Project TitleAdaptable Ankle-Foot Prosthesis
Track Code2006-132, 2010-040, 2011-008
Short Description

Prosthetic and Orthotic Ankle-Foot Device, adaptable to changing grades & heel heights

#medicaldevice #prosthetics/rehabilitation


Northwestern researchers have designed several prototypes that significantly improve upon currently available passive ankle-foot prostheses. Their invention automatically adapts to different surface slopes and to shoes of different heel heights without electrical or active components. The Adaptable Ankle-Foot Prosthesis utilizes stiffness properties that mimic the natural behavior of an able-bodied foot and ankle for normal self-selected walking speeds. It sets its effective alignment in early stance phase, adapting automatically to surface slopes, and plantarflexes beyond a neutral position during the unloading phase of gait. After toe off, it brings the ankle back into a neutral or slightly dorsiflexed position to provide toe clearance during the swing phase. The ability of the system to store and release energy from a plantarflexed position should increase the return of stored energy to the leg, and thereby reduce the amount of energy needed for walking. This feature may in turn help prosthesis and orthosis users to walk at consistently faster speeds. Lastly, the ability of the ankle to adapt its alignment automatically to surface slopes should improve the stability of prosthesis and orthosis users, providing safer and more enjoyable ambulation on uneven terrain.

TagsMEDICAL DEVICE: prosthetics/rehabilitation
Posted DateApr 12, 2011 12:39 PM


Dudley Childress
Steven Gard
Andrew Hansen*
Eric Nickel
Brian Ruhe
Jon Sensinger

Ryan Williams


  • Ankle and Foot Prosthesis
  • Ankle and Foot Orthosis


  • Simple design without electrical or active components
  • Existing designs and constructed prototypes
  • Automatically adapts to changing slopes
  • Automatically adapts to different heel heights
  • May enable faster walking and reduce the amount of energy needed for walking


IP Status

Issued U.S. Patents:

Contact Information

Dimitra Georganopoulou, PhD

Invention Manager

(p) 847-467-3095