TPress
1.
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.
2.
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.
3.
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.
4.
Köhler, T. M.; Blumentritt, S.; Braatz, F.; Bellmann, M.
In: Gait Posture, Bd. 89, S. 169–177, 2021, ISSN: 0966-6362.
Abstract | Links | Schlagwörter: above knee amputation, adduction, adult, article, biomechanics, camera, clinical article, controlled study, female, femoral knee prosthesis, gait, Genium, ground reaction force, human, male, microprocessor, motion analysis system, pelvis, prosthetic alignment, step length, transfemoral amputation, transfemoral prosthetic socket, Triton, trunk, tyloxapol, Vicon Bonita, walking, walking speed
@article{Koehler2021,
title = {The impact of transfemoral socket adduction on pelvic and trunk stabilization during level walking - A biomechanical study},
author = {T. M. Köhler and S. Blumentritt and F. Braatz and M. Bellmann},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2013710687&from=export},
doi = {10.1016/j.gaitpost.2021.06.024},
issn = {0966-6362},
year = {2021},
date = {2021-09-01},
journal = {Gait Posture},
volume = {89},
pages = {169–177},
publisher = {Elsevier BV},
address = {T.M. Köhler, Ottobock SE & Co. KGaA, Hermann-Rein-Straße 2a, Göttingen, Germany},
abstract = {Background: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. Research question: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? Methods: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. Results: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. Significance: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.},
keywords = {above knee amputation, adduction, adult, article, biomechanics, camera, clinical article, controlled study, female, femoral knee prosthesis, gait, Genium, ground reaction force, human, male, microprocessor, motion analysis system, pelvis, prosthetic alignment, step length, transfemoral amputation, transfemoral prosthetic socket, Triton, trunk, tyloxapol, Vicon Bonita, walking, walking speed},
pubstate = {published},
tppubtype = {article}
}
Background: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. Research question: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? Methods: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. Results: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. Significance: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.
5.
Ernst, M.; Altenburg, B.; Bellmann, M.; Schmalz, T.
In: J. NeuroEng. Rehabil., Bd. 14, Nr. 1, 2017, ISSN: 1743-0003.
Abstract | Links | Schlagwörter: adult, article, autoadaptive dorsiflexion stop, controlled study, foot prosthesis, Genium, ground reaction force, human, human experiment, informed consent, joint angle, joint torque, leg amputation, male, microprocessor, microprocessor controlled prosthetic feet, musculoskeletal function, musculoskeletal system parameters, priority journal, standing, task performance, transfemoral amputation, transtibial amputation, vertical ground reaction force
@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 = {adult, article, autoadaptive dorsiflexion stop, controlled study, foot prosthesis, Genium, ground reaction force, human, human experiment, informed consent, joint angle, joint torque, leg amputation, male, microprocessor, microprocessor controlled prosthetic feet, musculoskeletal function, musculoskeletal system parameters, priority journal, standing, task performance, transfemoral amputation, transtibial amputation, vertical ground reaction force},
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.
2023
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
Köhler, T. M.; Blumentritt, S.; Braatz, F.; Bellmann, M.
In: Gait Posture, Bd. 89, S. 169–177, 2021, ISSN: 0966-6362.
Abstract | Links | Schlagwörter: above knee amputation, adduction, adult, article, biomechanics, camera, clinical article, controlled study, female, femoral knee prosthesis, gait, Genium, ground reaction force, human, male, microprocessor, motion analysis system, pelvis, prosthetic alignment, step length, transfemoral amputation, transfemoral prosthetic socket, Triton, trunk, tyloxapol, Vicon Bonita, walking, walking speed
@article{Koehler2021,
title = {The impact of transfemoral socket adduction on pelvic and trunk stabilization during level walking - A biomechanical study},
author = {T. M. Köhler and S. Blumentritt and F. Braatz and M. Bellmann},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2013710687&from=export},
doi = {10.1016/j.gaitpost.2021.06.024},
issn = {0966-6362},
year = {2021},
date = {2021-09-01},
journal = {Gait Posture},
volume = {89},
pages = {169–177},
publisher = {Elsevier BV},
address = {T.M. Köhler, Ottobock SE & Co. KGaA, Hermann-Rein-Straße 2a, Göttingen, Germany},
abstract = {Background: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. Research question: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? Methods: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. Results: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. Significance: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.},
keywords = {above knee amputation, adduction, adult, article, biomechanics, camera, clinical article, controlled study, female, femoral knee prosthesis, gait, Genium, ground reaction force, human, male, microprocessor, motion analysis system, pelvis, prosthetic alignment, step length, transfemoral amputation, transfemoral prosthetic socket, Triton, trunk, tyloxapol, Vicon Bonita, walking, walking speed},
pubstate = {published},
tppubtype = {article}
}
Background: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. Research question: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? Methods: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. Results: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. Significance: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.
