Biomechatronics | Shock Absorption and Interfacial Pressure
Massachusetts institute of technology, MIT, MIT Media Lab, robotics, prosthetics, prostheses, exoskeletons, orthoses, orthosis, science, engineering, biomechanics, mechatronics,
1211

Shock Absorption and Interfacial Pressure

About

Interfacial pressures at the human-machine interface can be a source of discomfort and potentially devastating tissue damage. These stresses may be reduced through a thorough understanding of the relevant biomechanics and interface design.

 

Effects of a powered ankle-foot prosthesis on kinetic loading of the contralateral limb: A case series

Lower extremity amputees encounter a series of stress related challenges. Among them is an increased risk of chronic joint disorders. For unilateral, transtibial amputees, we hypothesize that increasing the power output of the trailing, ankle-foot prosthesis during powered plantar flexion could mitigate kinetic loading applied to the leading, contralateral leg during walking. Here, we present a case series that analyzes kinetic factors of unilateral, transtibial amputee gait and forms a comparison between two types of ankle prostheses with varying power outputs. The factors examined here are impact resultant force, peak foot pressure at heel-strike, step to step transition work, and knee external adduction moment. The two prostheses are the amputee participant’s daily use passive ankle-foot prosthesis and the BiOM powered ankle-foot prosthesis
capable of biologically accurate powered plantar flexion during late stance. In a preliminary study on two transtibial amputees walking over level terrain at a controlled speed (1.25 m/s), we observed average reductions of 8% in peak impact resultant force, 18% in impact resultant force loading rate, 8% in peak heel-strike foot pressure, and 15% in the 1st peak knee external adduction moment when the powered ankle-foot prosthesis was compared to the conventional passive prosthesis. Overall, our preliminary results suggest that more biomimetic prosthetic ankle-foot push off during late stance may limit leading leg musculoskeletal stress in walking.