TPress
1.
Trinler, U.; Heitzmann, D. W. W.; Hitzeroth, S.; Alimusaj, M.; Rehg, M.; Hogan, A.
In: Prosthet. Orthot. Int., Bd. 47, Nr. 1, S. 94–100, 2023, ISSN: 0309-3646.
Abstract | Links | Schlagwörter: adult, amputation, article, biomechanics, carbon fiber, clinical article, cohort analysis, ComfyStep, female, foot prosthesis, ground reaction force, human, kinematics, kinetics, knee function, L.A.S.A.R. Posture device, male, medical device, post hoc analysis, prospective study, range of motion, statistical analysis, three dimensional printing, transtibial amputation
@article{Trinler2023,
title = {Biomechanical comparison of a 3D-printed prosthetic foot with conventional feet in people with transtibial amputation: A prospective cohort study},
author = {U. Trinler and D. W. W. Heitzmann and S. Hitzeroth and M. Alimusaj and M. Rehg and A. Hogan},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2022874959&from=export},
doi = {10.1097/PXR.0000000000000180},
issn = {0309-3646},
year = {2023},
date = {2023-08-01},
journal = {Prosthet. Orthot. Int.},
volume = {47},
number = {1},
pages = {94–100},
publisher = {Ovid Technologies (Wolters Kluwer Health)},
address = {U. Trinler, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, Ludwigshafen, Germany},
abstract = {Introduction: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. Methods: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. Results: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. Conclusion: In principle, 3D-printed feet have advantages over conventional “off the shelf” feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.},
keywords = {adult, amputation, article, biomechanics, carbon fiber, clinical article, cohort analysis, ComfyStep, female, foot prosthesis, ground reaction force, human, kinematics, kinetics, knee function, L.A.S.A.R. Posture device, male, medical device, post hoc analysis, prospective study, range of motion, statistical analysis, three dimensional printing, transtibial amputation},
pubstate = {published},
tppubtype = {article}
}
Introduction: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. Methods: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. Results: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. Conclusion: In principle, 3D-printed feet have advantages over conventional “off the shelf” feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.
2.
Manz, Sabina; Seifert, Dirk; Altenburg, Bjoern; Schmalz, Thomas; Dosen, Strahinja; Gonzalez-Vargas, Jose
In: Clinical Biomechanics, Bd. 106, S. 105988, 2023, ISSN: 0268-0033.
Abstract | Links | Schlagwörter: above knee prosthesis, adult, article, C-leg, Challenger, clinical article, controlled study, data analysis software, degree of freedom, endoprosthesis, feasibility study, foot prosthesis, gait, gait analysis system, gait deviation index, Genium X3, Germany, gold standard, human, kinematics, kinetics, knee angle, knee function, knee prosthesis, leg amputation, male, microprocessor, middle aged, motion analysis system, motion sensor, SPSS, strain gauge transducer, Taleo, thigh, Triton, tyloxapol, walk test, walking speed
@article{Manz2023,
title = {Using embedded prosthesis sensors for clinical gait analyses in people with lower limb amputation: A feasibility study},
author = {Sabina Manz and Dirk Seifert and Bjoern Altenburg and Thomas Schmalz and Strahinja Dosen and Jose Gonzalez-Vargas},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2024655048&from=export},
doi = {10.1016/j.clinbiomech.2023.105988},
issn = {0268-0033},
year = {2023},
date = {2023-06-01},
journal = {Clinical Biomechanics},
volume = {106},
pages = {105988},
publisher = {Elsevier BV},
address = {J. Gonzalez-Vargas, Ottobock SE & Co. KGaA, Duderstadt, Germany},
abstract = {Background: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint. Methods: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors. Findings: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh). Interpretation: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.},
keywords = {above knee prosthesis, adult, article, C-leg, Challenger, clinical article, controlled study, data analysis software, degree of freedom, endoprosthesis, feasibility study, foot prosthesis, gait, gait analysis system, gait deviation index, Genium X3, Germany, gold standard, human, kinematics, kinetics, knee angle, knee function, knee prosthesis, leg amputation, male, microprocessor, middle aged, motion analysis system, motion sensor, SPSS, strain gauge transducer, Taleo, thigh, Triton, tyloxapol, walk test, walking speed},
pubstate = {published},
tppubtype = {article}
}
Background: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint. Methods: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors. Findings: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh). Interpretation: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.
3.
Ernst, M.; Altenburg, B.; Schmalz, T.; Kannenberg, A.; Bellmann, M.
Benefits of a microprocessor-controlled prosthetic foot for ascending and descending slopes Artikel
In: J. NeuroEng. Rehabil., Bd. 19, Nr. 1, 2022, ISSN: 1743-0003.
