I have a bunion, a deformity related to the bone structure of my foot. Most people have big toes that stick out straight or slant gently in toward the other toes. The big toe on my left foot (the right one has been surgically corrected) juts in at an unacceptable forty-degree angle, jamming the smaller toes together. As tendons shrink further, the toe will wrap itself across the top of its neighbor and will be subjected to the surgeon's knife as well.

My angled toe has developed an ungainly bump on the side of the foot: my bunion. It rarely causes pain, but it does complicate shoe-buying. Shoe manufacturers, I have learned, do not tend to make shoes with large, ungainly bumps on the side. As a result, I must buy shoes too large for my right (surgically corrected) foot, and trust the bunion to impose its own shape on the left shoe. It usually does, at a price.

Since for nearly twenty years I've been a jogger, I have learned the sequence of my body's adaptation to shoes all too well. As I ...