Biomechanical evaluation over level ground walking of user-specific prosthetic feet designed using the lower leg trajectory error framework

Abstract

The walking pattern and comfort of a person with lower limb amputation are determined by the prosthetic foot’s diverse set of mechanical characteristics. However, most design methodologies are iterative and focus on individual parameters, preventing a holistic design of prosthetic feet for a user’s body size and walking preferences. Here we refined and evaluated the lower leg trajectory error (LLTE) framework, a novel quantitative and predictive design methodology that optimizes the mechanical function of a user’s prosthesis to encourage gait dynamics that match their body size and desired walking pattern. Five people with unilateral below-knee amputation walked over-ground at self-selected speeds using an LLTE-optimized foot made of Nylon 6/6, their daily-use foot, and a standardized commercial energy storage and return (ESR) foot. Using the LLTE feet, target able-bodied kinematics and kinetics were replicated to within 5.2% and 13.9%, respectively, 13.5% closer than with the commercial ESR foot. Additionally, energy return and center of mass propulsion work were 46% and 34% greater compared to the other two prostheses, which could lead to reduced walking effort. Similarly, peak limb loading and flexion moment on the intact leg were reduced by an average of 13.1%, lowering risk of long-term injuries. LLTE-feet were preferred over the commercial ESR foot across all users and preferred over the daily-use feet by two participants. These results suggest that the LLTE framework could be used to design customized, high performance ESR prostheses using low-cost Nylon 6/6 material. More studies with large sample size are warranted for further verification.

A passive dorsiflexing ankle prosthesis to increase minimum foot clearance during swing

“…During stance phase, the effective point of application of the ground reaction force progresses anteriorly toward the toe, and it will eventually create an external dorsiflexion moment about the ankle joint ( ) (Gregg et al, 2014 ; Prost et al, 2022 ). At the same time, however, the net force that is parallel with the prismatic axis ( ) tends to compress the mechanism (due to the presence of a generally vertical ground reaction force).…”

“…Alternatively, this assumption will be satisfied if both and are between 0 and . This second assumption is generally true of human gait data during the middle and late stance phase of walking (Prost et al, 2022 ).…”

Finding a Natural Fit: A Thematic Analysis of Amputees’ Prosthesis Setting Preferences during User-Guided Auto-Tuning

“…Although the ultimate goal of prosthesis design is to help amputees to regain the locomotion functionality as non- disabled people (Prost et al, 2022; Schlafly & Reed 2020), amputees’ gait is different from the non-disabled individuals due to the technical limitations of existing prostheses. To regain daily functioning, amputees developed different compensation strategies, for example, in gait termination (Vrieling et al, 2008) and obstacle crossing (Vrieling et al, 2007).…”

Research of the dynamical properties of mechatronic prosthesis

“…and dynamics -the rate at which all preferable movement is reached [13]. Although the new development of active control implementation to the overall walking cycle was seen as a high improvement, the consequence of reducing the kinematic capabilities was introduced due to the complexity and the nature of the movement in the investigated joint [14], [15]. A need for complex design decisions reduced the level of a structure to meet its initial goal -to help regain the lost movement of the amputee.…”