Abstract | Links | Schlagwörter: adult, aged, article, biomechanics, clinical article, controlled study, effect size, foot prosthesis, human, kinematics, knee function, leg amputation, microprocessor, middle aged, motion analysis system, patient participation, range of motion, slope factor, transfemoral amputation, transtibial amputation, walking
@article{Ernst2022,
title = {Benefits of a microprocessor-controlled prosthetic foot for ascending and descending slopes},
author = {M. Ernst and B. Altenburg and T. Schmalz and A. Kannenberg and M. Bellmann},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2014862458&from=export},
doi = {10.1186/s12984-022-00983-y},
issn = {1743-0003},
year = {2022},
date = {2022-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {19},
number = {1},
address = {M. Ernst, Research Biomechanics, CR&S, Ottobock SE & Co. KGaA, Göttingen, Germany},
abstract = {Background: Prosthetic feet are prescribed for persons with a lower-limb amputation to restore lost mobility. However, due to limited adaptability of their ankles and springs, situations like walking on slopes or uneven ground remain challenging. This study investigated to what extent a microprocessor-controlled prosthetic foot (MPF) facilitates walking on slopes. Methods: Seven persons each with a unilateral transtibial amputation (TTA) and unilateral transfemoral amputation (TFA) as well as ten able-bodied subjects participated. Participants were studied while using a MPF and their prescribed standard feet with fixed ankle attachments. The study investigated ascending and descending a 10° slope. Kinematic and kinetic data were recorded with a motion capture system. Biomechanical parameters, in particular leg joint angles, shank orientation and external joint moments of the prosthetics side were calculated. Results: Prosthetic feet- and subject group-dependent joint angle and moment characteristics were observed for both situations. The MPF showed a larger and situation-dependent ankle range of motion compared to the standard feet. Furthermore, it remained in a dorsiflexed position during swing. While ascending, the MPF adapted the dorsiflexion moment and reduced the knee extension moment. At vertical shank orientation, it reduced the knee extension moment by 26% for TFA and 49% for TTA compared to the standard feet. For descending, differences between feet in the biomechanical knee characteristics were found for the TTA group, but not for the TFA group. At the vertical shank angle during slope descent, TTA demonstrated a behavior of the ankle moment similar to able-bodied controls when using the MPF. Conclusions: The studied MPF facilitated walking on slopes by adapting instantaneously to inclinations and, thus, easing the forward rotation of the leg over the prosthetic foot compared to standard feet with a fixed ankle attachment with amputation-level dependent effect sizes. It assumed a dorsiflexed ankle angle during swing, enabled a larger ankle range of motion and reduced the moments acting on the residual knee of TTA compared to the prescribed prosthetic standard feet. For individuals with TFA, the prosthetic knee joint seems to play a more crucial role for walking on ramps than the foot.},
keywords = {adult, aged, article, biomechanics, clinical article, controlled study, effect size, foot prosthesis, human, kinematics, knee function, leg amputation, microprocessor, middle aged, motion analysis system, patient participation, range of motion, slope factor, transfemoral amputation, transtibial amputation, walking},
pubstate = {published},
tppubtype = {article}
}
Background: Prosthetic feet are prescribed for persons with a lower-limb amputation to restore lost mobility. However, due to limited adaptability of their ankles and springs, situations like walking on slopes or uneven ground remain challenging. This study investigated to what extent a microprocessor-controlled prosthetic foot (MPF) facilitates walking on slopes. Methods: Seven persons each with a unilateral transtibial amputation (TTA) and unilateral transfemoral amputation (TFA) as well as ten able-bodied subjects participated. Participants were studied while using a MPF and their prescribed standard feet with fixed ankle attachments. The study investigated ascending and descending a 10° slope. Kinematic and kinetic data were recorded with a motion capture system. Biomechanical parameters, in particular leg joint angles, shank orientation and external joint moments of the prosthetics side were calculated. Results: Prosthetic feet- and subject group-dependent joint angle and moment characteristics were observed for both situations. The MPF showed a larger and situation-dependent ankle range of motion compared to the standard feet. Furthermore, it remained in a dorsiflexed position during swing. While ascending, the MPF adapted the dorsiflexion moment and reduced the knee extension moment. At vertical shank orientation, it reduced the knee extension moment by 26% for TFA and 49% for TTA compared to the standard feet. For descending, differences between feet in the biomechanical knee characteristics were found for the TTA group, but not for the TFA group. At the vertical shank angle during slope descent, TTA demonstrated a behavior of the ankle moment similar to able-bodied controls when using the MPF. Conclusions: The studied MPF facilitated walking on slopes by adapting instantaneously to inclinations and, thus, easing the forward rotation of the leg over the prosthetic foot compared to standard feet with a fixed ankle attachment with amputation-level dependent effect sizes. It assumed a dorsiflexed ankle angle during swing, enabled a larger ankle range of motion and reduced the moments acting on the residual knee of TTA compared to the prescribed prosthetic standard feet. For individuals with TFA, the prosthetic knee joint seems to play a more crucial role for walking on ramps than the foot.
4.
Pröbsting, E.; Altenburg, B.; Bellmann, M.; Krug, K.; Schmalz, T.
In: Prosthet. Orthot. Int., Bd. 46, Nr. 4, S. 306–313, 2022, ISSN: 0309-3646.
Abstract | Links | Schlagwörter: adduction, adult, amputation, ankle, article, C Leg 4, camera, carbon fiber, clinical article, foot prosthesis, forefoot, human, knee, knee function, lower limb, male, microprocessor, retrospective study, sensor, walking, walking speed
@article{Proebsting2022,
title = {How does ankle power on the prosthetic side influence loading parameters on the sound side during level walking of persons with transfemoral amputation?},
author = {E. Pröbsting and B. Altenburg and M. Bellmann and K. Krug and T. Schmalz},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2019708323&from=export},
doi = {10.1097/pxr.0000000000000099},
issn = {0309-3646},
year = {2022},
date = {2022-01-01},
journal = {Prosthet. Orthot. Int.},
volume = {46},
number = {4},
pages = {306–313},
address = {E. Pröbsting, Ottobock SE & Co. KGaA, Herrmann-Rein-Straße 2a, Göttingen, Germany},
abstract = {Background:Increased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side.Objective:To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters.Study design:Interventional cross sectional study.Methods:Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used.Results:The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity.Conclusions:The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees.},
keywords = {adduction, adult, amputation, ankle, article, C Leg 4, camera, carbon fiber, clinical article, foot prosthesis, forefoot, human, knee, knee function, lower limb, male, microprocessor, retrospective study, sensor, walking, walking speed},
pubstate = {published},
tppubtype = {article}
}
Background:Increased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side.Objective:To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters.Study design:Interventional cross sectional study.Methods:Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used.Results:The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity.Conclusions:The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees.
5.
Yazdani, M.; Hajiaghaei, B.; Saeedi, H.; Kamali, M.; Yousefi, M.
In: Curr. Orthop. Pract., Bd. 32, Nr. 5, S. 505–511, 2021, ISSN: 1940-7041.
Abstract | Links | Schlagwörter: adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test
@article{Yazdani2021,
title = {Does the socket design affect symmetry and spatiotemporal gait parameters? A case series of two transfemoral amputees},
author = {M. Yazdani and B. Hajiaghaei and H. Saeedi and M. Kamali and M. Yousefi},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L635549609&from=export},
doi = {10.1097/bco.0000000000001022},
issn = {1940-7041},
year = {2021},
date = {2021-01-01},
journal = {Curr. Orthop. Pract.},
volume = {32},
number = {5},
pages = {505–511},
address = {B. Hajiaghaei, Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Nezam Ave, Tehran, Iran},
abstract = {Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.},
keywords = {adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test},
pubstate = {published},
tppubtype = {article}
}
Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.
2023
Trinler, U.; Heitzmann, D. W. W.; Hitzeroth, S.; Alimusaj, M.; Rehg, M.; Hogan, A.
In: Prosthet. Orthot. Int., Bd. 47, Nr. 1, S. 94–100, 2023, ISSN: 0309-3646.
