If you have been told you have flat feet, you have probably heard the same advice: get arch supports, wear motion-control shoes, stretch your calves. For some people, this is enough. For many others, the arch continues to collapse, the foot aches, and the rest of the body — knees, hips, lower back — eventually joins in.

If you have rolled the same ankle more times than you can count, you already know the strange loneliness of it. The sprain heals, the swelling fades, people assume you are fine, and then a curb, a gravel path, or a misjudged step sends you down again.

If you are reading this, there is a good chance you have felt it: a stiff, deep ache in the middle or back of the foot that shows up after sport, long walks, or a day on your feet — and an ankle that seems to "give way" more often than it should.

If you're dealing with a nagging, deep ache at the back-outer corner of your ankle that flares with pointed-toe positions, downhill running, or pushing off hard, you've probably already heard the standard advice: rest, ice, maybe a cortisone injection, maybe surgery if it doesn't settle.