Rethinking Ankle-Foot Orthosis Design: Feasibility Study of a Flexible AFO

IntroductionAnkle-foot orthoses (AFOs) are devices used to control the position and motion of the ankle and foot, so a safe and more efficient gait pattern results for people with lower-limb dysfunction. To provide the ankle and foot control, an AFO is typically made of hard plastic material. Research has shown that discomfort, difficulty using the device, or perceived lack of walking improvement results in low adherence to AFO use. The purpose of this study was to investigate an AFO made of a more flexible material to see if these drawbacks are improved.MethodsParticipants with a wide range of neurologic and musculoskeletal pathologies were issued a flexible AFO (FAFO). Performance and satisfaction data were collected at baseline, 2-week, and 3-month time points. Data collection included measures of balance (Berg Balance Scale) and temporal and spatial gait parameters (collected via the GAITRite Walkway System). Walking endurance was measured with the 6-minute walk test. Patient satisfaction was investigated using the Orthotic and Prosthetic User Satisfaction Survey (OPUS). Wearing adherence was measured as a percentage of the number of hours of wearing the FAFO per day.ResultsStatistical analysis using a paired t-test showed improvement was found from baseline to 2 weeks for balance and gait parameters of normalized velocity, double-limb support, and the Functional Ambulation Profile. These improvements were maintained at the 3-month follow-up. No improvement was found in patient satisfaction or walking endurance. Wearing adherence (number of hours per day) was found to be at the highest level of traditional AFO adherence-reported prior research.ConclusionsThis study found sufficient evidence to indicate the FAFO may be a feasible alternative to traditional hard material AFOs. Experimental trials comparing the FAFO to known gait improvements of currently accepted/traditional AFOs are needed.Clinical RelevanceThe FAFO investigated in this study provides beginning support for the feasibility of using ethylene-vinyl acetate thermoplastic as the sole material (coupled with the FAFO strapping system) for manufacturing an AFO. If further investigation confirms our findings, the FAFO can provide patients and orthotists another option to materials currently used in the manufacturing of an AFO.