STRESS-DISTRIBUTION IN THE ANKLE-FOOT ORTHOSIS USED TO CORRECT PATHOLOGICAL GAIT

Abnormal motion of the ankle-foot complex presents a major problem in the rehabilitation of stroke patients. These patients often develop dr op foot, a problem involving excessive and uncontrolled plantar flexio n. An ankle-foot orthosis (AFO) is prescribed to constrain and inhibit this abnormal motion. The purpose of this investigation was to simula te the drop foot problem to determine the stress distribution in the o rthosis. A quasi-static 3-D finite element analysis of the AFO complex was conducted using ADINA. Results confirmed the hypotheses that the maximum peak stress occurs in the neck, heel, and side-are region of t he AFO. However, the neck region of the AFO experienced the largest am ount of stress. High stress concentration in the neck region observed in the present analysis is consistent with the common clinical observa tion that AFOs break down in the neck region.