What causes fallen arches in adults?
Adult-acquired flatfoot, medically known as posterior tibial tendon dysfunction (PTTD), represents a significant structural change where the foot’s arch progressively collapses. This isn’t like being born with flat feet – adult flatfoot happens later in life because of different reasons like injuries, wear and tear, or other health issues. Foot experts say adult flatfoot usually starts when your posterior tibial tendon stops working right – that’s the main tendon that holds up your arch. It’s really important to know what causes adult flatfoot so you can treat it properly and stop it from getting worse, especially since lots of people don’t get diagnosed until their arch is already pretty flat.
Table of Content
- Posterior Tibial Tendon Dysfunction and Degeneration
- Arthritic Conditions and Inflammatory Arthritis
- Traumatic Injuries and Structural Damage
- Neurological Conditions and Muscle Imbalance
- Systemic Diseases and Connective Tissue Disorders
- Iatrogenic Causes and Surgical Complications
- Frequently Asked Questions About Adult Flatfoot Causes
Posterior Tibial Tendon Dysfunction and Degeneration
Here’s how the main tendon problems happen
The posterior tibial tendon is your foot’s main arch supporter. When it wears out, that’s actually the most common reason adults develop flat feet. This important tendon starts in your calf, runs behind your inner ankle bone.
and connects to several foot bones. It gives your arch crucial support whenever you stand or walk. As Dr. James C. Sullivan from University of Chicago Medicine puts it, when this tendon gets swollen, overstretched.
or torn, it can’t hold up your arch properly anymore. That’s what causes the arch to gradually fall. The wearing down process usually happens from repeated small injuries that the tendon can’t keep up with repairing.
This damage builds up over months or years, causing inner ankle pain and your arch slowly dropping.
What puts you at risk for tendon problems
Several things can make this tendon fail. Getting older, carrying extra weight, and certain health conditions are the biggest contributors to posterior tibial tendon problems. Research studies have found these main risk factors:
| Risk Factor | How common in flatfoot patients | How it causes problems |
|---|---|---|
| High blood pressure | Shows up in 42-58% of cases | Reduces blood flow to the tendon |
| Diabetes | Affects 31-45% of patients | Damages the tendon’s building blocks |
| Obesity | Found in 67-72% of people | Puts extra stress on your arch |
| Past ankle injuries | Seen in 28-39% of cases | Changes how you walk and creates scar tissue |
| Steroid use | Present in 15-22% of patients | Weakens the tendon and slows healing |
Other conditions that set you up for problems include inflammatory arthritis like rheumatoid arthritis. Here, joint inflammation directly damages the tendon’s strength. Also, some people are born with extra foot bones like an accessory navicular. This can make stress spread unevenly across your foot, wearing down the tendon faster. This condition keeps getting worse over time, so catching it early makes a big difference. If you treat it in stage 1 when there’s just tendon swelling but no foot deformity yet, you’ll get much better results than waiting until your foot shape has permanently changed.
Arthritic Conditions and Inflammatory Arthritis
Rheumatoid Arthritis and Joint Destruction
Here’s how rheumatoid arthritis leads to flat feet: the inflammation in your joints damages the ligaments and cartilage that support your foot’s arch. RA creates abnormal tissue that eats away at important foot joints.
slowly breaking down the foundation that keeps your arch up. The European Foot and Ankle Society notes that approximately 90% of RA patients develop foot involvement.
with posterior tibial tendon dysfunction and midfoot collapse representing common late-stage manifestations. The inflammation weakens both the moving parts and the structural supports in your foot, especially the spring ligament, causing a double whammy that leads to serious flat foot deformities.
Osteoarthritis and Degenerative Joint Changes
Osteoarthritis is another big cause of flat feet in adults, where the cartilage wears down and joints in the midfoot get narrower, messing up your arch support.
When the joint surfaces break down, the bones can’t hold their proper position anymore, so your foot’s main arch starts to sag and collapse. A top foot surgeon points out that arthritis after foot fractures or Lisfranc injuries is especially tough.
often leading to flat feet that get worse quickly. As the joints keep breaking down, your weight shifts unevenly across your foot, putting strange pressures that speed up the damage and make your arch fall even more.