Abstract | Links | Schlagwörter: adult, amputation, article, biomechanics, carbon fiber, clinical article, cohort analysis, ComfyStep, female, foot prosthesis, ground reaction force, human, kinematics, kinetics, knee function, L.A.S.A.R. Posture device, male, medical device, post hoc analysis, prospective study, range of motion, statistical analysis, three dimensional printing, transtibial amputation
@article{Trinler2023,
title = {Biomechanical comparison of a 3D-printed prosthetic foot with conventional feet in people with transtibial amputation: A prospective cohort study},
author = {U. Trinler and D. W. W. Heitzmann and S. Hitzeroth and M. Alimusaj and M. Rehg and A. Hogan},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2022874959&from=export},
doi = {10.1097/PXR.0000000000000180},
issn = {0309-3646},
year = {2023},
date = {2023-08-01},
journal = {Prosthet. Orthot. Int.},
volume = {47},
number = {1},
pages = {94–100},
publisher = {Ovid Technologies (Wolters Kluwer Health)},
address = {U. Trinler, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, Ludwigshafen, Germany},
abstract = {Introduction: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. Methods: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. Results: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. Conclusion: In principle, 3D-printed feet have advantages over conventional “off the shelf” feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.},
keywords = {adult, amputation, article, biomechanics, carbon fiber, clinical article, cohort analysis, ComfyStep, female, foot prosthesis, ground reaction force, human, kinematics, kinetics, knee function, L.A.S.A.R. Posture device, male, medical device, post hoc analysis, prospective study, range of motion, statistical analysis, three dimensional printing, transtibial amputation},
pubstate = {published},
tppubtype = {article}
}
Introduction: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. Methods: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. Results: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. Conclusion: In principle, 3D-printed feet have advantages over conventional “off the shelf” feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.
Manz, Sabina; Seifert, Dirk; Altenburg, Bjoern; Schmalz, Thomas; Dosen, Strahinja; Gonzalez-Vargas, Jose
In: Clinical Biomechanics, Bd. 106, S. 105988, 2023, ISSN: 0268-0033.
Abstract | Links | Schlagwörter: above knee prosthesis, adult, article, C-leg, Challenger, clinical article, controlled study, data analysis software, degree of freedom, endoprosthesis, feasibility study, foot prosthesis, gait, gait analysis system, gait deviation index, Genium X3, Germany, gold standard, human, kinematics, kinetics, knee angle, knee function, knee prosthesis, leg amputation, male, microprocessor, middle aged, motion analysis system, motion sensor, SPSS, strain gauge transducer, Taleo, thigh, Triton, tyloxapol, walk test, walking speed
@article{Manz2023,
title = {Using embedded prosthesis sensors for clinical gait analyses in people with lower limb amputation: A feasibility study},
author = {Sabina Manz and Dirk Seifert and Bjoern Altenburg and Thomas Schmalz and Strahinja Dosen and Jose Gonzalez-Vargas},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2024655048&from=export},
doi = {10.1016/j.clinbiomech.2023.105988},
issn = {0268-0033},
year = {2023},
date = {2023-06-01},
journal = {Clinical Biomechanics},
volume = {106},
pages = {105988},
publisher = {Elsevier BV},
address = {J. Gonzalez-Vargas, Ottobock SE & Co. KGaA, Duderstadt, Germany},
abstract = {Background: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint. Methods: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors. Findings: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh). Interpretation: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.},
keywords = {above knee prosthesis, adult, article, C-leg, Challenger, clinical article, controlled study, data analysis software, degree of freedom, endoprosthesis, feasibility study, foot prosthesis, gait, gait analysis system, gait deviation index, Genium X3, Germany, gold standard, human, kinematics, kinetics, knee angle, knee function, knee prosthesis, leg amputation, male, microprocessor, middle aged, motion analysis system, motion sensor, SPSS, strain gauge transducer, Taleo, thigh, Triton, tyloxapol, walk test, walking speed},
pubstate = {published},
tppubtype = {article}
}
Background: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint. Methods: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors. Findings: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh). Interpretation: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.
2022
Ernst, M.; Altenburg, B.; Schmalz, T.; Kannenberg, A.; Bellmann, M.
Benefits of a microprocessor-controlled prosthetic foot for ascending and descending slopes Artikel
In: J. NeuroEng. Rehabil., Bd. 19, Nr. 1, 2022, ISSN: 1743-0003.
Abstract | Links | Schlagwörter: adult, aged, article, biomechanics, clinical article, controlled study, effect size, foot prosthesis, human, kinematics, knee function, leg amputation, microprocessor, middle aged, motion analysis system, patient participation, range of motion, slope factor, transfemoral amputation, transtibial amputation, walking
@article{Ernst2022,
title = {Benefits of a microprocessor-controlled prosthetic foot for ascending and descending slopes},
author = {M. Ernst and B. Altenburg and T. Schmalz and A. Kannenberg and M. Bellmann},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2014862458&from=export},
doi = {10.1186/s12984-022-00983-y},
issn = {1743-0003},
year = {2022},
date = {2022-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {19},
number = {1},
address = {M. Ernst, Research Biomechanics, CR&S, Ottobock SE & Co. KGaA, Göttingen, Germany},
abstract = {Background: Prosthetic feet are prescribed for persons with a lower-limb amputation to restore lost mobility. However, due to limited adaptability of their ankles and springs, situations like walking on slopes or uneven ground remain challenging. This study investigated to what extent a microprocessor-controlled prosthetic foot (MPF) facilitates walking on slopes. Methods: Seven persons each with a unilateral transtibial amputation (TTA) and unilateral transfemoral amputation (TFA) as well as ten able-bodied subjects participated. Participants were studied while using a MPF and their prescribed standard feet with fixed ankle attachments. The study investigated ascending and descending a 10° slope. Kinematic and kinetic data were recorded with a motion capture system. Biomechanical parameters, in particular leg joint angles, shank orientation and external joint moments of the prosthetics side were calculated. Results: Prosthetic feet- and subject group-dependent joint angle and moment characteristics were observed for both situations. The MPF showed a larger and situation-dependent ankle range of motion compared to the standard feet. Furthermore, it remained in a dorsiflexed position during swing. While ascending, the MPF adapted the dorsiflexion moment and reduced the knee extension moment. At vertical shank orientation, it reduced the knee extension moment by 26% for TFA and 49% for TTA compared to the standard feet. For descending, differences between feet in the biomechanical knee characteristics were found for the TTA group, but not for the TFA group. At the vertical shank angle during slope descent, TTA demonstrated a behavior of the ankle moment similar to able-bodied controls when using the MPF. Conclusions: The studied MPF facilitated walking on slopes by adapting instantaneously to inclinations and, thus, easing the forward rotation of the leg over the prosthetic foot compared to standard feet with a fixed ankle attachment with amputation-level dependent effect sizes. It assumed a dorsiflexed ankle angle during swing, enabled a larger ankle range of motion and reduced the moments acting on the residual knee of TTA compared to the prescribed prosthetic standard feet. For individuals with TFA, the prosthetic knee joint seems to play a more crucial role for walking on ramps than the foot.},
