Why Do Collapsed Feet Make My Knees and Back Hurt?

Key points in 30 seconds

1. Your feet are where your body first meets the ground.
2. When that first point tilts, the knees and pelvis tilt with it.
3. That tilt is repeated over more than 5,000 steps a day.
4. When your knee hurts, we look at your foot arches, your walking, and your pelvis height together.
5. However, if there's swelling or it started after an injury, other tests come first.

What we often hear

• "My feet hurt, and so do my knees and back."
• "This is the first time I've heard my feet might be the problem."
• "I don't know where to start looking."

Why do collapsed feet make my knees and back hurt?

Your feet are where your body first meets the ground. When that first point tilts, the knees and pelvis above it tilt too in order to keep balance, and walking in that tilted state is repeated thousands of times a day.

When people come in with knee pain and we say we'd like to look at their feet first, they're puzzled. But the knee is a joint caught between what's above and below it. If force is pushing up from below, the knee has no choice but to absorb it.

How many times a day does it repeat?

Adults in Korea take more than 5,000 steps a day on average. If your steps lean to one side, that tilt is repeated thousands of times every day.

There's a reason this number matters. The time we spend setting your posture in the clinic is a few dozen minutes at most. The thousands of steps you take the rest of the time undo it. This is why supporting the feet has to go along with treatment.

Starting from the feet, how far up does it go?

When the foot arch collapses, the shinbone rotates inward, the knee above it caves in, the pelvis sits at different heights on each side, and the lower back curves to one side to make up for it.

This is a pattern we often see in the clinic. The pelvis drops on the side where the foot has collapsed, and the opposite shoulder rises. One shoe heel wears down, and the zipper of your pants twists to the side. In most cases, the person has never thought their feet might be the problem.

So what do you check when my knee hurts?

We look at the height of your foot arches when standing, which part of the foot your weight passes through when walking, and the height of your pelvis on each side. We don't look only at the knee.

Checking isn't difficult. We look at the soles of the shoes you came in. Whether only the outer or only the inner edge of one shoe is worn is a record your walking has left. If calluses form in only one spot on the sole, that's a sign your weight passes through that spot alone.

What are the limits of this judgment?

We can't say for certain the feet are the cause. Knee and back pain have many other causes, and the feet are just one of them.

A few more points. First, many people have collapsed feet and feel perfectly fine. Being collapsed and being painful are different things. Second, this pattern is what we've seen in the clinic, not something confirmed with a comparison group. Third, if your knee is swollen or warm, or the pain started after an injury, other tests come first.

We look at where you meet the ground before the spot that hurts. When the feet collapse, the knees and pelvis above them follow one after another.

If treatment for your knees or back keeps wearing off, have your feet looked at. Sometimes searching only higher up misses the cause.

Even with the same foot shape, whether pain develops differs from person to person.