Knee instability is not always the result of a sports injury or a sudden fall. Sometimes the cause is something that has been building quietly over a long period of time. Flat feet and poor posture are two things most people wouldn’t think of when it comes to knee issues, but both can have a real impact on how stable the knee joint feels and functions over time.
How the Body Works as a Connected System
First, it is helpful to know that the body does not work in isolated parts before we get into flat feet and posture specifically. The way your foot sits on the ground will affect the way the force travels up through the ankle, into the knee, and further up into the hip and lower back.
When something is off at one level, it creates a compensating pattern somewhere else in the chain. The knee is often where that compensation shows up as pain or instability.
Flat Feet and the Knee
Here’s what you need to know about the impact of flat feet on your knees:
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Effect of Flat Feet on Your Alignment
Flat feet, also called pes planus, mean the arch of the foot has collapsed so that the entire sole makes contact with the ground. On their own, flat feet do not always cause problems. Many people have flat feet and never experience any discomfort.
But some people have a fallen arch that results in the foot rolling inward when they walk or stand, a movement called overpronation.
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Impact of Overpronation on the Knee
When the foot rolls inward excessively, it causes the shin bone to rotate inward as well. That internal rotation is transmitted directly to the knee joint. This creates uneven stress on the structures within and around the knee, such as the ligaments, cartilage, and the patella, which is the kneecap.
The kneecap in particular is sensitive to alignment. When the knee tracks slightly off course due to inward rotation from the foot, the kneecap can start to move in a way it was not designed to, which causes pain and a feeling of instability. This pattern is sometimes called patellofemoral syndrome, and flat feet are one of the contributing factors that can bring it on.
Poor Posture and the Knee
Poor posture and knee pain can be related in the following ways:
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How Posture Influences Knee Alignment
Posture is about more than how you hold your shoulders. It affects the alignment of your entire body from the head down to the feet. Two postural patterns in particular are closely linked to knee instability.
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Anterior Pelvic Tilt
An anterior pelvic tilt occurs when the pelvis is tilted forward excessively, deepening the lumbar curve and causing a rotation of the hips that changes the weight distribution through the lower limbs. This changes the angle of the knee and increases pressure on certain areas. Ligaments become strained, and the knee feels unstable over time.
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Weak Hips and Knee Collapse
Weak hip muscles, particularly the gluteus medius, which help to maintain the knee in correct alignment during movement, are often associated with poor posture. Weakness of the muscles of the hip causes a tendency of the knee to roll inwards with walking, running, squatting, or climbing stairs.
This repeated inward collapse stretches the ligaments on the outside of the knee and compresses the structures on the inside, leading to instability over time.
Wrapping Up
If you have been dealing with knee instability that does not have an obvious cause, like an injury, it is worth having an orthopedic evaluation that looks at the whole picture, including your foot alignment and movement patterns.
Consult our board-certified surgeon, Dr. Mufaddal Gombera, MD, for knee injuries. Call us today to book your appointment.
