There are various ways to treat this deformity from stents such as the hypocure to bone fusions, bone slides, reconstructions, etc.
Below are videos of a single arthrodesis to the triple arthrodesis. Arthrodesis or fusion is the mending or bringing together two or more bones. Set it and forget it as Ronco used to say. Fusions are typically for more advanced disease such as grade III or IV or if the patient is overweight with grade II disease.
Grade I : Tendonitis
Grade II: Tendonitis / Tearing
Grade III: Flexible adult flat foot
Grade IV: Rigid adult acquired flat foot