keywords = {adult, aged, article, biomechanics, clinical article, controlled study, effect size, foot prosthesis, human, kinematics, knee function, leg amputation, microprocessor, middle aged, motion analysis system, patient participation, range of motion, slope factor, transfemoral amputation, transtibial amputation, walking},
pubstate = {published},
tppubtype = {article}
}
Background: Prosthetic feet are prescribed for persons with a lower-limb amputation to restore lost mobility. However, due to limited adaptability of their ankles and springs, situations like walking on slopes or uneven ground remain challenging. This study investigated to what extent a microprocessor-controlled prosthetic foot (MPF) facilitates walking on slopes. Methods: Seven persons each with a unilateral transtibial amputation (TTA) and unilateral transfemoral amputation (TFA) as well as ten able-bodied subjects participated. Participants were studied while using a MPF and their prescribed standard feet with fixed ankle attachments. The study investigated ascending and descending a 10° slope. Kinematic and kinetic data were recorded with a motion capture system. Biomechanical parameters, in particular leg joint angles, shank orientation and external joint moments of the prosthetics side were calculated. Results: Prosthetic feet- and subject group-dependent joint angle and moment characteristics were observed for both situations. The MPF showed a larger and situation-dependent ankle range of motion compared to the standard feet. Furthermore, it remained in a dorsiflexed position during swing. While ascending, the MPF adapted the dorsiflexion moment and reduced the knee extension moment. At vertical shank orientation, it reduced the knee extension moment by 26% for TFA and 49% for TTA compared to the standard feet. For descending, differences between feet in the biomechanical knee characteristics were found for the TTA group, but not for the TFA group. At the vertical shank angle during slope descent, TTA demonstrated a behavior of the ankle moment similar to able-bodied controls when using the MPF. Conclusions: The studied MPF facilitated walking on slopes by adapting instantaneously to inclinations and, thus, easing the forward rotation of the leg over the prosthetic foot compared to standard feet with a fixed ankle attachment with amputation-level dependent effect sizes. It assumed a dorsiflexed ankle angle during swing, enabled a larger ankle range of motion and reduced the moments acting on the residual knee of TTA compared to the prescribed prosthetic standard feet. For individuals with TFA, the prosthetic knee joint seems to play a more crucial role for walking on ramps than the foot.
Pröbsting, E.; Altenburg, B.; Bellmann, M.; Krug, K.; Schmalz, T.
In: Prosthet. Orthot. Int., Bd. 46, Nr. 4, S. 306–313, 2022, ISSN: 0309-3646.
Abstract | Links | Schlagwörter: adduction, adult, amputation, ankle, article, C Leg 4, camera, carbon fiber, clinical article, foot prosthesis, forefoot, human, knee, knee function, lower limb, male, microprocessor, retrospective study, sensor, walking, walking speed
@article{Proebsting2022,
title = {How does ankle power on the prosthetic side influence loading parameters on the sound side during level walking of persons with transfemoral amputation?},
author = {E. Pröbsting and B. Altenburg and M. Bellmann and K. Krug and T. Schmalz},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2019708323&from=export},
doi = {10.1097/pxr.0000000000000099},
issn = {0309-3646},
year = {2022},
date = {2022-01-01},
journal = {Prosthet. Orthot. Int.},
volume = {46},
number = {4},
pages = {306–313},
address = {E. Pröbsting, Ottobock SE & Co. KGaA, Herrmann-Rein-Straße 2a, Göttingen, Germany},
abstract = {Background:Increased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side.Objective:To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters.Study design:Interventional cross sectional study.Methods:Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used.Results:The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity.Conclusions:The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees.},
keywords = {adduction, adult, amputation, ankle, article, C Leg 4, camera, carbon fiber, clinical article, foot prosthesis, forefoot, human, knee, knee function, lower limb, male, microprocessor, retrospective study, sensor, walking, walking speed},
pubstate = {published},
tppubtype = {article}
}
Background:Increased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side.Objective:To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters.Study design:Interventional cross sectional study.Methods:Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used.Results:The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity.Conclusions:The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees.
2021
Yazdani, M.; Hajiaghaei, B.; Saeedi, H.; Kamali, M.; Yousefi, M.
In: Curr. Orthop. Pract., Bd. 32, Nr. 5, S. 505–511, 2021, ISSN: 1940-7041.
Abstract | Links | Schlagwörter: adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test
@article{Yazdani2021,
title = {Does the socket design affect symmetry and spatiotemporal gait parameters? A case series of two transfemoral amputees},
author = {M. Yazdani and B. Hajiaghaei and H. Saeedi and M. Kamali and M. Yousefi},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L635549609&from=export},
doi = {10.1097/bco.0000000000001022},
issn = {1940-7041},
year = {2021},
date = {2021-01-01},
journal = {Curr. Orthop. Pract.},
volume = {32},
number = {5},
pages = {505–511},
address = {B. Hajiaghaei, Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Nezam Ave, Tehran, Iran},
abstract = {Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.},
keywords = {adult, amputee, article, camera, case study, clinical article, comparative study, compression release stabilization, data analysis software, evaluation study, female, femoral shaft, foot prosthesis, gait, gluteus muscle, human, information processing device, IRCT20181021041400N1, ischial tuberosity, kinematics, knee prosthesis, leather belt wrap, limb amputation, male, MATLAB, medical device, middle aged, motion analysis system, orthopedic cast, orthopedic surgical equipment, Ottobock 3R20, pilot study, prosthesis design, quadrilateral socket, solid ankle cushioned heel foot, statistical model, step length, step time, step width, stride length, stride time, symmetry index, transfemoral socket, walking, walking speed, weight training, Wilcoxon signed ranks test},
pubstate = {published},
tppubtype = {article}
}
Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.
2023
Trinler, U.; Heitzmann, D. W. W.; Hitzeroth, S.; Alimusaj, M.; Rehg, M.; Hogan, A.
In: Prosthet. Orthot. Int., Bd. 47, Nr. 1, S. 94–100, 2023, ISSN: 0309-3646.