2017
Ernst, M.; Altenburg, B.; Bellmann, M.; Schmalz, T.
In: J. NeuroEng. Rehabil., Bd. 14, Nr. 1, 2017, ISSN: 1743-0003.
Abstract | Links | Schlagwörter: adult, article, autoadaptive dorsiflexion stop, controlled study, foot prosthesis, Genium, ground reaction force, human, human experiment, informed consent, joint angle, joint torque, leg amputation, male, microprocessor, microprocessor controlled prosthetic feet, musculoskeletal function, musculoskeletal system parameters, priority journal, standing, task performance, transfemoral amputation, transtibial amputation, vertical ground reaction force
@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 = {adult, article, autoadaptive dorsiflexion stop, controlled study, foot prosthesis, Genium, ground reaction force, human, human experiment, informed consent, joint angle, joint torque, leg amputation, male, microprocessor, microprocessor controlled prosthetic feet, musculoskeletal function, musculoskeletal system parameters, priority journal, standing, task performance, transfemoral amputation, transtibial amputation, vertical ground reaction force},
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.
2023
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
Köhler, T. M.; Blumentritt, S.; Braatz, F.; Bellmann, M.
In: Gait Posture, Bd. 89, S. 169–177, 2021, ISSN: 0966-6362.
@article{Koehler2021,
title = {The impact of transfemoral socket adduction on pelvic and trunk stabilization during level walking - A biomechanical study},
author = {T. M. Köhler and S. Blumentritt and F. Braatz and M. Bellmann},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2013710687&from=export},
doi = {10.1016/j.gaitpost.2021.06.024},
issn = {0966-6362},
year = {2021},
date = {2021-09-01},
journal = {Gait Posture},
volume = {89},
pages = {169–177},
publisher = {Elsevier BV},
address = {T.M. Köhler, Ottobock SE & Co. KGaA, Hermann-Rein-Straße 2a, Göttingen, Germany},
abstract = {Background: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. Research question: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? Methods: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. Results: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. Significance: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: It is common practice to align transfemoral prosthetic sockets in adduction, due to the physiologic, adducted femoral alignment in unimpaired legs. An adducted femoral and socket alignment helps tightening hip abductors to stabilize the pelvis and reduce pelvic and trunk related compensatory movements. Research question: How do different socket adduction conditions (SAC) of transfemoral sockets affect pelvic and trunk stabilization during level ground walking in the frontal plane? Methods: Seven persons with transfemoral amputation with medium residual limb length participated in this study. The prosthetic alignment in the sagittal plane was performed according to established recommendations. SAC varied (0°, 3°, 6°, 9°). Kinematic and kinetic parameters were recorded in a gait laboratory with a 12-camera optoelectronic system and two piezoelectric force plates embedded in a 12-m walkway. The measurements were performed during level ground walking with self-selected comfortable gait speed. Results: In the frontal plane, nearly all investigated kinematic and kinetic parameters showed a strong correlation with the SAC. The pelvis was raised on the contralateral side throughout the gait cycle with increasing SAC. During the prosthetic side stance phase, the mean shoulder obliquity and mean lateral trunk lean to the prosthetic side tended to be reduced with increased SAC. Prosthetic side hip abduction moment decreased with increasing SAC. Significance: The results confirm that transfemoral SAC contributes to pelvic stabilization and reduced compensatory movements of the pelvis and trunk. Transfemoral SAC of 6 ± 1° for bench alignment seems adequate for amputees with medium residual limb length. However, the optimum value for the individual patient may differ slightly.
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.
2014
Whitehead, J. M. Aldridge; Wolf, E. J.; Scoville, C. R.; Wilken, J. M.
In: Clin. Orthop. Relat. Res., Bd. 472, Nr. 10, S. 3093–3101, 2014, ISSN: 0009-921X.
