The rate of general foot problems among the elderly has been reported to be as high as 70-90%, and my experience certainly supports this. Many people develop deformities such as bunions, hammertoes, flat feet, corns, and extra bone growth. These can be painful problems in themselves, and can often lead to other issues.
A common question I hear in my office from patients experiencing these problems is, “why?” “Why are my toes curling under?” “Why are my feet flattening out?” It’s a sentiment that I can very much appreciate. There must be a reason for all of these foot problems, right?
As a doctor, I can try to explain to patients which tendons are tightening up and causing their hammertoes, or which tendons are getting weak and causing their feet to flatten out. We can usually pinpoint what the problem is, the immediate cause, but we often cannot adequately explain why it happened.
Occasionally, I will share my theory with a patient, as to why so many people experience these problems, and it goes back to something a professor of mine once said.
Most people are aware that our closest living relative is the Chimpanzee. DNA analysis has shown we share somewhere between 96-99% of the same genes. So, what makes us so unique?
The human brain is about three times the size of the chimps brain, and we have a much more developed cerebral cortex, but overall, the structure and function of our brains are almost identical to the chimps brain. I would argue, as my professor did, that the biggest difference in the anatomy of a chimp and a human is our feet.
The human foot performs a much different function than the foot of a chimpanzee, and therefore its structure is different. Our feet have only had about five millions years to evolve from the chimpanzee foot, only five million years to evolve a structure that supports a function that is very different than the function of the chimp’s foot. We can run marathons while they cannot. They can hang upside down from a tree limb with their toes, while we cannot. This tremendous difference in function, and the relatively short period of time that the human foot has had to adapt to these changing demands, is the reason we experience so many problems with our feet.
Compare this to a horse’s hoof, which has had about sixty million years to evolve. Sixty million years of gradual improvements to arrive at what we see today. The result is a foot, a hoof, that is highly specialized to perform a demanding job with minimal complications over the lifespan of the horse.
The consequence of these drastic changes in how our feet function when compared to our early ancestors, like chimps, is that our feet struggle to perform their new role, and that struggle is evident in the numerous deformities that people develop as they age.
Luckily, as doctors we can usually fix the problem, even if the “why” is more complicated to explain.
