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Anurag
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Anurag
Published Date24 Sept'26
Last Updated24 Sept'26
Read Time16 Minutes
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Yes, flat feet may contribute to knee pain in some people, but having flat feet does not automatically mean you will develop knee pain.
Flat feet can influence how the foot interacts with the ground during standing, walking and running. Because the foot is part of a connected lower-limb movement system, changes in foot posture and mechanics may be associated with changes in movement and loading at the ankle, leg and knee.
However, knee pain has many possible causes. Flat feet should therefore be considered as one potential contributing factor, rather than assuming they are always the cause.
Research has found associations between flatter foot morphology and knee pain, particularly in some older adults and people with knee osteoarthritis. For example, a large study of 1,903 older adults found that people with the most planus (flat) foot morphology had higher odds of frequent knee pain and medial tibiofemoral cartilage damage.
Flat feet can be associated with knee pain, but they do not necessarily cause it.
A lower or flattened arch can be accompanied by changes in foot posture and gait mechanics. These changes may influence how forces are transmitted through the lower limb.
The potential relationship can be simplified as:
Foot structure → foot mechanics → lower-limb movement → knee loading → symptoms in some people
But this is not a guaranteed cause-and-effect chain.
A person can have flat feet without knee pain, while someone with normal-looking arches can experience knee pain for completely different reasons.
Flat feet may contribute to knee pain in some individuals, but flat feet alone do not prove that they are responsible for knee pain.
Flat feet, also called pes planus, describe a foot with a relatively low or flattened medial longitudinal arch, particularly when the foot is bearing weight.
The appearance of the arch can vary considerably between people.
Some people naturally have:
Low arches
Flexible flat feet
Flat feet in both feet
Flat feet in only one foot
Flat feet without pain or functional limitations
A low arch is therefore not automatically a medical problem.
If you want to understand the different types of foot arches, see:
What Are the Different Types of Foot Arches?
You can also compare normal, low and high arches here:
Normal Arch vs Low Arch vs High Arch: What's the Difference?
The foot is the foundation of the lower limb.
When you stand or move, your foot interacts with the ground and helps transmit forces upward through the ankle and leg.
Changes in foot posture can therefore be accompanied by changes in lower-limb movement.
This does not mean that every person with flat feet has abnormal knee mechanics.
Instead, researchers study whether particular foot structures or movement patterns are associated with measurable differences at the knee.
A 2026 systematic review found that people with flatfoot demonstrate some differences in gait characteristics compared with healthy controls, including longer stance duration and shorter stride length, although substantial variation existed between studies.
A simplified model looks like this:
Flat or low arch
↓
Possible changes in foot position and motion
↓
Changes in ankle and lower-leg mechanics
↓
Potential changes in knee movement or loading
↓
Knee symptoms in some individuals
This is a useful way to understand the possible connection, but it should not be interpreted as proof that flat feet directly cause knee pain in every person.
No.
Many people have flat feet and never develop knee pain.
Foot shape varies naturally between individuals, and the presence of a low arch alone does not tell you whether a person will develop symptoms.
Other factors can influence knee pain, including:
Age
Previous injury
Activity level
Training load
Muscle strength
Joint alignment
Body weight
Osteoarthritis
Movement patterns
Previous surgery
Other musculoskeletal conditions
Therefore, flat feet should not be treated as a diagnosis for knee pain by themselves.
Research has identified associations between flat feet and knee symptoms in certain populations.
Flat feet and knee pain in older adults
A large study involving 1,903 older adults investigated the relationship between planus foot morphology, knee pain and cartilage damage.
The researchers found that participants with the most planus feet had approximately 1.3 times the odds of knee pain and approximately 1.4 times the odds of medial tibiofemoral cartilage damage compared with participants with other foot types.
The study was observational, meaning it demonstrated an association rather than proving that flat feet caused the knee problems.
Flat feet in people with knee osteoarthritis
Another cross-sectional study involving 95 people with knee osteoarthritis found that bilateral flat feet were associated with greater knee pain.
Participants with bilateral flat feet had significantly higher reported knee pain than those without flat feet, and the researchers found an association after adjusting for several factors. However, the authors specifically noted that prospective research would be needed to establish a causal relationship.
Flat feet and knee osteoarthritis severity
A separate study of 95 patients with knee osteoarthritis reported that the presence and severity of flat feet were associated with greater knee osteoarthritis symptoms, including pain and functional limitations.
These findings make the foot–knee relationship worth investigating, but they should not be interpreted as:
“Flat feet cause knee osteoarthritis.”
The more accurate interpretation is:
Flat-foot morphology has been associated with knee pain and some knee-related structural findings in certain populations.
They may contribute to knee discomfort during walking in some people, but not everyone with flat feet will experience this.
Walking requires coordinated movement across the foot, ankle, leg and knee.
If foot posture or mechanics alter how forces are transmitted through the lower limb, this may affect movement at other joints.
Recent research has examined gait in people with flat feet and found differences in several spatiotemporal characteristics compared with healthy controls. However, the available evidence is heterogeneous, meaning not every study identifies exactly the same gait changes.
