Firstly, in Australia they
call “thongs” what the rest of the world call flip flops.
These
Archies Thongs that come from Australia are proving to be very popular with Podiatrists, a lot of them selling them in their clinics.

The arch support in these thongs is similar to what you get in an over-the-counter arch support or prefabricated foot orthotic so there is no reason why there can not be used as an alternative to a foot orthotic in some circumstances and as a useful adjunct to foot orthotic therapy.

They were designed by a physiotherapist in Australia.
For more, see this
video testimonial.