Changes of Ankle Motion and Ground Reaction Force Using Elastic Neutral AFO in Neurological Patients with Inverted Foot During Gait

Many stroke patients develop ankle deformities due to neurological or non-neurological factors, resulting in abnormal gait patterns. While Ankle-Foot Orthoses (AFOs) are commonly used to address these issues, few are specifically designed for ankle varus. The Elastic Neutral Ankle-Foot Orthosis (EN-AFO) was developed for this purpose. This study aimed to analyze changes in kinematic and kinetic gait data in stroke patients with ankle varus, comparing those walking with and without EN-AFO in both AFO and No-AFO groups. Initially, 30 stroke patients with ankle varus were screened; after exclusions, 17 were included in the final analysis. In the No-AFO group, EN-AFO significantly improved maximal ankle inversion on the affected side during the swing phase (from 4.63 ± 13.26 to 10.56 ± 11.40, <i>p</i> = 0.025). Similarly, in the AFO group, EN-AFO led to a significant improvement in maximal ankle inversion on the less-affected side during the swing phase (from 7.95 ± 10.11 to 12.01 ± 8.64, <i>p</i> = 0.021). Additionally, ground reaction forces on the affected side of the AFO group significantly increased at both the forefoot (from 182.76 ± 61.45 to 211.55 ± 70.57, <i>p</i> = 0.038) and hindfoot (from 210.67 ± 107.88 to 231.85 ± 105.38, <i>p</i> = 0.038) with EN-AFO. Conversely, maximal and minimal thoracic axial rotation on the affected side improved significantly in the No-AFO group compared to the AFO group with EN-AFO, during both the stance and swing phases (stance phase: max improvement from −1.13 ± 1.80 to 4.83 ± 8.05, min improvement from −1.06 ± 2.45 to 5.89 ± 7.56; swing phase: max improvement from −1.33 ± 2.13 to 5.49 ± 7.82, min improvement from −1.24 ± 2.43 to 5.95 ± 7.12; max <i>p</i> = 0.034, min <i>p</i> = 0.016 during stance; max <i>p</i> = 0.027, min <i>p</i> = 0.012 during swing). Furthermore, both maximal and minimal thoracic axial rotation on the less-affected side during the swing phase improved significantly in the No-AFO group (max improvement from −2.09 ± 4.18 to 6.04 ± 6.90, min improvement from −0.47 ± 2.13 to 8.18 ± 10.45; max <i>p</i> = 0.027, min <i>p</i> = 0.012) compared with the AFO group. These findings suggest that EN-AFO may effectively improve gait in stroke patients with ankle varus in the No-AFO group.