Northwestern University Feinberg School of Medicine

Northwestern University Prosthetics-Orthotics Center

Pilot Study: Evaluation of Ankle Foot Orthoses (AFOs) Using Roll-over Shapes

Principal Investigator: Steven Gard, PhD

Co-Investigators: Dudley Childress, PhD; Andrew Hansen, PhD; and Rebecca Stine, MS, Northwestern University
Bryan Malas, CO, MHPE, Department of Orthotics, Children's Memorial Hospital

Stefania Fatone, PhD, Project Director

Funded by: National Institute on Disability and Rehabilitation Research (NIDRR)

Status: Completed


The purpose of this case series was to explore the effects of clinically prescribed ankle-foot orthoses (AFOs) (i.e., the orthosis an individual is provided by their health care team for everyday use) on the ankle-foot roll-over shapes (ROS) of persons with various pathologies. We hypothesized that persons for whom AFOs had been prescribed would have an abnormal ROS and that AFOs would make the ROS similar to that of able-bodied persons. Gait data were recorded from eight adults with unilateral involvement: five subjects (one with a common peroneal nerve injury, one with a subchondral talar cyst, one with an incomplete spinal cord injury, one with hemiplegia due to stroke, and one with postpolio) wore posterior leaf spring AFOs (PLS-AFOs); two subjects (with hemiplegia due to stroke) wore articulated AFOs with a plantar flexion stop and free dorsiflexion; and one subject (with hemiplegia due to stroke) wore a solid AFO. Participants walked with and without their AFO at their freely selected walking speed. "Normal" reference data were recorded from 10 able-bodied subjects of similar age walking at similar speeds. As hypothesized, ROS-as characterized by arc length and arc radius-was abnormal for all subjects when walking without an AFO. However, the prescribed AFOs were only able to partially restore ROS. Arc lengths were closer to normal with the AFO when compared to without, but changes in arc radius were less consistent, with only three subjects having radii that were closer to normal when the AFO was worn. Overall, there were smaller changes in ROS arc length and radius when PLS-AFOs were worn compared with articulated AFOs, consistent with the fact that PLS-AFOs are typically prescribed for those with less severe pathologies. ROS arc length and radius increased in all subjects with stroke when AFOs were worn. The results of this case series suggest that although clinically prescribed AFOs tend to improve ROS compared with walking without an AFO, they do not completely normalize it. Further research is required to assess the relationship between gait dysfunction, AFO design, and ROS.


This project has been completed. The results of this project are presented in the following publication:

Fatone S, Sorci E, Hansen A. (2009) Effects of Clinically Prescribed Ankle Foot Orthoses on Ankle-Foot Roll-Over Shapes: A Case Series. J Prosthet Orthot. 2009;21:196-203.

Related Publications

Sorci E, Fatone S, Hansen A, Gard S. (2007) Pilot Study Evaluating Ankle Foot Orthoses using Roll-over Shapes. Annual Meeting and Scientific Symposium of the American Academy of Orthotists and Prosthetists, March 21-24, San Francisco, California. (Resident Poster).