Flat Feet and Knee Pain: How a Small Problem in the Foot Can Lead to a Big Problem in the Knee

1. Who Will Benefit From This Article?

If you’ve ever wondered why your knees hurt, even though you haven’t had a direct injury—or if you’ve been dealing with knee pain that seems to come and go for no clear reason—this article is for you. It’s especially helpful if you know or suspect you have flat feet (also called pes planus). You’ll learn how a seemingly small issue at the bottom of your body can have big consequences further up the chain. Whether you’re an active person, someone who’s on their feet a lot, or just trying to move through daily life without discomfort, keep reading.

2. How Common Is Knee Pain Among Adults?

Knee pain is extremely common—especially as we get older or spend more years doing repetitive motions like walking, standing, or even sitting with poor posture. In fact, knee pain affects about 1 in 4 adults at any given time. It’s one of the most frequent complaints in orthopedic and physical therapy clinics. And what many people don’t realize is that the pain often doesn’t start at the knee itself—it starts lower down, at the foot.

3. What Are the Functions of the Foot?

Our feet are true multitaskers. They do way more than just help us walk from point A to B. Here’s what healthy feet are built to do:

• Support your body weight
  
• Keep you balanced and stable
  
• Adapt to different surfaces
  
• Act like shock absorbers, especially when walking or running
  
• Push your body forward during movement
  
• Send feedback to the brain about the ground underneath, helping with coordination
  

All of these roles depend on one major structure: the arch of the foot. Think of the arch like a spring—it bends and rebounds, softening impact and then helping you push off again with each step. But when this arch collapses, as it does in flat feet, trouble begins.

4. The Broken Spring: Why Flat Feet Mess With Your Knees

Flat feet mean that the natural arch of the foot is either very low or completely collapsed. This messes up the foot’s ability to act like a spring. And when that spring fails, a chain reaction starts:

• Shock isn’t absorbed properly, so the impact from walking or running travels straight up to the knees.
  
• The foot often overpronates (rolls inward too much), which rotates the lower leg and puts the knee out of alignment.
  
• This misalignment increases stress on specific parts of the knee—especially the medial (inner) side.
  

The end result? A knee joint that takes way more of a beating than it’s built for. Over time, this can lead to chronic pain, inflammation, and even early osteoarthritis.

One study found that people with knee osteoarthritis and flat feet experienced worse symptoms, more stiffness, and faster degeneration compared to those with normal arches. So yes—it’s a big deal.

5. Which Soft Tissues Around the Knee Take the Most Damage?

Let’s zoom in on what’s actually getting irritated when flat feet lead to knee pain:

• Medial Collateral Ligament (MCL): Supports the inner part of the knee. Overpronation pulls this ligament into a stretched, strained position.
  
• Meniscus: Cartilage cushions between your thigh bone and shin. Misalignment can wear it down faster.
  
• Patellar Tendon: Connects the kneecap to the shin. Changes in walking mechanics can stress this tendon and cause pain just below the knee.
  
• Iliotibial (IT) Band: Runs along the outside of your leg. Altered gait from flat feet can irritate this band, causing pain on the outer knee.
  

All of these structures are built for movement—but they’re not built to take constant abnormal pressure. That’s what flat feet can cause.

6. What Should a Patient Do?

First, don’t ignore the pain. Just because it starts small doesn’t mean it won’t grow into something bigger.

If you suspect flat feet are affecting your knees, here’s what you should do:

• See a specialist, like a podiatrist, orthopedic doctor, or physical therapist.
  
• Get a foot assessment, ideally including a gait analysis.
  
• Use custom orthotics or shoe inserts to support your arches.
  
• Wear supportive shoes—avoid flat, unsupportive footwear like flip-flops or worn-out sneakers.
  
• Start a strengthening and stretching routine—a professional can guide you through the right ones.
  

7. What You Can Start Doing at Home

Even before you see a specialist, there are some things you can do right now to start relieving pressure on your knees:

✅ Toe Curls
Sit in a chair, lay a towel on the floor, and use your toes to scrunch it up toward you. This strengthens the arch.

✅ Heel Raises
Stand tall and slowly lift your heels off the ground. This activates muscles that support foot posture.

✅ Stretch Your Calves and Hamstrings
Tight muscles in the back of the leg can worsen flat feet and knee issues.

✅ Ice painful areas
If your knees hurt after a long day, 10–15 minutes of ice can help reduce inflammation.

✅ Watch your walking
Try to avoid walking barefoot on hard surfaces for long periods—wear supportive footwear even at home.

Final Thoughts

Flat feet might seem like a minor issue, but they can quietly wreak havoc on your knees over time. The good news? With the right steps, most people can manage or even eliminate this kind of knee pain—without surgery.

If your knees have been bothering you and nothing seems to help, it’s worth looking down at your feet. Fix the foundation, and the rest of the structure has a better chance of holding up.

Citations:

1. https://www.spectrumphysio.info/impact-of-flat-foot-on-hip-and-knee-pain/
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC9280043/
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC3087845/
4. https://acc.vn/en/flat-feet-knee-pain/
5. https://jocr.co.in/wp/2024/10/01/the-impact-of-pes-planus-on-knee-function-and-its-association-with-medial-compartment-knee-osteoarthritis/
6. https://sanderspodiatry.com.au/blog/2024/12/05/5-ways-the-feet-affect-the-knees/
7. https://my.clevelandclinic.org/health/diseases/flat-feet-pes-planus
8. https://onlinelibrary.wiley.com/doi/full/10.1002/jor.23565