Traumatic Injuries and Structural Damage
Lisfranc Injuries and Midfoot Instability
Traumatic mechanisms: Lisfranc joint injuries are a serious trauma that can cause flat feet in adults, they mess up the transverse arch that keeps your midfoot stable.
These injuries usually happen when your foot gets twisted while pointing downward, like when you miss a step or in car crashes, and they damage the ligaments connecting your foot bones.
Doctors often miss about 20% of Lisfranc injuries at first, which means treatment gets delayed and your midfoot can gradually collapse, causing that typical flatfoot look.
This instability makes your forefoot splay outward and your arch drop down, creating a flat, turned-out foot that gets harder to treat without surgery over time.
Tendon Ruptures and Ligamentous Disruption
Acute structural failure: If you completely tear your posterior tibial tendon or spring ligaments, you can develop flat feet really quickly, usually after accidents like falls or bad ankle twists.
Unlike the slow wear-and-tear of PTTD, these sudden injuries mess up your foot mechanics right away, and people often feel a pop or tear, then quickly see their foot shape change.
Studies show that when both the posterior tibial tendon and spring ligament get injured together, the flatfoot deformity becomes much worse than if just one of them is damaged.
That’s why it’s so important to get a thorough checkup when trauma causes flat feet, since several parts might need fixing at once to get your foot back to normal.
Now let’s talk about how nerve problems and muscle imbalances can cause flat feet in adults.
One big cause is Charcot neuroarthropathy, which leads to serious arch collapse.
Charcot neuroarthropathy usually happens with diabetic nerve damage. It destroys nerves and makes your arch collapse completely. This occurs because your numb joints and bones keep getting tiny injuries over and over.
This is the most severe type of adult-acquired flatfoot. The bones in your midfoot gradually break down and fragment, creating a serious deformity. People often call this a rocker-bottom foot because of its curved shape.
The nerve damage affects both feeling and automatic body functions. The automatic nerve damage increases blood flow, which speeds up bone loss. Here’s how neuropathic flatfoot differs from the mechanical kind:
| What to look for | Charcot neuroarthropathy | Mechanical PTTD |
|---|---|---|
| How it starts | Comes on fast with swelling | Develops slowly over months or years |
| Pain level | Little pain even with bad deformity | Moderate to severe pain |
| Skin temperature | Much warmer than normal | Normal or a bit warm |
| Where it occurs | Usually midfoot (60% of cases) or hindfoot | Inner ankle and arch area |
| Main treatment | Limited weight-bearing with protection | Shoe inserts and physical therapy |
Another cause is nerve compression leading to weak muscles
Nerve compression issues like tarsal tunnel syndrome also cause adult flatfoot. When nerves get pinched, the small muscles inside your foot that support your arch become weak.
If your posterior tibial nerve gets squeezed in the tarsal tunnel, it stops working properly. This affects muscles like the abductor hallucis, flexor digitorum brevis, and quadratus plantae.
As Dr. Judith Baumhauer, an orthopedics professor, explains: when nerve compression continues, it starts a bad cycle. Muscles waste away, your foot mechanics change, and the arch structure weakens further, making collapse happen faster.
This nerve-related flatfoot doesn’t just change your foot’s shape. You might also feel burning pain or numbness. It’s complicated to treat, needing both nerve specialists and bone doctors to help.
Systemic Diseases and Connective Tissue Disorders
Marfan Syndrome and Ehlers-Danlos
Some inherited conditions really mess with your connective tissue. Marfan syndrome and Ehlers-Danlos syndrome are good examples – they cause flat feet in adults because your collagen doesn’t form right.
This weakens ligaments all over your body. What happens is you get super flexible joints and loose ligaments. They just can’t handle your body weight and gravity like they should.
So even if your muscles work fine, your arch slowly collapses over time. The National Organization for Rare Disorders points out something pretty striking – almost 80% of people with Marfan syndrome get serious flat feet.
This happens because of problems with fibrillin-1 that make your foot’s support system less springy and strong. Flat feet in these cases usually come with other body-wide issues too.
We’re talking super flexible joints, curved spines, and chest shape problems. All these signs together show it’s a whole-body connective tissue problem, not just a foot thing.
Collagen Vascular Diseases
Then there are autoimmune diseases that target your connective tissue. Conditions like lupus and scleroderma can cause flat feet you develop later in life.
