HOW REPRODUCIBLE ARE THE EFFECTS OF A MICROPROCESSOR FOOT?

Abstract INTRODUCTION Using microprocessor-control to dynamically adapt hydraulic ankles, by changing the resistances to dorsiflexion and plantarflexion (DF/PF) movements, has been shown to have beneficial biomechanical effects during slope descent1. Another, more recent case study also showed that the level walking biomechanical effects of microprocessor-feet (MPF) persist, and the same trends can be observed in repeated gait analysis sessions, over a year apart2. This work looks to expand on both of these concepts, analysing repeated gait analysis sessions to see if the biomechanical changes of MPF during slope descent are reproducible over time. Abstract PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/32013/24432 How to cite: McGrath M, Stech N, Laszczak P, Kercher A, Zahedi S, Moser D. HOW REPRODUCIBLE ARE THE EFFECTS OF A MICROPROCESSOR FOOT? CANADIAN PROSTHETICS & ORTHOTICS JOURNAL, VOLUME 1, ISSUE 2, 2018; ABSTRACT, POSTER PRESENTATION AT THE AOPA’S 101ST NATIONAL ASSEMBLY, SEPT. 26-29, VANCOUVER, CANADA, 2018. DOI: https://doi.org/10.33137/cpoj.v1i2.3201

A Prosthetic Shank With Adaptable Torsion Stiffness and Foot Alignment

Torsion adapters in lower limb prostheses aim to increase comfort, mobility and health of users by allowing rotation in the transversal plane. A preliminary study with two transtibial amputees indicated correlations between torsional stiffness and foot alignment to increase comfort and stability of the user depending on the gait situation and velocity. This paper presents the design and proof-of-concept of an active, bio-inspired prosthetic shank adapter and a novel approach to create a user-specific human-machine interaction through adapting the device’s properties. To provide adequate support, load data and subjective feedback of subjects are recorded and analyzed regarding defined gait situations. The results are merged to an user individual preference-setting matrix to select optimal parameters for each gait situation and velocity. A control strategy is implemented to render the specified desired torsional stiffness and transversal foot alignment values to achieve situation-dependent adaptation based on the input of designed gait detection algorithms. The proposed parallel elastic drive train mimics the functions of bones and muscles in the human shank. It is designed to provide the desired physical human-machine interaction properties along with optimized actuator energy consumption. Following test bench verification, trials with five participants with lower limb amputation at different levels are performed for basic validation. The results suggest improved movement support in turning maneuvers. Subjective user feedback confirmed a noticeable reduction of load at the stump and improved ease of turning

Development of an integrated transfemoral prosthesis and an evaluation of control strategies for ramp descent.

Current microprocessor controlled prostheses for transfemoral amputees consist of two main functional components: a knee joint and an ankle-foot joint. These normally function as isolated joints without any feedback about the state of the other joint. In this research an approach investigating the system integration of the whole transfemoral limb has been undertaken. An integrated limb system was built based on two already existing but ‘stand-alone’ prosthetic joints by creating an appropriate control system and communication architecture. Two additional functionalities that require inter-joint communication were implemented: standing mode and ramp descent mode to support those challenging situations for transfemoral amputees. The development and biomechanical assessment of the ramp descent mode were undertaken to establish if integrated inter-joint control has the potential to change gait characteristics compared to non-integrated isolated single-joint control. Four different conditions (no braking, braking of foot, braking of knee and braking of the whole limb) were assessed trying to replicate non-integrated and integrated control in a systematic manner. The biomechanical assessment from the two amputee studies conducted revealed that braking of the whole limb showed the largest differences compared to the different conditions with some reaching statistical significance however the findings of the gait studies were inconsistent. There were some indications of increase of braking ratio, reduction in propulsive impulse and decrease of self-selected speed however not all results could be replicated. Overall this could indicate a more controlled ramp descent. Overall the research showed the potential of integrated coordinated transfemoral limb control and its benefits in one particular gait situation. For future work it is proposed to refine the ramp descent mode and focus on additional functionalities such as ramp ascent using the integrated approach. Integrating the socket and residual stump control into the integrated control system might provide a completely new approach of intuitive control

A prosthetic shank with adaptable torsion stiffness and foot alignment

Torsion adapters in lower limb prostheses aim to increase comfort, mobility and health of users by allowing rotation in the transversal plane. A preliminary study with two transtibial amputees indicated correlations between torsional stiffness and foot alignment to increase comfort and stability of the user depending on the gait situation and velocity. This paper presents the design and proof-of-concept of an active, bio-inspired prosthetic shank adapter and a novel approach to create a user-specific human-machine interaction through adapting the device's properties. To provide adequate support, load data and subjective feedback of subjects are recorded and analyzed regarding defined gait situations. The results are merged to an user individual preference-setting matrix to select optimal parameters for each gait situation and velocity. A control strategy is implemented to render the specified desired torsional stiffness and transversal foot alignment values to achieve situation-dependent adaptation based on the input of designed gait detection algorithms. The proposed parallel elastic drive train mimics the functions of bones and muscles in the human shank. It is designed to provide the desired physical human-machine interaction properties along with optimized actuator energy consumption. Following test bench verification, trials with five participants with lower limb amputation at different levels are performed for basic validation. The results suggest improved movement support in turning maneuvers. Subjective user feedback confirmed a noticeable reduction of load at the stump and improved ease of turning

