Metabolic effects of using a variable impedance prosthetic knee

Abstract

Abstract-A transfemoral amputation has a significant effect on walking. Though current prosthetic knee options serve to restore mobility, as purely passive devices, they do not fully restore nondisabled gait. Persons with transfemoral amputation incur a higher metabolic cost during walking than persons without amputation and as a result walk slower and for shorter distances before tiring. An original variable-impedance transmission prosthetic knee (VI Knee) was tested in five study participants with unilateral transfemoral amputation at two steadystate walking speeds, one below and one above their preferred walking speed. While walking with the VI Knee, participants with shorter limbs showed a reduction in metabolic cost compared with their conventional C-Leg prosthesis, while those with longer limbs exhibited an increase. Though differences were observed between speeds, overall the difference in metabolic cost (reduction or increase) was found to correlate significantly with rise in the center of mass, with those with shorter residual limbs exhibiting less overall lifting of the body during gait.

Quantifying Step Count and Oxygen Consumption with Portable Technology during the 2-Min Walk Test in People with Lower Limb Amputation

“…While these findings of metabolic and step data shed light on responses during a 2MWT, this information raises further questions when drawing comparisons to previous research. For example, the reason for limb loss [56], type of foot [57], or knee used [58], and prostheses mass [59] are additional variables to consider when drawing conclusions or categorizing performance while using tests such as the 2MWT.…”

Functional outcomes and user preferences of individuals with transfemoral amputations using two types of knee joints in under-resourced settings

“…5 Prosthetic knee function is particularly important in providing stability and enabling knee movements during gait. Prosthetic knee joints influence physiological and biomechanical performance including walking speed and efficiency, 6 gait patterns, 7 as well as function and quality-oflife outcomes. 8 In under-resourced environments, fewer than 15% of persons with LLA have access to prostheses 9 and where accessible, prostheses typically comprise basic technologies providing limited performance.…”

“…5 Prosthetic knee function is particularly important in providing stability and enabling knee movements during gait. Prosthetic knee joints influence physiological and biomechanical performance including walking speed and efficiency, 6 gait patterns, 7 as well as function and quality-of-life outcomes. 8…”

Biomechanical responses of young adults with unilateral transfemoral amputation using two types of mechanical stance control prosthetic knee joints

“…Stance control performance is critical as it aids in minimizing falls and related injuries, and promotes confidence and utilization of the prosthesis. 1 From a physiological perspective, selection of knee mechanisms is also seen to influence efficiency of gait, 2–4 and biomechanically have an effect on the gait-related movement and loading patterns which are commonly quantified in terms of spatiotemporal, kinematic, and kinetic measures.…”