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Evaluating socket interface pressure and shear for a trans-femoral amputee with synchronised gait event detection

Evaluating socket interface pressure and shear for a trans-femoral amputee with synchronised gait event detection
Evaluating socket interface pressure and shear for a trans-femoral amputee with synchronised gait event detection
Introduction interface loading characteristics between the lower limb residuum and prosthetic socket is critical for tissue health, walking stability and overall rehabilitation outcomes. Dynamic interface pressure and shear have been reported to show complex biomechanical coupling [1]. Load characteristics at different residuum locations are expected to vary during gait. However, so far, there are few reports on synchronised measurement between gait events and interface loading to help understand load transfer mechanisms. A wearable stress sensing system and inertial measurement unit (IMU) were used capture interface loading profiles and synchronised gait events, respectively, on a trans-femoral (TF) amputee.

Methods: a left-sided TF amputee participated (weight 56 kg, ischial containment socket). An IMU was mounted distal to the prosthetic knee pivot (Fig 1a) and tri-axial pressure and shear sensors [2] were placed on the inner socket at known load-bearing regions (Fig 1b), i.e., posterior-distal (PD), posterior-proximal (PP) and anterior-proximal (AP) to measure pressure (P), circumferential (SC) and longitudinal shear (SL). The participant walked at self-selected speed along a level-surfaced corridor. IMU and sensor data outputs were synchronised.

Results and Discussion: Fig 2. shows typical angular velocity (AV) and P measured at PD. AV was used to identify timing of key gait events [3] including initial contact (IC), mid-stance (MST), toe-off (TO) and mid-swing (MSW) based on which interface P, SC and SL were obtained at different sites (Fig 3a-d). At IC (Fig 3a), P at PP (18±2kPa) was higher than that at AP (6±2kPa) as the residuum pushes against the PP location of the socket wall [1]. In MST and TO, P were relatively well-distributed (P of 27-34kPa and 20-25kPa, respectively). In MSW, significant reduction of P was obtained at AP (3±1kPa) accompanied by higher SL (8±1kPa) compared to other sites, indicating the residuum moving up in the socket.

Conclusion: this is a first-of-its-kind results linking gait events with interface pressure and shear data for lower limb amputees, which enables the study of load transfer mechanism. Detailed studies will be presented to analyse real-world kinetic and kinematic analysis while conducting activities of daily living.

Acknowledgments
This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) grant EP/S02249X/1 for the Centre for Doctoral Training in Prosthetics and Orthotics.

References
[1] J. Tang et al., Med Eng Phys, 2017; 49:131-139.
[2] P. Laszczak et al., Med Eng Phys, 2016; 38(7):695-700.
[3] Z. Aftab & R. Shad, PLOS ONE, 2022; 17(5): e0266726
Devin, Kirstie
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Tang, Jinghua
b4b9a22c-fd6d-427a-9ab1-51184c1d2a2c
Moser, David
09874cab-348f-47f9-b018-1c2875d16998
Jiang, Liudi
374f2414-51f0-418f-a316-e7db0d6dc4d1
Devin, Kirstie
a8f23fa0-db53-44a4-abd8-03a72800f88d
Tang, Jinghua
b4b9a22c-fd6d-427a-9ab1-51184c1d2a2c
Moser, David
09874cab-348f-47f9-b018-1c2875d16998
Jiang, Liudi
374f2414-51f0-418f-a316-e7db0d6dc4d1

Devin, Kirstie, Tang, Jinghua, Moser, David and Jiang, Liudi (2023) Evaluating socket interface pressure and shear for a trans-femoral amputee with synchronised gait event detection. BioMedEng23, Swansea University, Swansea, United Kingdom. 14 - 15 Sep 2023. (In Press)

Record type: Conference or Workshop Item (Poster)

Abstract

Introduction interface loading characteristics between the lower limb residuum and prosthetic socket is critical for tissue health, walking stability and overall rehabilitation outcomes. Dynamic interface pressure and shear have been reported to show complex biomechanical coupling [1]. Load characteristics at different residuum locations are expected to vary during gait. However, so far, there are few reports on synchronised measurement between gait events and interface loading to help understand load transfer mechanisms. A wearable stress sensing system and inertial measurement unit (IMU) were used capture interface loading profiles and synchronised gait events, respectively, on a trans-femoral (TF) amputee.

Methods: a left-sided TF amputee participated (weight 56 kg, ischial containment socket). An IMU was mounted distal to the prosthetic knee pivot (Fig 1a) and tri-axial pressure and shear sensors [2] were placed on the inner socket at known load-bearing regions (Fig 1b), i.e., posterior-distal (PD), posterior-proximal (PP) and anterior-proximal (AP) to measure pressure (P), circumferential (SC) and longitudinal shear (SL). The participant walked at self-selected speed along a level-surfaced corridor. IMU and sensor data outputs were synchronised.

Results and Discussion: Fig 2. shows typical angular velocity (AV) and P measured at PD. AV was used to identify timing of key gait events [3] including initial contact (IC), mid-stance (MST), toe-off (TO) and mid-swing (MSW) based on which interface P, SC and SL were obtained at different sites (Fig 3a-d). At IC (Fig 3a), P at PP (18±2kPa) was higher than that at AP (6±2kPa) as the residuum pushes against the PP location of the socket wall [1]. In MST and TO, P were relatively well-distributed (P of 27-34kPa and 20-25kPa, respectively). In MSW, significant reduction of P was obtained at AP (3±1kPa) accompanied by higher SL (8±1kPa) compared to other sites, indicating the residuum moving up in the socket.

Conclusion: this is a first-of-its-kind results linking gait events with interface pressure and shear data for lower limb amputees, which enables the study of load transfer mechanism. Detailed studies will be presented to analyse real-world kinetic and kinematic analysis while conducting activities of daily living.

Acknowledgments
This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) grant EP/S02249X/1 for the Centre for Doctoral Training in Prosthetics and Orthotics.

References
[1] J. Tang et al., Med Eng Phys, 2017; 49:131-139.
[2] P. Laszczak et al., Med Eng Phys, 2016; 38(7):695-700.
[3] Z. Aftab & R. Shad, PLOS ONE, 2022; 17(5): e0266726

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Accepted/In Press date: 2023
Venue - Dates: BioMedEng23, Swansea University, Swansea, United Kingdom, 2023-09-14 - 2023-09-15

Identifiers

Local EPrints ID: 477645
URI: http://eprints.soton.ac.uk/id/eprint/477645
PURE UUID: 70b6afe4-33b9-437b-bc10-eb34c6fbd394
ORCID for Kirstie Devin: ORCID iD orcid.org/0000-0001-6794-2375
ORCID for Jinghua Tang: ORCID iD orcid.org/0000-0003-3359-5891
ORCID for Liudi Jiang: ORCID iD orcid.org/0000-0002-3400-825X

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Date deposited: 12 Jun 2023 16:39
Last modified: 13 Jul 2024 02:12

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Contributors

Author: Kirstie Devin ORCID iD
Author: Jinghua Tang ORCID iD
Author: David Moser
Author: Liudi Jiang ORCID iD

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