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@article{Ernst2020,

title = {Characterizing adaptations of prosthetic feet in the frontal plane},

author = {M. Ernst and B. Altenburg and T. Schmalz},

url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005154580&from=export},

doi = {10.1177/0309364620917838},

issn = {0309-3646},

year  = {2020},

date = {2020-01-01},

journal = {Prosthet. Orthot. Int.},

volume = {44},

number = {4},

pages = {225–233},

address = {M. Ernst, Research Biomechanics, Clinical Research and Services, Ottobock SE Co. KGaA, Göttingen, Germany},

abstract = {Background: Energy-storage and return feet incorporate various design features including split toes. As a potential improvement, an energy-storage and return foot with a dedicated ankle joint was recently introduced allowing for easily accessible inversion/eversion movement. However, the adaptability of energy-storage and return feet to uneven ground and the effects on biomechanical and clinical parameters have not been investigated in detail. Objectives: To investigate the design-related ability of prosthetic feet to adapt to cross slopes and derive a theoretical model. Study design: Mechanical testing and characterization. Methods: Mechanical adaptation to cross slopes was investigated for six prosthetic feet measured by a motion capture system. A theoretical model linking the measured data with adaptations is proposed. Results: The type and degree of adaptation depends on the foot design, for example, stiffness, split toe or continuous carbon forefoot, and additional ankle joint. The model used shows high correlations with the measured data for all feet. Conclusions: The ability of prosthetic feet to adapt to uneven ground is design-dependent. The split-toe feet adapted better to cross slopes than those with continuous carbon forefeet. Joints enhance this further by allowing for additional inversion and eversion. The influence on biomechanical and clinical parameters should be assessed in future studies. Clinical relevance: Knowing foot-specific ability to adapt to uneven ground may help in selecting an appropriate prosthetic foot for persons with a lower limb amputation. Faster and more comprehensive adaptations to uneven ground may lower the need for compensations and therefore increase user safety.},

keywords = {arm prosthesis, arthrodesis, article, Axtion, biomechanics, bone conduction, finite element analysis, forefoot, histology, human, joint function, mathematical model, motion analysis system, osteoarthritis, Pacifica LP, Pro Flex LP, Prototype ESRJ, subtalar joint, theoretical model, Triton LP},

pubstate = {published},

tppubtype = {article}

}

@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 = {1E90 Sprinter, article, biomechanics, body weight, Cheetah Xtreme, comparative study, controlled study, female, finite element analysis, Flex-foot Cheetah, foot prosthesis, force, gait, human, human experiment, mechanical torsion, rigidity, simulation, Vari-flex Modular},

pubstate = {published},

tppubtype = {article}

}

@article{Ernst2020,

title = {Characterizing adaptations of prosthetic feet in the frontal plane},

author = {M. Ernst and B. Altenburg and T. Schmalz},

url = {https://www.embase.com/search/results?subaction=viewrecord&id=L2005154580&from=export},

doi = {10.1177/0309364620917838},

issn = {0309-3646},

year  = {2020},

date = {2020-01-01},

journal = {Prosthet. Orthot. Int.},

volume = {44},

number = {4},

pages = {225–233},

address = {M. Ernst, Research Biomechanics, Clinical Research and Services, Ottobock SE Co. KGaA, Göttingen, Germany},

abstract = {Background: Energy-storage and return feet incorporate various design features including split toes. As a potential improvement, an energy-storage and return foot with a dedicated ankle joint was recently introduced allowing for easily accessible inversion/eversion movement. However, the adaptability of energy-storage and return feet to uneven ground and the effects on biomechanical and clinical parameters have not been investigated in detail. Objectives: To investigate the design-related ability of prosthetic feet to adapt to cross slopes and derive a theoretical model. Study design: Mechanical testing and characterization. Methods: Mechanical adaptation to cross slopes was investigated for six prosthetic feet measured by a motion capture system. A theoretical model linking the measured data with adaptations is proposed. Results: The type and degree of adaptation depends on the foot design, for example, stiffness, split toe or continuous carbon forefoot, and additional ankle joint. The model used shows high correlations with the measured data for all feet. Conclusions: The ability of prosthetic feet to adapt to uneven ground is design-dependent. The split-toe feet adapted better to cross slopes than those with continuous carbon forefeet. Joints enhance this further by allowing for additional inversion and eversion. The influence on biomechanical and clinical parameters should be assessed in future studies. Clinical relevance: Knowing foot-specific ability to adapt to uneven ground may help in selecting an appropriate prosthetic foot for persons with a lower limb amputation. Faster and more comprehensive adaptations to uneven ground may lower the need for compensations and therefore increase user safety.},

keywords = {arm prosthesis, arthrodesis, article, Axtion, biomechanics, bone conduction, finite element analysis, forefoot, histology, human, joint function, mathematical model, motion analysis system, osteoarthritis, Pacifica LP, Pro Flex LP, Prototype ESRJ, subtalar joint, theoretical model, Triton LP},

pubstate = {published},

tppubtype = {article}

}

@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 = {1E90 Sprinter, article, biomechanics, body weight, Cheetah Xtreme, comparative study, controlled study, female, finite element analysis, Flex-foot Cheetah, foot prosthesis, force, gait, human, human experiment, mechanical torsion, rigidity, simulation, Vari-flex Modular},

pubstate = {published},

tppubtype = {article}

}