If your knee hurts specifically while walking, it is therefore useful to consider:
How long you walk
Whether the pain occurs immediately or after prolonged walking
Whether one or both knees hurt
Whether you also have foot or ankle symptoms
Whether your walking pattern has changed
Whether the pain began after an increase in activity
Flat feet may be associated with differences in running mechanics, but they do not automatically cause running-related knee pain.
Running increases repetitive loading compared with ordinary walking, so individual biomechanics may become more noticeable during higher-impact activities.
However, knee pain in runners can result from many factors, including:
Sudden increases in training volume
Changes in running surface
Muscle weakness
Previous injury
Poor recovery
Training technique
Foot and ankle mechanics
Hip and knee mechanics
A 2025 systematic review and meta-analysis examined foot orthoses and lower-extremity mechanics in runners with asymptomatic flat feet. The evidence showed that different orthotic designs could produce different biomechanical effects, reinforcing the point that flat-foot structure and running mechanics are not interchangeable concepts.
Flat feet may be associated with changes in lower-limb alignment and movement, but the relationship is individual and more complicated than simply saying “flat feet knock the knees inward.”
The foot, ankle, tibia, knee and hip work together during movement.
A change at one joint can alter movement elsewhere, but the magnitude and direction of that effect can vary.
Research into knee osteoarthritis has also examined the relationship between malalignment, joint loading and disease progression. A systematic review found strong evidence that knee malalignment is associated with progression of radiographic knee osteoarthritis, although that is different from proving that flat feet themselves cause knee malalignment.
Therefore, avoid assuming that a particular knee alignment problem is caused by flat feet without an appropriate assessment.
Possibly, but inner knee pain has many potential causes.
The medial or inner side of the knee can become painful for several reasons, including:
Osteoarthritis
Meniscus problems
Ligament injuries
Tendon or muscle problems
Overuse
Training-related injuries
Changes in lower-limb mechanics
Flat feet may be one factor influencing overall lower-limb mechanics, but they cannot be assumed to be the cause based solely on where the pain occurs.
Front-of-the-knee pain can have several causes, including patellofemoral pain.
Foot and ankle mechanics have been investigated in people with patellofemoral pain. A 2026 systematic review and meta-analysis found evidence of greater navicular drop in people with patellofemoral pain, while evidence for several other foot and ankle measures was limited. The authors also cautioned that the predominantly case-control evidence does not establish causation.
Therefore, it would be inaccurate to say:
“Flat feet cause patellofemoral pain.”
A more evidence-based statement is:
Certain foot and ankle characteristics have been associated with patellofemoral pain, but the relationship is multifactorial and does not establish that flat feet alone cause the condition.
Knee pain on stairs can occur with conditions such as:
Patellofemoral pain
Knee osteoarthritis
Tendon problems
Previous injury
Muscle weakness
Flat feet may influence lower-limb mechanics, but they are not necessarily the underlying cause.
If you consistently experience knee pain when climbing or descending stairs, especially if it is worsening or limiting your daily activities, consider professional assessment rather than assuming the problem is simply your foot arch.
The foot is part of a larger kinetic chain.
During movement, the following structures work together:
Foot → ankle → lower leg → knee → thigh → hip
Changes in foot posture can be accompanied by changes elsewhere in the chain.
For example, research into flexible flat feet has examined:
Rearfoot movement
Ankle motion
Tibial movement
Knee mechanics
Lower-limb joint moments
Walking patterns
A 2024 systematic review and meta-analysis found that foot orthoses could alter selected lower-limb joint angles and moments during walking in adults with flexible flat feet.
Importantly, this does not mean that every person with flat feet has abnormal lower-body mechanics.
Flat feet, overpronation and knee pain are often discussed as though they are three stages of the same problem.
They are not.
Flat feet
Primarily describe foot structure, particularly a lower medial arch.
Overpronation
Describes a movement pattern involving pronation during gait.
Knee pain
Describes a symptom, not a specific diagnosis.
They can occur together, but one does not automatically prove the presence or cause of another.
For a detailed explanation of the relationship between flat feet and overpronation, see:
Flat Feet and Overpronation: What's the Connection?
That article should be your primary resource for the flat feet → overpronation topic, while this article focuses specifically on the flat feet → potential knee symptoms relationship.
You generally cannot determine this from arch height alone.
Instead, consider the broader picture.
1. Do you have flat feet?
You can assess your arch using several simple methods, although home tests are not diagnostic.
Read:
How to Tell What Type of Foot Arch You Have
You can also learn about the wet foot test:
Wet Foot Test: How to Check Your Arch Type at Home
2. Do you have knee pain?
Consider:
Where the pain occurs
When it occurs
Whether it affects one or both knees
How long it has been present
Whether activity makes it worse
3. Do you have foot or ankle symptoms?
If knee pain occurs together with foot fatigue, ankle discomfort or other lower-limb symptoms, the entire movement chain may be worth assessing.
4. Did the pain start after an activity change?
A sudden increase in:
Walking
Running
Gym workouts
Sports
Standing time
can contribute to knee pain independently of foot structure.