@article{Trinler2023,
title = {Biomechanical comparison of a 3D-printed prosthetic foot with conventional feet in people with transtibial amputation: A prospective cohort study},
author = {U. Trinler and D. W. W. Heitzmann and S. Hitzeroth and M. Alimusaj and M. Rehg and A. Hogan},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2022874959&from=export},
doi = {10.1097/PXR.0000000000000180},
issn = {0309-3646},
year = {2023},
date = {2023-08-01},
journal = {Prosthet. Orthot. Int.},
volume = {47},
number = {1},
pages = {94–100},
publisher = {Ovid Technologies (Wolters Kluwer Health)},
address = {U. Trinler, BG Klinik Ludwigshafen, Ludwig-Guttmann-Str. 13, Ludwigshafen, Germany},
abstract = {Introduction: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. Methods: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. Results: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. Conclusion: In principle, 3D-printed feet have advantages over conventional “off the shelf” feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Introduction: The method of 3D printing is increasingly gaining utilization in clinical applications and may support prosthetic fitting. The aim was to compare biomechanical outcomes of people with a transtibial amputation using a novel, individualizable, 3D-printed prosthetic foot (ComfyStep, Mecuris) with two conventional, widely used prosthetic feet during level ground walking using a 3D motion analysis system. Methods: Ten individuals with an unilateral transtibial amputation were fitted with 3 prosthetic feet (ComfyStep, Assure/Össur, DynamicMotion/Ottobock) using their current, well-fitting socket. They had at least 1 week of familiarization for each foot before gait analyses were conducted. Kinematics and kinetics as well as roll over shape (ROS) length and radius were calculated and compared between feet. Results: The sound side gait parameters of the participants were comparable when using different feet. However, there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in the following aspects: reduced range of motion, increased plantar flexion moment, reduced plantar flexion power, larger ROS radius, less favorable energy ratio, and higher overall stiffness. Conclusion: In principle, 3D-printed feet have advantages over conventional “off the shelf” feet, as their biomechanical characteristics could be adjusted more in detail according to the patient needs. Although, differences between conventional feet and the ComfyStep were shown. Whether these differences have a negative clinically relevant effect remains unclear. However, results suggest that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.
Manz, Sabina; Seifert, Dirk; Altenburg, Bjoern; Schmalz, Thomas; Dosen, Strahinja; Gonzalez-Vargas, Jose
In: Clinical Biomechanics, Bd. 106, S. 105988, 2023, ISSN: 0268-0033.
@article{Manz2023,
title = {Using embedded prosthesis sensors for clinical gait analyses in people with lower limb amputation: A feasibility study},
author = {Sabina Manz and Dirk Seifert and Bjoern Altenburg and Thomas Schmalz and Strahinja Dosen and Jose Gonzalez-Vargas},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2024655048&from=export},
doi = {10.1016/j.clinbiomech.2023.105988},
issn = {0268-0033},
year = {2023},
date = {2023-06-01},
journal = {Clinical Biomechanics},
volume = {106},
pages = {105988},
publisher = {Elsevier BV},
address = {J. Gonzalez-Vargas, Ottobock SE & Co. KGaA, Duderstadt, Germany},
abstract = {Background: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint. Methods: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors. Findings: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh). Interpretation: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Biomechanical gait analyses are typically performed in laboratory settings, and are associated with limitations due to space, marker placement, and tasks that are not representative of the real-world usage of lower limb prostheses. Therefore, the purpose of this study was to investigate the possibility of accurately measuring gait parameters using embedded sensors in a microprocessor-controlled knee joint. Methods: Ten participants were recruited for this study and equipped with a Genium X3 prosthetic knee joint. They performed level walking, stair/ramp descent, and ascent. During these tasks, kinematics and kinetics (sagittal knee and thigh segment angle, and knee moment) were recorded using an optical motion capture system and force plates (gold standard), as well as the prosthesis-embedded sensors. Root mean square errors, relative errors, correlation coefficients, and discrete outcome variables of clinical relevance were calculated and compared between the gold standard and the embedded sensors. Findings: The average root mean square errors were found to be 0.6°, 5.3°, and 0.08 Nm/kg, for the knee angle, thigh angle, and knee moment, respectively. The average relative errors were 0.75% for the knee angle, 11.67% for the thigh angle, and 9.66%, for the knee moment. The discrete outcome variables showed small but significant differences between the two measurement systems for a number of tasks (higher differences only at the thigh). Interpretation: The findings highlight the potential of prosthesis-embedded sensors to accurately measure gait parameters across a wide range of tasks. This paves the way for assessing prosthesis performance in realistic environments outside the lab.
2022
Ernst, M.; Altenburg, B.; Schmalz, T.; Kannenberg, A.; Bellmann, M.
Benefits of a microprocessor-controlled prosthetic foot for ascending and descending slopes Artikel
In: J. NeuroEng. Rehabil., Bd. 19, Nr. 1, 2022, ISSN: 1743-0003.
