Flat Feet and Knee Pain: How Your Feet Affect Your Knees

Every step starts with the feet. They carry the whole body and pass the load on to the ankles, knees and hips. That is why the shape of the foot can play a role in how the knee feels. Flat feet are common, and many people with flat feet never have knee problems. In some people, however, the way the foot moves changes the load on the knee. This article explains the connection, how you can check your feet at home and what can help.

What flat feet are

With flat feet, the arch on the inner side of the foot is low or disappears when you stand. Two types are often distinguished. With a flexible flat foot, the arch is visible when you sit or stand on your toes and only flattens under body weight. This form is common and often causes no problems. With a rigid flat foot, the arch stays flat even without load. A rigid flat foot, or a foot that becomes noticeably flatter on one side only, should be checked by a doctor.

How the feet can affect the knees

When the arch flattens, the foot often rolls inward a little more with each step. The shinbone then turns slightly inward as well, and the knee can drift toward the midline. This changes how the load is spread across the knee, especially on the inner side and around the kneecap. In some people, this may contribute to pain over time. You can read more about these areas in our articles on pain on the inner side of the knee and runner's knee.

It is important to stay realistic: flat feet are only one of many factors. Muscle strength, body weight, activity, previous injuries and the condition of the joint usually matter just as much.

A simple self-check at home

• The footprint test: wet your feet and stand on a piece of dark paper or a dry tile. If almost the whole sole is visible and the inner curve is barely there, the arch is low.
• Your shoes: look at older shoes. If the heel and sole are clearly more worn on the inner side, the foot may roll inward.
• The mirror test: stand in front of a mirror and bend your knees slightly. If the knees move strongly toward each other, it is worth paying attention to foot and hip control.

This self-check does not replace an examination, but it gives you a first idea.

What can help

• shoes with good support around the heel and arch, rather than very soft or completely flat soles, as explained in our article on shoes for knee pain,
• arch-supporting insoles, which some people find helpful; if simple insoles are not enough, a specialist can advise on custom-made ones,
• exercises for the foot muscles, for example gathering a towel with your toes or slowly rising onto your toes and lowering again,
• regular calf stretching, because tight calves can increase inward rolling,
• strengthening the hip and buttock muscles, which help keep the knee in line,
• keeping an eye on body weight, which reduces the load on both feet and knees.

When to see a specialist

See a doctor if your feet or ankles hurt as well, if one foot suddenly becomes flatter, if the foot is stiff, or if the knee pain does not improve despite good shoes and exercise. An orthopedist or physiotherapist can assess your feet and the way you walk and recommend suitable insoles or exercises. Swelling, a knee that gives way or pain after an injury should always be checked.

Where a knee sleeve fits in

A knee sleeve works at the knee, not at the foot. It does not correct the position of the foot, but it can give the knee pleasant warmth and a sense of support on walks, on the stairs or during a long day on your feet. Many people combine good shoes, supportive insoles and a soft sleeve, so that each part does what it does best.

A sleeve you will actually wear

The best sleeve is the one that does not end up in a drawer. The KeenTrove Bamboo Knee Sleeve is made for exactly that:

• soft, breathable bamboo, comfortable even in summer
• fits snugly but does not dig in behind the knee
• does not lock the knee, so you move naturally
• wear it under your clothes during the day and in bed at night

With 60 days to get your money back, you have nothing to lose.

See the bamboo knee sleeve →

Note: this article is for information only and does not replace an examination by a doctor. If you have circulation problems or diabetes, or have recently had knee surgery, talk to your doctor before wearing compression.