While I can’t give you a good answer, I can give you one based on lived experience with a knee that basically fell apart in a skateboarding accident.
If I’m standing in place, I now stand on the blade of my right foot because it relieves weight from the medial side of my knee preventing it from feeling like it’s buckling. If I roll my foot to the other side, suddenly the pressure is immense in that spot.
The arch of the foot alleviates weight on the knee joint by acting like a cushion and directly the leg upwards to the hip correctly. If your foot was flat the cushion wouldn’t exist and there would be more weight placed on your knees.
I have flat feet and developed accessory navicular bones (looks like a bump on the inner side of my feet.) Oftentimes it doesn’t bother me anymore unless I hit it on something it can be quite painful. I suffered more in my childhood when I had to walk/run more playing sports and whatnot but I never let it stop me from doing the things I enjoyed.
I get sole inserts made for my shoes from specialized podiatrists as any of the dr sholes I try make little to no difference in comfort.
There are surgical procedures for removal of the bone but I figure it would take a long time to recover. I have been advised it’s better to do the younger you are so I am still in consideration of it.
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