The risk factors for acquired flexible flatfoot secondary to PTT synovitis or rupture are Hypertension, diabetes
a history of trauma.
There are lots of other conditions which can lead to flat foot
Other conditions that can lead to flatfoot are:
Tight Achilles tendon, Neurologic diseases (e.g., poliomyelitis, spina bifida, myelodysplasia, NF, stroke), Osteoarthritis, posttraumatic arthritis, or inflammatory arthritis.