Image courtesy of Harrison Bartlett, PhD, Little Room Innovations, Ann Arbor, MI, via Twitter.
A team from Northeastern University, Boston, has designed a passive prosthetic ankle that lifts the toe during swing phase (to reduce falls) while providing full stance phase energy storage and return. The ankle recycles energy captured at heel strike to lift the toe during the next swing phase. It uses a novel linkage mechanism that locks the ankle during stance phase, allowing the foot to store and release energy. The mechanism works by moving a remote center of rotation (red dot in figure) to lock the joint during stance phase and dorsiflex the ankle in swing phase. A small compression spring dorsiflexes the ankle in swing. The ankle improved foot clearance by 13mm, which is enough to make a clinically significant difference in the number of falls experienced by real-world users.
