalised prosthetic sockets are fabricated by expert clinicians in a skill- and experience-based process, with research providing tools to support evidence-based practice. We propose that digital volume correlation (DVC) may offer a deeper understanding of load transfer from prosthetic sockets into the residual limb, and tissue injury risk. This study’s aim was to develop a transtibial amputated limb analogue for volumetric strain estimation using DVC, evaluating its ability to distinguish between socket designs. A soft tissue analogue material was developed, comprising silicone elastomer and sand particles as fiducial markers for image correlation. The material was cast to form an analogue residual limb informed by an MRI scan of a person with transtibial amputation, for whom two polymer check sockets were produced by an expert prosthetist. The model was micro-CT scanned according to (i) an unloaded noise study protocol and (ii) a case study comparison between the two socket designs, loaded to represent two-legged stance. The scans were reconstructed to give 108 µm voxels. The DVC noise study indicated a 64 vx subvolume and 50% overlap, giving better than 0.32% strain sensitivity, and ~3.5 mm spatial resolution of strain. Strain fields induced by the loaded sockets indicated tensile, compressive and shear strain magnitudes in the order of 10%, with a high signal:noise ratio enabling distinction between the two socket designs. DVC may not be applicable for socket design in the clinical setting, but does offer critical 3D strain information from which existing in vitro and in silico tools can be compared and validated to support the design and manufacture of prosthetic sockets, and enhance the biomechanical understanding of the load transfer between the limb and the prosthesis.
Amputation, DVC, Digital volume correlation, Micro-CT, Prosthetic
1-15
Rankin, Kathryn
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Steer, Joshua
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Paton, Joshua
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Mavrogordato, Mark
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Marter, Alexander
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Worsley, Peter
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Browne, Martin
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Dickinson, Alexander
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7 September 2020
Rankin, Kathryn
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Steer, Joshua
b958f526-9782-4e36-9c49-ad48e8f650ed
Paton, Joshua
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Mavrogordato, Mark
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Marter, Alexander
58759fea-80f7-4c31-b76f-36da5e5ae9fd
Worsley, Peter
6d33aee3-ef43-468d-aef6-86d190de6756
Browne, Martin
6578cc37-7bd6-43b9-ae5c-77ccb7726397
Dickinson, Alexander
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Rankin, Kathryn, Steer, Joshua, Paton, Joshua, Mavrogordato, Mark, Marter, Alexander, Worsley, Peter, Browne, Martin and Dickinson, Alexander
(2020)
Developing an analogue residual limb for comparative DVC analysis of transtibial prosthetic socket designs.
Materials, 13 (18), , [3955].
(doi:10.3390/ma13183955).
Abstract
Personalised prosthetic sockets are fabricated by expert clinicians in a skill- and experience-based process, with research providing tools to support evidence-based practice. We propose that digital volume correlation (DVC) may offer a deeper understanding of load transfer from prosthetic sockets into the residual limb, and tissue injury risk. This study’s aim was to develop a transtibial amputated limb analogue for volumetric strain estimation using DVC, evaluating its ability to distinguish between socket designs. A soft tissue analogue material was developed, comprising silicone elastomer and sand particles as fiducial markers for image correlation. The material was cast to form an analogue residual limb informed by an MRI scan of a person with transtibial amputation, for whom two polymer check sockets were produced by an expert prosthetist. The model was micro-CT scanned according to (i) an unloaded noise study protocol and (ii) a case study comparison between the two socket designs, loaded to represent two-legged stance. The scans were reconstructed to give 108 µm voxels. The DVC noise study indicated a 64 vx subvolume and 50% overlap, giving better than 0.32% strain sensitivity, and ~3.5 mm spatial resolution of strain. Strain fields induced by the loaded sockets indicated tensile, compressive and shear strain magnitudes in the order of 10%, with a high signal:noise ratio enabling distinction between the two socket designs. DVC may not be applicable for socket design in the clinical setting, but does offer critical 3D strain information from which existing in vitro and in silico tools can be compared and validated to support the design and manufacture of prosthetic sockets, and enhance the biomechanical understanding of the load transfer between the limb and the prosthesis.
Text
materials-13-03955
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More information
In preparation date: 12 June 2020
Submitted date: 31 July 2020
Accepted/In Press date: 2 September 2020
e-pub ahead of print date: 7 September 2020
Published date: 7 September 2020
Additional Information:
Funding Information:
Funding: This research was funded by the Royal Academy of Engineering, grant number RF/130, and the Engineering and Physical Sciences Research Council (EPSRC), grant numbers grants EP/M508147/1 and EP/N02723X/1.
Funding Information:
Acknowledgments: We are grateful to Herbert Ganter and Florian Blab for providing sockets and participant data from EUROSTARS project 9396, under study ethics protocols 2016_BLM_0009 (D) and ERGO 29927 (UK). We also thank the µ-VIS X-Ray Imaging Centre at the University of Southampton for provision of tomographic imaging facilities, supported by EPSRC grant EP-H01506X.
Publisher Copyright:
© 2020 by the authors.
Keywords:
Amputation, DVC, Digital volume correlation, Micro-CT, Prosthetic
Identifiers
Local EPrints ID: 443642
URI: http://eprints.soton.ac.uk/id/eprint/443642
PURE UUID: d05c015d-c2d1-4334-8600-20dafd9eed1d
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Date deposited: 07 Sep 2020 16:30
Last modified: 06 Jun 2024 02:05
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Author:
Kathryn Rankin
Author:
Joshua Paton
Author:
Alexander Marter
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