Use this test to help you determine if you need orthotics.
All you need are a marking pen and a piece of 3″x5″ card stock. With the patient sitting comfortably (feet on the floor, but non?weightbearing), palpate the medial aspect of each foot and find the navicular prominence (the most prominent bony landmark found inferior and somewhat anterior to the medial malleolus). Using the pen, make a mark on the patient’s skin at the point of the navicular prominence. Stand the card on the floor next to the medial arch of the foot and mark the card at the level of the navicular prominence.
Next, ask the patient to stand, in a relaxed position. Once the arch is weightbearing, the navicular prominence will be somewhat lower. Make a second mark on the same side of the card at the new level of the navicular prominence. Repeat this procedure with the other foot.
Now measure the difference between the two marks for each foot.
If there is a drop of 4 mm. or more in the arch between sitting and standing, or if there is an obvious asymmetry from left to right, this is objective evidence of a functional foot problem ?? hyperpronation/collapse of the medial arch. This condition is best treated with flexible orthotics designed to be worn during all weightbearing activities.