TPress

@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{Beck2016,

title = {Characterizing the mechanical properties of running-specific prostheses},

author = {O. N. Beck and P. Taboga and A. M. Grabowski},

url = {https://www.embase.com/search/results?subaction=viewrecord&id=L613668924&from=export},

doi = {10.1371/journal.pone.0168298},

issn = {1932-6203},

year  = {2016},

date = {2016-01-01},

journal = {PLoS ONE},

volume = {11},

number = {12},

abstract = {The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.},

keywords = {1E90 Sprinter, adult, amputation, article, athlete, body mass, Catapult FX6, Cheetah Xtend, clinical article, controlled study, female, Flex-Run, foot prosthesis, human, hysteresis, male, materials testing, mechanics, prosthesis design, prosthesis material, prosthetic force displacement, prosthetic height, prosthetic stiffness, running, running specific prosthesis, Sprinter, transtibial amputation},

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{Beck2016,

title = {Characterizing the mechanical properties of running-specific prostheses},

author = {O. N. Beck and P. Taboga and A. M. Grabowski},

url = {https://www.embase.com/search/results?subaction=viewrecord&id=L613668924&from=export},

doi = {10.1371/journal.pone.0168298},

issn = {1932-6203},

year  = {2016},

date = {2016-01-01},

journal = {PLoS ONE},

volume = {11},

number = {12},

abstract = {The mechanical stiffness of running-specific prostheses likely affects the functional abilities of athletes with leg amputations. However, each prosthetic manufacturer recommends prostheses based on subjective stiffness categories rather than performance based metrics. The actual mechanical stiffness values of running-specific prostheses (i.e. kN/m) are unknown. Consequently, we sought to characterize and disseminate the stiffness values of running-specific prostheses so that researchers, clinicians, and athletes can objectively evaluate prosthetic function. We characterized the stiffness values of 55 running-specific prostheses across various models, stiffness categories, and heights using forces and angles representative of those measured from athletes with transtibial amputations during running. Characterizing prosthetic force-displacement profiles with a 2nd degree polynomial explained 4.4% more of the variance than a linear function (p<0.001). The prosthetic stiffness values of manufacturer recommended stiffness categories varied between prosthetic models (p<0.001). Also, prosthetic stiffness was 10% to 39% less at angles typical of running 3 m/s and 6 m/s (10?-25?) compared to neutral (0?) (p<0.001). Furthermore, prosthetic stiffness was inversely related to height in J-shaped (p<0.001), but not C-shaped, prostheses. Running-specific prostheses should be tested under the demands of the respective activity in order to derive relevant characterizations of stiffness and function. In all, our results indicate that when athletes with leg amputations alter prosthetic model, height, and/ or sagittal plane alignment, their prosthetic stiffness profiles also change; therefore variations in comfort, performance, etc. may be indirectly due to altered stiffness.},

keywords = {1E90 Sprinter, adult, amputation, article, athlete, body mass, Catapult FX6, Cheetah Xtend, clinical article, controlled study, female, Flex-Run, foot prosthesis, human, hysteresis, male, materials testing, mechanics, prosthesis design, prosthesis material, prosthetic force displacement, prosthetic height, prosthetic stiffness, running, running specific prosthesis, Sprinter, transtibial amputation},

pubstate = {published},

tppubtype = {article}

}