With increasing temperatures outside, patients will ask for recommendations for sandals. Accordingly, you will want to teach your patients about proper sandal design and fit.
First and foremost, the more surface area contact there is between the foot and the sandal, the more support the foot will have. This means the wider the sandal and the higher the arch, the better the support as this will provide more of a foundation for the pronating foot.
The next consideration is stability. This is best accomplished by finding sandals that are adjustable as opposed to sliding on. Adjustable straps or Velcro fasteners are keys to a stable fit. All else being equal, wide straps are preferred to narrow straps.
Some of my favorite sandal manufactures include Chaco sandals, which tend to be wide, have a high arch and have fully adjustable straps that slide transversely to increase or decrease sagittal plane height. FitFlop sandals are also wide with a high arch in addition to a thick, cushioned midsole with wide upper straps. Orthaheel has a great selection of styles, many with adjustable straps, high arches and medium to wide profiles. Of course, Birkenstock has never left the playing field.
Although this list is far from comprehensive, recommending these brands can at least point your patients in the right direction and familiarize them with podiatry-approved features.
The American Podiatric Medical Association has a downloadable PDF on flip-flops, which you can print and give to your patients (see www.apma.org/flipfloptips  ). This PDF provides general tips for ensuring proper fit and is a great resource, which your patients will appreciate.