They create this perfect storm of joint inflammation, tendon trouble, and tight tissues that totally change how your foot works. With lupus, constant joint inflammation wrecks the bones in your midfoot and below your ankle.
Plus, the inflammation often goes after that important posterior tibial tendon – the one that normally supports your arch. Scleroderma works differently – it causes scarring in your plantar fascia and other support tissues.
This makes everything too tight to move properly, so your foot compensates by collapsing in ways it shouldn’t. The Lupus Foundation of America reports that approximately 65% of SLE patients experience foot involvement.
with posterior tibial tendon dysfunction being a frequently overlooked contributor to disability. For these whole-body conditions, you really need a team approach.
Rheumatologists and foot doctors have to work together to tackle both the inflammation causing the trouble and the foot damage that results from it.
Now let’s talk about how medical treatments themselves can sometimes cause flat feet in adults.
Surgeries can change how your feet work.
Some foot surgeries accidentally cause flat feet by changing your foot’s natural mechanics. Procedures like triple arthrodesis, calcaneal osteotomies, or big tendon transfers can mess up the careful balance that keeps your arch up.
Even though these surgeries fix one problem, they might create new ones. Your arch can slowly collapse months or even years after surgery. Research shows about 8% of people who had surgery for flat foot on one side ended up with flat foot on their other foot within five years. This happens because their walking pattern changed, putting more stress on the good foot. That’s why it’s so important to check your foot mechanics thoroughly before and after any surgery. This helps spot who might be at risk for developing flat feet from medical treatment.
Steroid shots can weaken your foot tissues too.
Cortisone shots might help with pain short-term, but getting them too often around important foot structures can weaken your tendons and ligaments. This can speed up arch collapse.
Here’s how it works: steroids slow down your body’s ability to make collagen and repair tissues. This makes the structures that hold up your arch weaker.
One foot specialist warns that just one cortisone shot near your posterior tibial tendon comes with about a 10% chance of the tendon tearing later. This risk is especially high for middle-aged people who already have some tendon wear and tear.
Doctors really need to weigh the pros and cons when treating posterior tibial tendonitis. Many now prefer alternatives like PRP injections, which might actually help healing instead of weakening tissues.
So to sum up, adults can develop flat feet for many reasons. These include worn-out tendons, arthritis, injuries, nerve problems, whole-body diseases, and even medical treatments themselves.
What all these causes have in common is they upset the balance between the moving parts (like your posterior tibial tendon) and the non-moving parts (like your spring ligament) that work together to keep your arch up.
Catching the real cause early means you can get the right treatment to stop the problem before your foot becomes permanently flat. Since many adults don’t get diagnosed right away, it helps to know about all these different causes so you can get help sooner.
If this info about what causes flat feet in adults helped you, maybe share it with someone else who could use it. Want to learn more about fixing collapsed arches? Check out our full guide on both non-surgical and surgical treatments.
Frequently Asked Questions About Adult Flatfoot Causes
Can adults suddenly develop flat feet?
Most adult flat feet develop slowly over months or years, but sometimes arches can collapse pretty quickly. A sudden tendon tear after injury, diabetic nerve problems.
or arthritis flare-ups can cause obvious foot changes in just weeks. But usually there were already hidden issues before the big change showed up.
Does being overweight directly cause flat feet?
Being heavy doesn’t directly cause flat feet, but it definitely makes it more likely. Extra weight puts more strain on your foot tendons and ligaments, making them wear out faster if they were already weak.
Studies show overweight people get painful flat feet 5-7 years sooner, so watching your weight really helps prevent it.
What health problems usually cause flat feet in adults?
Common causes are rheumatoid arthritis that damages joints, diabetes that affects nerves, high blood pressure that weakens tendons, and genetic conditions like Marfan syndrome.
Old ankle or foot injuries also often lead to flat feet, especially if they hurt the main ligaments or made joints unstable.
Can bad shoes give you permanent flat feet?
Bad shoes alone usually don’t cause permanent flat feet, but they can speed up the process if you’re already prone to it. Shoes without good arch support make your foot muscles and ligaments work overtime.
which can turn hidden flat feet into painful ones. That’s why good shoes are key for both preventing and managing early flat feet.
