Why Does Flatfoot Develop?
An Explanation from a Foot and Ankle Specialist (DPM)
As a foot and ankle specialist, one of the most common questions I hear from patients is:
“Why did I develop flat feet?”
Many people believe flatfoot is something they are simply born with.
However, in clinical practice, I see far more cases of
adult-acquired flatfoot than congenital flatfoot.
Flatfoot is not just a foot shape — it is often the result of
progressive changes in tendons, ligaments, and biomechanics over time.
What Is Flatfoot?
Flatfoot, also known as pes planus, occurs when the
medial arch of the foot collapses or becomes significantly lowered
during standing or walking.
Some patients have a visible arch when sitting, but the arch disappears
once they stand. This is known as flexible flatfoot,
the most common form seen in adults.
In other cases, the arch is absent even at rest, which may indicate
a more rigid or structural condition.
The Most Common Cause: Posterior Tibial Tendon Dysfunction
The posterior tibial tendon plays a critical role in
supporting the foot’s arch and stabilizing the ankle during walking.
With aging, overuse, or repetitive strain, this tendon can gradually
weaken or degenerate.
When this occurs, the arch can no longer be adequately supported,
leading to progressive collapse of the foot.
This condition is especially common in patients over the age of 50
and is a leading cause of adult-acquired flatfoot.
The Role of Aging and Weight Gain
As we age, the ligaments and tendons in the foot naturally lose
elasticity and strength.
At the same time, increased body weight places additional stress on
the arch-supporting structures.
Together, these factors can slowly change the shape of the foot,
even in individuals who previously had normal arches.
Many patients tell me,
“I never had flat feet when I was younger.”
This is a very common and medically explainable experience.
Footwear and Long-Term Mechanical Stress
Improper footwear can also contribute to the development of flatfoot.
Shoes that lack adequate arch support — such as worn-out sneakers,
flat shoes, or unsupportive sandals — allow the foot to
overpronate excessively.
Over time, this repetitive mechanical stress can accelerate arch
collapse and worsen symptoms.
Injury and Medical Conditions
Flatfoot may also develop following:
- Repeated ankle sprains
- Foot or ankle fractures
- Inflammatory arthritis, such as rheumatoid arthritis
- Diabetes-related nerve or tendon changes
In these cases, flatfoot is often associated with pain and functional
limitation and should be medically evaluated.
When Does Flatfoot Require Treatment?
Not all flat feet require intervention.
However, treatment is recommended when flatfoot is accompanied by:
- Pain along the inside of the ankle or foot
- Fatigue with prolonged standing or walking
- Changes in walking pattern
- Knee, hip, or lower back discomfort related to foot alignment
Flatfoot can affect the entire kinetic chain, not just the foot itself.
A Specialist’s Perspective on Management
Early recognition is key.
In many cases, custom orthotics, supportive footwear, and
targeted strengthening exercises can effectively reduce pain
and prevent progression.
Surgery is rarely the first option and is only considered when
conservative treatment fails.
Final Thoughts
Flatfoot is not simply a cosmetic concern — it is often a
biomechanical condition that develops gradually over time.
If you are experiencing discomfort or changes in foot shape,
seeking evaluation from a foot and ankle specialist can help prevent
long-term complications.
Your feet are the foundation of your body.
Taking care of them early can make a significant difference in your
long-term mobility and quality of life.