@article{AldridgeWhitehead2014,
title = {Does a Microprocessor-controlled Prosthetic Knee Affect Stair Ascent Strategies in Persons With Transfemoral Amputation?},
author = {J. M. Aldridge Whitehead and E. J. Wolf and C. R. Scoville and J. M. Wilken},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L608263443&from=export},
doi = {10.1007/s11999-014-3484-2},
issn = {0009-921X},
year = {2014},
date = {2014-10-01},
journal = {Clin. Orthop. Relat. Res.},
volume = {472},
number = {10},
pages = {3093–3101},
publisher = {Ovid Technologies (Wolters Kluwer Health)},
address = {J.M. Wilken, DOD-VA Extremity Trauma and Amputation Center of Excellence, Center for the Intrepid, Department of Orthopaedics and Rehabilitation, Brooke Army Medical Center, 3551 Roger Brooke Drive, Ft Sam Houston, TX, United States},
abstract = {Background: Stair ascent can be difficult for individuals with transfemoral amputation because of the loss of knee function. Most individuals with transfemoral amputation use either a step-to-step (nonreciprocal, advancing one stair at a time) or skip-step strategy (nonreciprocal, advancing two stairs at a time), rather than a step-over-step (reciprocal) strategy, because step-to-step and skip-step allow the leading intact limb to do the majority of work. A new microprocessor-controlled knee (Ottobock X2®) uses flexion/extension resistance to allow step-over-step stair ascent. Questions/Purposes: We compared self-selected stair ascent strategies between conventional and X2® prosthetic knees, examined between-limb differences, and differentiated stair ascent mechanics between X2® users and individuals without amputation. We also determined which factors are associated with differences in knee position during initial contact and swing within X2® users. Methods: Fourteen individuals with transfemoral amputation participated in stair ascent sessions while using conventional and X2® knees. Ten individuals without amputation also completed a stair ascent session. Lower-extremity stair ascent joint angles, moment, and powers and ground reaction forces were calculated using inverse dynamics during self-selected strategy and cadence and controlled cadence using a step-over-step strategy. Results: One individual with amputation self-selected a step-over-step strategy while using a conventional knee, while 10 individuals self-selected a step-over-step strategy while using X2® knees. Individuals with amputation used greater prosthetic knee flexion during initial contact (32.5°},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Background: Stair ascent can be difficult for individuals with transfemoral amputation because of the loss of knee function. Most individuals with transfemoral amputation use either a step-to-step (nonreciprocal, advancing one stair at a time) or skip-step strategy (nonreciprocal, advancing two stairs at a time), rather than a step-over-step (reciprocal) strategy, because step-to-step and skip-step allow the leading intact limb to do the majority of work. A new microprocessor-controlled knee (Ottobock X2®) uses flexion/extension resistance to allow step-over-step stair ascent. Questions/Purposes: We compared self-selected stair ascent strategies between conventional and X2® prosthetic knees, examined between-limb differences, and differentiated stair ascent mechanics between X2® users and individuals without amputation. We also determined which factors are associated with differences in knee position during initial contact and swing within X2® users. Methods: Fourteen individuals with transfemoral amputation participated in stair ascent sessions while using conventional and X2® knees. Ten individuals without amputation also completed a stair ascent session. Lower-extremity stair ascent joint angles, moment, and powers and ground reaction forces were calculated using inverse dynamics during self-selected strategy and cadence and controlled cadence using a step-over-step strategy. Results: One individual with amputation self-selected a step-over-step strategy while using a conventional knee, while 10 individuals self-selected a step-over-step strategy while using X2® knees. Individuals with amputation used greater prosthetic knee flexion during initial contact (32.5°
Kistenberg, R. S.
Prosthetic choices for people with leg and arm amputations Artikel
In: Phys. Med. Rehabil. Clin. North Am., Bd. 25, Nr. 1, S. 93–115, 2014, ISSN: 1558-1381.
