Prototyping and evaluation of adaptability of a soft plastic T-strap for ankle-foot orthosis

[Purpose] We previously confirmed that a plastic ankle-foot orthosis with a joint having a built-in T-strap could correct ankle joint supination in able-bodied participants during stance phase without initial contact. In the present study, we examined the adaptability of a newly prototyped T-strap made of soft thermoplastic resin (plastic ankle-foot orthosis T-strap) by evaluating the pressure exerted on the center of the lateral malleolus. These results were compared to results obtained with a conventionally used leather T-strap. [Participants and Methods] We compared the pressure exerted on the center of the lateral malleolus by the plastic ankle-foot orthosis T-strap and a leather T-strap on one leg of each of eight able-bodied participants. Each leg was cast to fabricate eight custom ankle-foot orthoses. [Results] The applied pressure was significantly reduced with the plastic ankle-foot orthosis T-strap than that with the leather T-strap in all three phases-loading response, mid-stance, and terminal stance. [Conclusion] The plastic ankle-foot orthosis T-strap displayed better adaptability than did the leather T-strap. The tested plastic ankle-foot orthosis T-strap may be used as a more reliable alternative to a conventional leather T-strap.