BIOMECHANICAL ANALYSIS OF DIFFERENT PROSTHETIC TECHNOLOGIES FOR TRANS-FEMORAL AMPUTEES DURING SLOPE DESCENT

INTRODUCTION Lower limb amputees have different biomechanics to able-bodied people when walking on slopes1,2, often struggling to negotiate different gradients safely. Loss of proprioception and muscular control contributes to this issue, which is a particular problem for trans-femoral amputees, where both ankle and knee joints are absent. Studies have shown that prosthetic technologies can have benefits for slope negotiation. The aim of this study was to isolate the specific effects of different trans-femoral prosthetic technologies, by applying each additional mechanism incrementally. Abstract PDF  Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/32012/24431 How to cite: Stech N, McGrath M, Laszczak P, Kercher A, Zahedi S, Moser D. BIOMECHANICAL ANALYSIS OF DIFFERENT PROSTHETIC TECHNOLOGIES FOR TRANS-FEMORAL AMPUTEES DURING SLOPE DESCENT. CANADIAN PROSTHETICS & ORTHOTICS JOURNAL, VOLUME 1, ISSUE 2, 2018; ABSTRACT, POSTER PRESENTATION AT THE AOPA’S 101ST NATIONAL ASSEMBLY, SEPT. 26-29, VANCOUVER, CANADA, 2018. DOI: https://doi.org/10.33137/cpoj.v1i2.32012 Abstracts were Peer-reviewed by the AOPA 2018 National Assembly Scientific Committee

PERFORMANCE OF AN ACTIVITY MONITOR INTEGRATED INTO A MICROPROCESSOR KNEE

INTRODUCTION  For many years, the biomechanical evaluation of prosthetic performance has centred around gait analysis and motion capture. While this provides useful, scientific insights, everyday life is not limited to straight-line, level, steady-state walking. With advancements in portable sensor technology in the last two decades, long-term activity monitoring (AM) has become a more feasible and reliable prospect for accurately representing the real-world walking behaviour of patients. Modern microprocessor knees (MPKs) have begun to have this functionality built into the devices themselves, without the necessity for additional, external hardware. Abstract PDF  Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/32031/24448 How to cite: Sykes A, Stech N, Laszczak P, McGrath M, Kercher A, Zahedi S, Moser D. PERFORMANCE OF AN ACTIVITY MONITOR INTEGRATED INTO A MICROPROCESSOR KNEE. CANADIAN PROSTHETICS & ORTHOTICS JOURNAL, VOLUME 1, ISSUE 2, 2018; ABSTRACT, ORAL PRESENTATION AT THE AOPA’S 101ST NATIONAL ASSEMBLY, SEPT. 26-29, VANCOUVER, CANADA, 2018. DOI: https://doi.org/10.33137/cpoj.v1i2.32031             Abstracts were Peer-reviewed by the AOPA 2018 National Assembly Scientific Committee

PERFORMANCE OF AN ACTIVITY MONITOR INTEGRATED INTO A MICROPROCESSOR KNEE

INTRODUCTION  For many years, the biomechanical evaluation of prosthetic performance has centred around gait analysis and motion capture. While this provides useful, scientific insights, everyday life is not limited to straight-line, level, steady-state walking. With advancements in portable sensor technology in the last two decades, long-term activity monitoring (AM) has become a more feasible and reliable prospect for accurately representing the real-world walking behaviour of patients. Modern microprocessor knees (MPKs) have begun to have this functionality built into the devices themselves, without the necessity for additional, external hardware. Abstract PDF  Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/32031/24448 How to cite: Sykes A, Stech N, Laszczak P, McGrath M, Kercher A, Zahedi S, Moser D. PERFORMANCE OF AN ACTIVITY MONITOR INTEGRATED INTO A MICROPROCESSOR KNEE. CANADIAN PROSTHETICS & ORTHOTICS JOURNAL, VOLUME 1, ISSUE 2, 2018; ABSTRACT, ORAL PRESENTATION AT THE AOPA’S 101ST NATIONAL ASSEMBLY, SEPT. 26-29, VANCOUVER, CANADA, 2018. DOI: https://doi.org/10.33137/cpoj.v1i2.32031             Abstracts were Peer-reviewed by the American Orthotic Prosthetic Association (AOPA) 101st National Assembly Scientific Committee.  http://www.aopanet.org