@article{Kistenberg2014,
title = {Prosthetic choices for people with leg and arm amputations},
author = {R. S. Kistenberg},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L370343297&from=export},
doi = {10.1016/j.pmr.2013.10.001},
issn = {1558-1381},
year = {2014},
date = {2014-01-01},
journal = {Phys. Med. Rehabil. Clin. North Am.},
volume = {25},
number = {1},
pages = {93–115},
address = {R.S. Kistenberg, Georgia Institute of Technology, School of Applied Physiology, 555 14th Street, Atlanta, GA 30318, United States},
abstract = {New technology and materials have advanced prosthetic designs to enable people who rely on artificial limbs to achieve feats never dreamed before. However, the latest and the greatest technology is not appropriate for everyone. The aim of this article is to present contemporary options that are available for people who rely on artificial limbs to enhance their quality of life for mobility and independence. © 2014 Elsevier Inc.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
New technology and materials have advanced prosthetic designs to enable people who rely on artificial limbs to achieve feats never dreamed before. However, the latest and the greatest technology is not appropriate for everyone. The aim of this article is to present contemporary options that are available for people who rely on artificial limbs to enhance their quality of life for mobility and independence. © 2014 Elsevier Inc.
2013
Komolafe, O.; Wood, S.; Caldwell, R.; Hansen, A.; Fatone, S.
Methods for characterization of mechanical and electrical prosthetic vacuum pumps Artikel
In: J. Rehabil. Res. Dev., Bd. 50, Nr. 8, S. 1069–1078, 2013, ISSN: 1938-1352.
@article{Komolafe2013,
title = {Methods for characterization of mechanical and electrical prosthetic vacuum pumps},
author = {O. Komolafe and S. Wood and R. Caldwell and A. Hansen and S. Fatone},
url = {https://www.embase.com/search/results?subaction=viewrecord&id=L370540897&from=export},
doi = {10.1682/jrrd.2012.11.0204},
issn = {1938-1352},
year = {2013},
date = {2013-01-01},
journal = {J. Rehabil. Res. Dev.},
volume = {50},
number = {8},
pages = {1069–1078},
address = {S. Fatone, Northwestern University, Prosthetics-Orthotics Center, 680 N Lake Shore Dr, Suite 1100, Chicago, IL 60611, United States},
abstract = {Despite increasingly widespread adoption of vacuum- assisted suspension systems in prosthetic clinical practices, there remain gaps in the body of scientific knowledge guiding clinicians' choices of existing products. In this study, we identified important pump-performance metrics and developed techniques to objectively characterize the evacuation performance of prosthetic vacuum pumps. The sensitivity of the proposed techniques was assessed by characterizing the evacuation performance of two electrical (Harmony e-Pulse [Ottobock; Duderstadt, Germany] and LimbLogic VS [Ohio Willow Wood; Mt. Sterling, Ohio]) and three mechanical (Harmony P2, Harmony HD, and Harmony P3 [Ottobock]) prosthetic pumps in bench-top testing. Five fixed volume chambers ranging from 33 cm3 (2 in.3) to 197 cm3 (12 in.3) were used to represent different air volume spaces between a prosthetic socket and a liner-clad residual limb. All measurements were obtained at a vacuum gauge pressure of 57.6 kPa (17 inHg). The proposed techniques demonstrated sensitivity to the different electrical and mechanical pumps and, to a lesser degree, to the different setting adjustments of each pump. The sensitivity was less pronounced for the mechanical pumps, and future improvements for testing of mechanical vacuum pumps were proposed. Overall, this study successfully offers techniques feasible as standards for assessing the evacuation performance of prosthetic vacuum pump devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Despite increasingly widespread adoption of vacuum- assisted suspension systems in prosthetic clinical practices, there remain gaps in the body of scientific knowledge guiding clinicians' choices of existing products. In this study, we identified important pump-performance metrics and developed techniques to objectively characterize the evacuation performance of prosthetic vacuum pumps. The sensitivity of the proposed techniques was assessed by characterizing the evacuation performance of two electrical (Harmony e-Pulse [Ottobock; Duderstadt, Germany] and LimbLogic VS [Ohio Willow Wood; Mt. Sterling, Ohio]) and three mechanical (Harmony P2, Harmony HD, and Harmony P3 [Ottobock]) prosthetic pumps in bench-top testing. Five fixed volume chambers ranging from 33 cm3 (2 in.3) to 197 cm3 (12 in.3) were used to represent different air volume spaces between a prosthetic socket and a liner-clad residual limb. All measurements were obtained at a vacuum gauge pressure of 57.6 kPa (17 inHg). The proposed techniques demonstrated sensitivity to the different electrical and mechanical pumps and, to a lesser degree, to the different setting adjustments of each pump. The sensitivity was less pronounced for the mechanical pumps, and future improvements for testing of mechanical vacuum pumps were proposed. Overall, this study successfully offers techniques feasible as standards for assessing the evacuation performance of prosthetic vacuum pump devices.