5. Has your foot structure changed?
A newly developed or progressively worsening flat foot deserves more attention than a low arch that has been present for years without symptoms.
They can be associated with pain in both knees, but bilateral knee pain does not prove that flat feet are the cause.
Interestingly, the 2017 cross-sectional study of people with knee osteoarthritis found an association between bilateral flat feet and increased knee pain, while unilateral flat feet were not significantly associated with the measured outcomes. The researchers emphasized the need for prospective studies to determine whether the relationship is causal.
This is an example of why laterality and individual assessment matter.
Not necessarily.
This is an important distinction from Article 24.
Flat feet and overpronation can be related, but neither one automatically means that knee pain will develop.
A simplified model might be:
Low arch → altered foot mechanics → possible changes in lower-limb movement → possible changes in knee loading
But there are many variables between these stages.
For a deeper explanation of overpronation itself:
Flat Feet and Overpronation: What's the Connection?
Arch support may influence foot and lower-limb mechanics, but it should not automatically be considered a treatment for knee pain.
Research has shown that foot orthoses can alter selected lower-limb joint angles and moments in adults with flexible flat feet.
However, changing foot mechanics does not necessarily mean that knee pain will improve in every person.
The design of the support also matters.
Research in runners with asymptomatic flat feet found that orthoses incorporating medial posts produced some measurable biomechanical changes, whereas arch-support-only designs did not show the same effects across the analyzed outcomes.
If you want to understand arch support specifically, read:
Do Flat Feet Need Arch Support?
and:
How Does Arch Support Help Flat Feet?
Insoles or foot orthoses can alter aspects of foot and lower-limb mechanics, but whether they reduce knee pain depends on the individual and the underlying cause.
It is therefore better to think of an insole as one possible component of management, rather than assuming it will fix knee pain caused by flat feet.
Research into flexible flat feet has found that orthoses can modify selected lower-limb mechanics during walking.
If you're researching insoles specifically, these guides are more relevant:
How to Choose Insoles for Flat Feet
Exercise may be part of managing symptoms associated with flat feet or knee pain, depending on the individual's underlying problem.
Potential areas that a qualified professional may consider include:
Foot and ankle strength
Calf strength and flexibility
Lower-leg control
Quadriceps strength
Hip strength
Balance
Movement control
However, the appropriate exercise program depends on the cause of the knee pain.
If knee pain is persistent, exercise selection should ideally be based on an assessment rather than choosing exercises solely because you have flat feet.
Not necessarily.
If you have asymptomatic flat feet, there is no reason to assume that your feet must be "corrected" simply because your arches are low.
The more useful question is:
Are your foot mechanics contributing to symptoms or functional limitations?
This distinction is important because flat feet can be a normal anatomical variation.
For a deeper explanation of what arch support can and cannot change, see:
Can Arch Support Correct Flat Feet? What It Can and Can't Do
Consider seeking professional assessment if you have:
Persistent knee pain
Knee pain that is getting worse
A newly developed flat foot
A rapidly changing arch
Significant difference between your two feet
Swelling around the knee or foot
Difficulty walking
Difficulty climbing stairs
Repeated knee injuries
Significant pain during exercise
Weakness or instability
Numbness or tingling
A physiotherapist, podiatrist, sports medicine professional or other qualified healthcare provider can assess the foot, ankle, knee and movement pattern together.
This can be more informative than assessing arch height alone.
Don't automatically assume that the flat feet are responsible.
Instead, consider the complete picture:
Where does your knee hurt?
When does it hurt?
Did the pain develop gradually or suddenly?
Does activity make it worse?
Do you have foot or ankle symptoms too?
Has your activity level recently changed?
Have you previously injured the knee?
These questions can help distinguish a possible biomechanical contribution from other causes of knee pain.
The current evidence supports a relationship worth considering, rather than a simple cause-and-effect rule.
Studies have reported:
Associations between flatter foot morphology and knee pain in older adults.
Associations between bilateral flat feet and greater knee pain in people with knee osteoarthritis.
Associations between flat-foot severity and knee osteoarthritis symptoms in some patient groups.
Differences in gait characteristics among people with flat feet compared with healthy controls.
Measurable effects of foot orthoses on selected lower-limb mechanics in adults with flexible flat feet.
But these findings do not mean:
Flat feet always cause knee pain.
or:
Everyone with flat feet needs orthotics.
The relationship between foot structure, movement, loading and symptoms is individual and multifactorial.
If you remember only a few things from this article, remember these:
Flat feet can be associated with knee pain, but they do not automatically cause it.
Flat feet primarily describe foot structure, while knee pain is a symptom.
Foot posture can influence lower-limb mechanics, but the effect varies between individuals.
You can have flat feet without knee pain.
Knee pain can occur without flat feet.
Overpronation may be associated with flat feet, but it is a separate concept.
Research has found associations between flatter foot morphology and knee pain in certain populations.
Foot orthoses can influence some aspects of lower-limb mechanics, but this does not mean they will eliminate knee pain in everyone.
A newly developed or worsening flat foot combined with pain deserves professional assessment.
The goal should be to understand the individual cause of the knee pain, rather than automatically blaming the foot arch.
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