@article{Ernst2022,
title = {Benefits of a microprocessor-controlled prosthetic foot for ascending and descending slopes},
author = {M. Ernst and B. Altenburg and T. Schmalz and A. Kannenberg and M. Bellmann},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2014862458&from=export},
doi = {10.1186/s12984-022-00983-y},
issn = {1743-0003},
year = {2022},
date = {2022-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {19},
number = {1},
address = {M. Ernst, Research Biomechanics, CR&S, Ottobock SE & Co. KGaA, Göttingen, Germany},
abstract = {Background: Prosthetic feet are prescribed for persons with a lower-limb amputation to restore lost mobility. However, due to limited adaptability of their ankles and springs, situations like walking on slopes or uneven ground remain challenging. This study investigated to what extent a microprocessor-controlled prosthetic foot (MPF) facilitates walking on slopes. Methods: Seven persons each with a unilateral transtibial amputation (TTA) and unilateral transfemoral amputation (TFA) as well as ten able-bodied subjects participated. Participants were studied while using a MPF and their prescribed standard feet with fixed ankle attachments. The study investigated ascending and descending a 10° slope. Kinematic and kinetic data were recorded with a motion capture system. Biomechanical parameters, in particular leg joint angles, shank orientation and external joint moments of the prosthetics side were calculated. Results: Prosthetic feet- and subject group-dependent joint angle and moment characteristics were observed for both situations. The MPF showed a larger and situation-dependent ankle range of motion compared to the standard feet. Furthermore, it remained in a dorsiflexed position during swing. While ascending, the MPF adapted the dorsiflexion moment and reduced the knee extension moment. At vertical shank orientation, it reduced the knee extension moment by 26% for TFA and 49% for TTA compared to the standard feet. For descending, differences between feet in the biomechanical knee characteristics were found for the TTA group, but not for the TFA group. At the vertical shank angle during slope descent, TTA demonstrated a behavior of the ankle moment similar to able-bodied controls when using the MPF. Conclusions: The studied MPF facilitated walking on slopes by adapting instantaneously to inclinations and, thus, easing the forward rotation of the leg over the prosthetic foot compared to standard feet with a fixed ankle attachment with amputation-level dependent effect sizes. It assumed a dorsiflexed ankle angle during swing, enabled a larger ankle range of motion and reduced the moments acting on the residual knee of TTA compared to the prescribed prosthetic standard feet. For individuals with TFA, the prosthetic knee joint seems to play a more crucial role for walking on ramps than the foot.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Prosthetic feet are prescribed for persons with a lower-limb amputation to restore lost mobility. However, due to limited adaptability of their ankles and springs, situations like walking on slopes or uneven ground remain challenging. This study investigated to what extent a microprocessor-controlled prosthetic foot (MPF) facilitates walking on slopes. Methods: Seven persons each with a unilateral transtibial amputation (TTA) and unilateral transfemoral amputation (TFA) as well as ten able-bodied subjects participated. Participants were studied while using a MPF and their prescribed standard feet with fixed ankle attachments. The study investigated ascending and descending a 10° slope. Kinematic and kinetic data were recorded with a motion capture system. Biomechanical parameters, in particular leg joint angles, shank orientation and external joint moments of the prosthetics side were calculated. Results: Prosthetic feet- and subject group-dependent joint angle and moment characteristics were observed for both situations. The MPF showed a larger and situation-dependent ankle range of motion compared to the standard feet. Furthermore, it remained in a dorsiflexed position during swing. While ascending, the MPF adapted the dorsiflexion moment and reduced the knee extension moment. At vertical shank orientation, it reduced the knee extension moment by 26% for TFA and 49% for TTA compared to the standard feet. For descending, differences between feet in the biomechanical knee characteristics were found for the TTA group, but not for the TFA group. At the vertical shank angle during slope descent, TTA demonstrated a behavior of the ankle moment similar to able-bodied controls when using the MPF. Conclusions: The studied MPF facilitated walking on slopes by adapting instantaneously to inclinations and, thus, easing the forward rotation of the leg over the prosthetic foot compared to standard feet with a fixed ankle attachment with amputation-level dependent effect sizes. It assumed a dorsiflexed ankle angle during swing, enabled a larger ankle range of motion and reduced the moments acting on the residual knee of TTA compared to the prescribed prosthetic standard feet. For individuals with TFA, the prosthetic knee joint seems to play a more crucial role for walking on ramps than the foot.
Pröbsting, E.; Altenburg, B.; Bellmann, M.; Krug, K.; Schmalz, T.
In: Prosthet. Orthot. Int., Bd. 46, Nr. 4, S. 306–313, 2022, ISSN: 0309-3646.
@article{Proebsting2022,
title = {How does ankle power on the prosthetic side influence loading parameters on the sound side during level walking of persons with transfemoral amputation?},
author = {E. Pröbsting and B. Altenburg and M. Bellmann and K. Krug and T. Schmalz},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2019708323&from=export},
doi = {10.1097/pxr.0000000000000099},
issn = {0309-3646},
year = {2022},
date = {2022-01-01},
journal = {Prosthet. Orthot. Int.},
volume = {46},
number = {4},
pages = {306–313},
address = {E. Pröbsting, Ottobock SE & Co. KGaA, Herrmann-Rein-Straße 2a, Göttingen, Germany},
abstract = {Background:Increased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side.Objective:To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters.Study design:Interventional cross sectional study.Methods:Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used.Results:The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity.Conclusions:The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background:Increased ankle power on the prosthetic side seems to decrease biomechanical loading parameters on the sound side. This assumption is based on biomechanical comparisons of different foot constructions. However, such study designs could not show whether the amount of ankle power solely influences the sound side.Objective:To analyze the influence of divergent ankle power, resulting from different foot constructions and from different ankle power settings, on the sound side loading parameters.Study design:Interventional cross sectional study.Methods:Level walking of transfemoral amputees with a microprocessor knee joint and Solid Ankle Cushioned Heel (SACH), energy storing and returning (ESR) and powered foot (PF) was analyzed. The PF was adapted in three configurations: without power (np), low power (lp), and optimal power (op). An optoelectronic camera system with 12 cameras and two force plates were used.Results:The ankle power on the prosthetic side shows significant differences about foot types and different settings of the PF. The knee adduction moment, the knee flexion moment, and the vertical ground reaction forces on the sound side were significantly reduced with PF_op and ESR in comparison to SACH. When analyzing these parameters for the different PF configurations, only some show significant results at normal velocity.Conclusions:The additional positive mechanical work for an active push off in the PF tends to have a relieving effect. The biomechanical sound side loading parameters are reduced with PF_op in comparison to SACH and ESR, resulting in a relief of the sound side of lower limb amputees.
2021
Yazdani, M.; Hajiaghaei, B.; Saeedi, H.; Kamali, M.; Yousefi, M.
In: Curr. Orthop. Pract., Bd. 32, Nr. 5, S. 505–511, 2021, ISSN: 1940-7041.
@article{Yazdani2021,
title = {Does the socket design affect symmetry and spatiotemporal gait parameters? A case series of two transfemoral amputees},
author = {M. Yazdani and B. Hajiaghaei and H. Saeedi and M. Kamali and M. Yousefi},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L635549609&from=export},
doi = {10.1097/bco.0000000000001022},
issn = {1940-7041},
year = {2021},
date = {2021-01-01},
journal = {Curr. Orthop. Pract.},
volume = {32},
number = {5},
pages = {505–511},
address = {B. Hajiaghaei, Department of Orthotics and Prosthetics, School of Rehabilitation Sciences, Iran University of Medical Sciences, Nezam Ave, Tehran, Iran},
abstract = {Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Socket design is thought to improve gait performance and symmetry as the other components of the prosthesis do. This study focused on the comparison of two different sockets in transfemoral amputee patients to evaluate the influence of the socket designs on gait symmetry and various spatiotemporal gait parameters. Methods: Two transfemoral amputees participated in this case series study. They were asked to walk with the quadrilateral and the new modified sockets along a 10-meter walkway. The marker-based motion capture system recorded the spatiotemporal gait data during all walking trials. Kinematic data were compared between the two test conditions using the Wilcoxon signed-rank test and Symmetry Index. Results: The new socket increased velocity and cadence and reduced step width in both amputees, compared with the quadrilateral sockets. However, a good symmetry was observed in step length, stride length, step time, and stride time within two limbs by both sockets (SI ≤10). Conclusions: The design of sockets in this study had no observed effect on gait symmetry; however, the new socket increased velocity and cadence and reduced width step in both patients compared with the quadrilateral socket. Level of Evidence: Level IV.
