Effects of ankle-foot prosthesis design on gait and standing performance in transfemoral prosthesis users: A scoping review.

Ankle-foot mechanisms are designed to substitute for missing anatomical behavior of lower-limb prosthesis users. Historically, the majority of ankle-foot mechanism research has been focused on transtibial prosthesis users despite evidence that current knowledge is not directly translated to transfemoral prosthesis users, such as the influence of single-axis knee alignment during gait and the differences in standing balance management. This review attempts to characterize the current state of published knowledge about the effects of ankle-foot prosthesis design on standing and walking performance in transfemoral prosthesis users. The databases of PubMed, Embase, Cochrane Library, CINAHL, and IEEE Xplore were searched on January 6, 2025. Data from the selected articles were extracted and reported following the PRISMA extension for scoping reviews. Thirty-five articles were included that reported on seven different types of feet, ranging from simple designs like a solid ankle-cushioned heel (SACH) foot to more complex ones such as a microprocessor foot. The range of reported study tasks extended from standing and level walking to more complex tasks like incline/decline slopes and parcourse walking. The results suggest some parallels between transfemoral and transtibial prosthesis users, such as improvements with the incorporation of roll-over-shape (ROS) features and adaptation of a hydraulic ankle. The literature also emphasized how ankle-foot components affect ground force vector position and direction, influencing prosthetic knee control, highlighting the importance of considering the interaction between the prosthetic ankle-foot and knee mechanisms. Understanding these interactions will support the development of clinical practice guidelines by identifying the pair of prosthetic components that maximizes performance.