Following transfemoral amputation, regaining functional mobility, particularly the ability to navigate curbs, ramps, long distances, and the ability to stand is challenging and often unattainable. Use of advanced prosthetic limb technology can dramatically influence mobility outcomes. The purpose of this study is to compare walking function in individuals with transfemoral amputations who are current users of the C-leg (current clinical standard) to function achieved when using the Bio Leg powered micro-processor prosthetic knee.
Although microprocessor-controlled knees (MPKs) such as the C-Leg have demonstrated clear benefits over non-microprocessor-controlled prosthetic knees, it remains unclear whether powered knee assistance provides additional advantages in movement quality, metabolic efficiency, and limb loading during walking adaptability tasks. This study directly addresses this gap by comparing mobility using the Bio Leg to mobility with the C-Leg using outcome measures that reflect real-world mobility challenges. By generating objective evidence on whether powered knee assistance improves biomechanics, efficiency, and stability beyond that achieved with an established MPK, this study will inform prosthetic prescription, rehabilitation strategies, and payer decision-making. Given the growing population of individuals living with transfemoral amputation, identifying technologies that support safe, efficient, and confident mobility has important implications for community participation, long-term musculoskeletal health, and quality of life. This study uses a within-subject repeated-measures design in which each participant is assessed under two conditions: current prosthesis and the Bio Leg prosthesis. All primary and secondary outcomes will be analyzed as within-participant differences, with each participant serving as their own control.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
After completing biomechanics and clinical testing at Pre Assessment with their C-Leg, participants will be fitted with a Bio-Leg prosthesis at the prosthetist clinic. The participant will train and use the Bio-Leg prosthesis during a 4-6 week acclimation period. The participant will then complete the same biomechanics and clinical testing at Post Assessment.
Brooks Rehabilitation
Jacksonville, Florida, United States
Change in 6-Minute Walk Test (6MWT)
The distance that a patient should walk based on their height, weight, age, and gender. Performance assessment of walking endurance for 6 minutes. An increase in the number of meters walked during this assessment reflects an improvement in walking endurance.
Time frame: Baseline, 4-6 weeks
Change in Interlimb Symmetry (Ground Reaction Forces)
A direct measure of vertical ground reaction forces during the rising phase of a sit-to-stand task (measured in Newtons) using standard force plates embedded in the floor. Increased symmetry in ground reaction forces between the lower limbs reflects improved equalization of weight distribution between the limbs.
Time frame: Baseline, 4-6 weeks
Change in Metabolic Efficiency (O2/kg/m)
A direct measure assessed during the six-minute walk test. Metabolic efficiency is determined by the energy cost of transport, defined as oxygen consumption per unit body weight and distance walked (O₂/kg/m), which accounts for the individual's weight and walking speed. Improved metabolic efficiency reflects enhanced oxygen delivery and utilization during walking.
Time frame: Baseline, 4-6 weeks
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