Impact of Powered Knee-Ankle Prosthesis Leg on Everyday Community Mobility and Social Interaction

The overall goal of this research is to determine the efficacy of new powered prosthetic devices for individuals with transfemoral amputations. The anticipation is that this will be a high-impact technological intervention with the potential to restore significant functionality to individuals with lower limb amputation and transform the field of lower limb prosthetics. The objective of the proposed clinical trial is to fully evaluate the biomechanical and energetic effects of using PKA prosthesis and quantify functional performance and quality of life changes.

The overall goal of this research is to bring powered devices, with suitable advanced control systems, to the clinic and home. The anticipation is that this will be a high-impact technological intervention with the potential to restore significant functionality to individuals with lower limb amputation and transform the field of lower limb prosthetics. The objective of the proposed clinical trial is to fully evaluate the biomechanical and energetic effects of using a powered knee-ankle prosthesis, identify task-specific training strategies for every-day device use, and quantify functional performance and quality of life changes at home and in the community. The hypothesis is that the powered knee-ankle prosthesis will demonstrate a significant improvement in function over existing technology. Furthermore, the hypothesis is that incorporating neural control information will provide enhanced, intuitive control of this device. Thus the approach is to directly compare the powered device with current state-of-art passive microprocessor controlled (MP) prostheses using a randomized cross-over study to control for subject-specific variation. 1.1 Aim 1: Perform in-laboratory training and testing to compare gait biomechanics and clinical performance over several ambulation modes using either a passive prosthesis or a powered prosthesis. The expectation is the PKA prosthesis to enable gait kinetics and kinematics that more closely resemble those of individuals with intact limbs, therefore lowering the biomechanical and metabolic effects of ambulation. 1.2 Aim 2: Perform home trials to evaluate community mobility and social interaction when using a powered knee-ankle prosthesis or a passive device. The expectation is that participants will choose to complete more diverse functional, occupational, and recreational activities when using the PKA prosthesis. 1.3 Aim 3: Quantify performance with the PKA device when using a novel intent recognition algorithm that allows for seamless transitioning between activities compared to a standard control method. The expectation is that pattern recognition- based control will further improve mobility and decrease the physiological costs of ambulation compared to using the standard control method.

Inclusion Criteria: * Unilateral transfemoral level limb loss or limb difference * K2/K3/K4 level ambulators * Required to use a microprocessor knee on their prosthesis Exclusion Criteria: * Over 250 lbs body weight * Inactive, physically unfit * Cognitive deficits or visual impairment that would impair their ability to give informed consent or to follow simple instructions during the experiments * Pregnant women * Co-morbidity that interferes with the study (e.g. stroke, pace maker placement, severe ischemia cardiac disease, etc.)