Functional Performance Outcomes of a Powered Knee-Ankle Prosthesis in Service Members With Unilateral Transfemoral Limb Loss.

INTRODUCTION: Clinical knowledge surrounding functional outcomes of a powered knee-ankle (PKA) device is limited, particularly among younger and active populations with limb loss. Here, three service members (SM) with unilateral transfemoral limb loss received an optimally tuned PKA prosthesis and device-specific training. MATERIALS AND METHODS: Once proficiency with the PKA device was demonstrated on benchmark activities, and outcomes with the PKA and standard-of-care (SoC) prostheses were obtained via a modified graded treadmill test, 6-minute walk test, and overground gait assessment. RESULTS: All SM demonstrated proficiency with the PKA prosthesis within the minimum three training sessions. With the PKA versus SoC prosthesis, cost of transport during the modified graded treadmill test was 4.0% ± 5.2% lower at slower speeds (i.e., 0.6-1.2 m/s), but 7.0% ± 5.1% greater at the faster walking speeds (i.e., ≥1.4 m/s). For the 6-minute walk test, SM walked 83.9 ± 13.2 m shorter with the PKA versus SoC prosthesis. From the overground gait assessment, SM walked with 20.6% ± 10.5% greater trunk lateral flexion and 31.8% ± 12.8% greater trunk axial rotation ranges of motion, with the PKA versus SoC prosthesis. CONCLUSIONS: Compared to prior work with the PKA in a civilian cohort, although SM demonstrated faster device proficiency (3 versus 12 sessions), SM walked with greater compensatory motions compared to their SoC prostheses (contrary to the civilian cohort). As such, it is important to understand patient-specific factors among various populations with limb loss for optimizing device-specific training and setting functional goals for occupational and/or community reintegration, as well as reducing the risk for secondary complications over the long term.

Toward improving residual limb climate within prostheses for persons with lower limb loss: a technical note.

BACKGROUND: Individuals with lower limb loss often wear a gel liner and enclosed socket for connecting to a terminal prosthetic device. Historically, a significant limitation to traditional liners and sockets is that they are thermal insulators, thereby trapping heat and moisture within, which can lead to numerous deleterious issues, including loss of suspension and residual limb skin problems, and, in turn, reductions in mobility, function, and overall quality of life. To mitigate these issues, new approaches are therefore needed to enhance the residual limb climate (e.g. breathability and air permeability), allowing the dispersal of heat and moisture from within the liner and socket. METHODS: In this study, a multidisciplinary team sought to establish the feasibility of an innovative prosthetic liner-socket system, designed to improve residual limb climate by capitalizing on passive (i.e. nonpowered) ventilation to reduce temperature/moisture and improve socket comfort for persons with transtibial amputations. Focus group meetings, along with an iterative design approach, were implemented to establish innovative design and development concepts that led to a passively ventilated liner-socket system. CONCLUSIONS: Ex vivo design has supported the feasibility of developing a passively ventilated liner-socket. To build on these successes, future development and human subjects testing are needed to finalize a commercially viable system. Implementing a passively ventilated liner-socket system that improves residual limb health and comfort, without compromising function or mobility of the user, into standard clinical care may encourage a more active lifestyle and enhance the quality of life for individuals after lower limb loss.