Resistant, adjustable AFOs could be beneficial to orthotic users

NEW ORLEANS — Plantarflexion resistance of articulated ankle-foot orthoses significantly influenced ankle and knee joint kinematics and kinetics, according to data presented at the American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium, here.

Toshiki Kobayashi, PhD, research scientist at Orthocare Innovations, conducted a study of 10 patients with chronic stroke. Mean age was 56 years and the average time since last stroke was 6 years. Each patient was secured in a harness and walked on a split belt, fully instrumented treadmill while using an experimental ankle-foot orthosis (AFO).


Toshiki Kobayashi


The experimental AFO used steel rings to provide sufficient resistance to prevent drop foot, and used medial and lateral stability at the foot and ankle. It also adjusted the position of the ankle and brace to optimize knee stability.

Gait was analyzed using the Vicon Nexus 3-D motion system. Gait parameters included ankle angle at initial contact, peak ankle plantarflexion angle, peak ankle dorsiflexion moment and ankle moment zero-cross point. Parameters for the knee included initial joint angle in the first rocker of stance, peak knee extension angle and peak knee flexion moment in the second rocker of stance.

Findings showed that each ankle and joint parameter generally demonstrated a systematic response with use of the experimental AFO. The researchers also found that knee joint flexion and extension may be tuned by adjusting plantarflexion resistance of AFOs.

“Future studies should investigate how kinematic and kinetic data can contribute to better orthotic care,” Kobayashi said. “The development of more resistance tunable AFOs should be explored.” – by Shawn M. Carter


Kobayashi T. Paper F18. Presented at: American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium; Feb. 18-21, 2015; New Orleans.

Disclosure: This study was supported by the NIH and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Grant number 2R44HD069095.



Leave a Reply

Your email address will not be published.