2017
Ernst, M.; Altenburg, B.; Bellmann, M.; Schmalz, T.
In: J. NeuroEng. Rehabil., Bd. 14, Nr. 1, 2017, ISSN: 1743-0003.
@article{Ernst2017,
title = {Standing on slopes - How current microprocessor-controlled prosthetic feet support transtibial and transfemoral amputees in an everyday task},
author = {M. Ernst and B. Altenburg and M. Bellmann and T. Schmalz},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L619264869&from=export},
doi = {10.1186/s12984-017-0322-2},
issn = {1743-0003},
year = {2017},
date = {2017-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {14},
number = {1},
address = {M. Ernst, Research Biomechanics, CRandS, Otto Bock HealthCare GmbH, Göttingen, Germany},
abstract = {Background: Conventional prosthetic feet like energy storage and return feet provide only a limited range of ankle motion compared to human ones. In order to overcome the poor rotational adaptability, prosthetic manufacturers developed different prosthetic feet with an additional rotational joint and implemented active control in different states. It was the aim of the study to investigate to what extent these commercially available microprocessor-controlled prosthetic feet support a natural posture while standing on inclines and which concept is most beneficial for lower limb amputees. Methods: Four unilateral transtibial and four unilateral transfemoral amputees participated in the study. Each of the subjects wore five different microprocessor-controlled prosthetic feet in addition to their everyday feet. The subjects were asked to stand on slopes of different inclinations (level ground, upward slope of 10°, and downward slope of -10°). Vertical ground reaction forces, joint torques and joint angles in the sagittal plane were measured for both legs separately for the different situations and compared to a non-amputee reference group. Results: Differences in the biomechanical parameters were observed between the different prosthetic feet and compared to the reference group for the investigated situations. They were most prominent while standing on a downward slope. For example, on the prosthetic side, the vertical ground reaction force is reduced by about 20%, and the torque about the knee acts to flex the joint for feet that are not capable of a full adaptation to the downward slope. In contrast, fully adaptable feet with an auto-adaptive dorsiflexion stop show no changes in vertical ground reaction forces and knee extending torques. Conclusions: A prosthetic foot that provides both, an auto-adaptive dorsiflexion stop and a sufficient range of motion for fully adapting to inclinations appears to be the key element in the prosthetic fitting for standing on inclinations in lower limb amputees. In such situations, this prosthetic concept appears superior to both, conventional feet with passive structures as well as feet that solely provide a sufficient range of motion. The results also indicate that both, transfemoral and transtibial amputees benefit from such a foot.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Conventional prosthetic feet like energy storage and return feet provide only a limited range of ankle motion compared to human ones. In order to overcome the poor rotational adaptability, prosthetic manufacturers developed different prosthetic feet with an additional rotational joint and implemented active control in different states. It was the aim of the study to investigate to what extent these commercially available microprocessor-controlled prosthetic feet support a natural posture while standing on inclines and which concept is most beneficial for lower limb amputees. Methods: Four unilateral transtibial and four unilateral transfemoral amputees participated in the study. Each of the subjects wore five different microprocessor-controlled prosthetic feet in addition to their everyday feet. The subjects were asked to stand on slopes of different inclinations (level ground, upward slope of 10°, and downward slope of -10°). Vertical ground reaction forces, joint torques and joint angles in the sagittal plane were measured for both legs separately for the different situations and compared to a non-amputee reference group. Results: Differences in the biomechanical parameters were observed between the different prosthetic feet and compared to the reference group for the investigated situations. They were most prominent while standing on a downward slope. For example, on the prosthetic side, the vertical ground reaction force is reduced by about 20%, and the torque about the knee acts to flex the joint for feet that are not capable of a full adaptation to the downward slope. In contrast, fully adaptable feet with an auto-adaptive dorsiflexion stop show no changes in vertical ground reaction forces and knee extending torques. Conclusions: A prosthetic foot that provides both, an auto-adaptive dorsiflexion stop and a sufficient range of motion for fully adapting to inclinations appears to be the key element in the prosthetic fitting for standing on inclinations in lower limb amputees. In such situations, this prosthetic concept appears superior to both, conventional feet with passive structures as well as feet that solely provide a sufficient range of motion. The results also indicate that both, transfemoral and transtibial amputees benefit from such a foot.
Rigney, S. M.; Simmons, A.; Kark, L.
Mechanical characterization and comparison of energy storage and return prostheses Artikel
In: Med. Eng. Phys., Bd. 41, S. 90–96, 2017, ISSN: 1350-4533.
@article{Rigney2017,
title = {Mechanical characterization and comparison of energy storage and return prostheses},
author = {S. M. Rigney and A. Simmons and L. Kark},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L614136635&from=export},
doi = {10.1016/j.medengphy.2017.01.003},
issn = {1350-4533},
year = {2017},
date = {2017-01-01},
journal = {Med. Eng. Phys.},
volume = {41},
pages = {90–96},
address = {L. Kark, Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia},
abstract = {The suitability of finite element analysis (FEA) for standardizing the mechanical characterization of energy storage and return (ESAR) prostheses was investigated. A methodology consisting of both experimental and numerical analysis was proposed and trialed for the Vari-flex® ModularTM, Flex-foot Cheetah and Cheetah Xtreme by Össur® and a 1E90 Sprinter by Ottobock®. Gait analysis was conducted to determine suitable orientation angles for non-destructive testing (NDT) of the ESAR prostheses followed by a quasi-static inverse FEA procedure within COMSOL Multiphysics®, where the NDT conditions were replicated to determine the homogenized material properties of the prostheses. The prostheses’ loading response under bodyweight for an 80 kg person was then simulated, using both Eigenfrequency and time-dependent analysis. The apparent stiffness under bodyweight was determined to be 94.7, 48.6, 57.4 and 65.0 Nmm−1 for the Vari-flex® ModularTM, Flex-foot Cheetah, Cheetah Xtreme and 1E90 Sprinter, respectively. Both the energy stored and returned by the prostheses varied negatively with stiffness, yet the overall efficiency of the prostheses were similar, at 52.7, 52.0, 51.7 and 52.4% for the abovementioned prostheses. The proposed methodology allows the standardized assessment and comparison of ESAR prostheses without the confounding influences of subject-specific gait characteristics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The suitability of finite element analysis (FEA) for standardizing the mechanical characterization of energy storage and return (ESAR) prostheses was investigated. A methodology consisting of both experimental and numerical analysis was proposed and trialed for the Vari-flex® ModularTM, Flex-foot Cheetah and Cheetah Xtreme by Össur® and a 1E90 Sprinter by Ottobock®. Gait analysis was conducted to determine suitable orientation angles for non-destructive testing (NDT) of the ESAR prostheses followed by a quasi-static inverse FEA procedure within COMSOL Multiphysics®, where the NDT conditions were replicated to determine the homogenized material properties of the prostheses. The prostheses’ loading response under bodyweight for an 80 kg person was then simulated, using both Eigenfrequency and time-dependent analysis. The apparent stiffness under bodyweight was determined to be 94.7, 48.6, 57.4 and 65.0 Nmm−1 for the Vari-flex® ModularTM, Flex-foot Cheetah, Cheetah Xtreme and 1E90 Sprinter, respectively. Both the energy stored and returned by the prostheses varied negatively with stiffness, yet the overall efficiency of the prostheses were similar, at 52.7, 52.0, 51.7 and 52.4% for the abovementioned prostheses. The proposed methodology allows the standardized assessment and comparison of ESAR prostheses without the confounding influences of subject-specific gait characteristics.
