The Immediate Effect of Changing the Footplate Profile of a Rigid Ankle-Foot Orthosis (AFO) on Lower Limb Kinematics and User Feedback

Abstract

Background: Rigid ankle-foot orthoses (AFOs) are widely used within clinical practice to address pathological gait. A literature review search illustrated AFO footplate variations are under investigated, despite this being a key design feature in AFO prescription. There are currently no studies investigating how dorsiflexing the footplate would affect lower limb kinematics and user feedback. Objective: To evaluate the effects of dorsiflexing the footplate on hip, knee and ankle kinematics and user feedback. Study design: Feasibility study. Methods: Healthy participants (n = 10) were tested under four test conditions: shoe- only, rigid AFO with 0° of dorsiflexion at the footplate, rigid AFO with 15° of dorsiflexion at the footplate and rigid AFO with 30° of dorsiflexion at the footplate. Data on hip, knee and ankle kinematics was obtained from midstance to pre-swing. User feedback was established through verbal free text comments and scoring the visual analogue scale. Results: The most significant finding in this study is identifying 100% of the participants preferred a dorsiflexed footplate over a flat footplate. No statistically significant differences were observed; however, trends in hip, knee and ankle kinematics were identified. Conclusion: We recommend orthotists consider dorsiflexing the footplate of rigid AFOs as part of routine clinical practice. Further research is required to comprehend the effects of dorsiflexing the footplate on pathological gait and to determine a suitable prescription criterion.