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

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.)