2016
Beck, O. N.; Taboga, P.; Grabowski, A. M.
Characterizing the mechanical properties of running-specific prostheses Artikel
In: PLoS ONE, Bd. 11, Nr. 12, 2016, ISSN: 1932-6203.
@article{Beck2016,
title = {Characterizing the mechanical properties of running-specific prostheses},
author = {O. N. Beck and P. Taboga and A. M. Grabowski},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L613668924&from=export},
doi = {10.1371/journal.pone.0168298},
issn = {1932-6203},
year = {2016},
date = {2016-01-01},
journal = {PLoS ONE},
volume = {11},
number = {12},
abstract = {The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.
Williams, M. R.; D'Andrea, S.; Herr, H. M.
Impact on gait biomechanics of using an active variable impedance prosthetic knee Artikel
In: J. NeuroEng. Rehabil., Bd. 13, Nr. 1, 2016, ISSN: 1743-0003.
@article{Williams2016,
title = {Impact on gait biomechanics of using an active variable impedance prosthetic knee},
author = {M. R. Williams and S. D'Andrea and H. M. Herr},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L610660431&from=export},
doi = {10.1186/s12984-016-0159-0},
issn = {1743-0003},
year = {2016},
date = {2016-01-01},
journal = {J. NeuroEng. Rehabil.},
volume = {13},
number = {1},
address = {M.R. Williams, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States},
abstract = {Background: An above knee amputation can have a significant impact on gait, with substantial deviations in inter-leg symmetry, step length, hip exertion and upper body involvement even when using a current clinical standard of care prosthesis. These differences can produce gait that is less efficient and less comfortable, resulting in slower and shorter distance walking, particularly with long term use. Methods: A robotic variable impedance prosthetic knee (VI Knee) was tested with five individuals (N = 5) with unilateral amputation above the knee at fixed speeds both above and below their normal walking speed. Subject gait was measured as they walked along an instrumented walkway via optical motion capture and force plates in the floor. Each subject's gait while using the VI Knee was compared to that while using their standard of care knee (OttoBock C-Leg). Results: Significant differences (p < 0.05) in walking between the standard of care and variable impedance devices were seen in step length and hip range of motion symmetries, hip extension moment, knee power and torso lean angle. While using the VI Knee, several subjects demonstrated statistically significant improvements in gait, particularly in increased hip range of motion symmetry between affected and intact sides, greater prosthesis knee power and in reducing upper body involvement in the walking task by decreasing forward and affected side lean and reducing the pelvis-torso twist coupling. These changes to torso posture during gait also resulted in increased terminal stance hip flexion moment across subjects. Detriments to gait were also observed in that some subjects exhibited decreased step length symmetry while using the VI Knee compared to the C-Leg. Conclusions: The knee tested represents the potential to improve gait biomechanics and reduce upper body involvement in persons with above knee amputation compared to current standard of care devices. While using the VI Knee, subjects demonstrated statistically significant improvements in several aspects of gait though some were worsened while using the device. It is possible that these negative effects may be mitigated through longer term training and experience with the VI Knee. Given the demonstrated benefits and the potential to reduce or eliminate detriments through training, using a powered device like the VI Knee, particularly over an extended period of time, may help to improve walking performance and comfort.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: An above knee amputation can have a significant impact on gait, with substantial deviations in inter-leg symmetry, step length, hip exertion and upper body involvement even when using a current clinical standard of care prosthesis. These differences can produce gait that is less efficient and less comfortable, resulting in slower and shorter distance walking, particularly with long term use. Methods: A robotic variable impedance prosthetic knee (VI Knee) was tested with five individuals (N = 5) with unilateral amputation above the knee at fixed speeds both above and below their normal walking speed. Subject gait was measured as they walked along an instrumented walkway via optical motion capture and force plates in the floor. Each subject's gait while using the VI Knee was compared to that while using their standard of care knee (OttoBock C-Leg). Results: Significant differences (p < 0.05) in walking between the standard of care and variable impedance devices were seen in step length and hip range of motion symmetries, hip extension moment, knee power and torso lean angle. While using the VI Knee, several subjects demonstrated statistically significant improvements in gait, particularly in increased hip range of motion symmetry between affected and intact sides, greater prosthesis knee power and in reducing upper body involvement in the walking task by decreasing forward and affected side lean and reducing the pelvis-torso twist coupling. These changes to torso posture during gait also resulted in increased terminal stance hip flexion moment across subjects. Detriments to gait were also observed in that some subjects exhibited decreased step length symmetry while using the VI Knee compared to the C-Leg. Conclusions: The knee tested represents the potential to improve gait biomechanics and reduce upper body involvement in persons with above knee amputation compared to current standard of care devices. While using the VI Knee, subjects demonstrated statistically significant improvements in several aspects of gait though some were worsened while using the device. It is possible that these negative effects may be mitigated through longer term training and experience with the VI Knee. Given the demonstrated benefits and the potential to reduce or eliminate detriments through training, using a powered device like the VI Knee, particularly over an extended period of time, may help to improve walking performance and comfort.