Flat Feet and Insoles


Pes planus is a condition in which the arch of the foot is completely collapsed, causing the instep of the foot to touch the ground completely, or almost completely. Flat feet are fairly common and there are several factores that can cause this condition to occur, but unless pain symptoms or deformation of the foot are severe treatment for pes planus is not pursued.

This condition affects more than just the arch of the foot however, and secondary issues often occur in people suffering from flat feet:

• The heel of the foot often turns out during weight bearing activities (valgus position)

• Mid-foot pronatation may occur (feet may tilt to the inside; also called hyperpronation)

• The front of the foot often turns outward (valgus position)

Note: Pes planus is a condition that affects the bones in the feet rather than the soft tissues. Plantar foot muscles that have become hypertrophied are similar in appearance to pes planus because the instep looks as though it has collapsed, but hypertrophying is the result of problems with the soft tissue while bone development is completely normal.

Pes Planus can be either congenital or acquired and the two main categories of classification are flexible (the feet maintain their flexibility) and fixed (little or no flexibility in the feet).

Primary Causes of Pes Planus

Pes Planus can occur in both children and adults for various reasons:


Pes Planus is not alarming in children as it is considered to be a normal part of development as most infants and toddlers have peculiar foot characteristics during the first few years of life:

• A well developed arch in young children is very rare
• Excessive pronation of the forefoot frequently occurs
• An outwardly turning heel during weight-bearing activities is often observed in young children

A minimal amount of children are genetically disposed to overly lax muscularity, however, most children who display these symptoms will have developed normal arches—and normal arch strength—by the time they are 10 years old. And if a child is experiencing a flexible case of pes planus their chances of normal development are very high so long as the feet do not become rigid as this can interfere with the development of their bone structure.

It should be noted that pes planus may be the result of irregular foot development that has occurred as a result of a neurological pathology such as cerebral palsy, or Down’s syndrome. It may also occur if there is irregular development in the bones or ligaments, as is the case with tarsal coalition.


Pes planus is fairly common in adults as well; roughly 20% of adult live with ‘flexible’ flat foot syndrome, and unless the heel cord tightens significantly most people do not experience foot or leg pain. Most adults with pes planus are naturally inclined to having lax ligaments, which affects the development of the arch and increases the odds of developing this condition.

When pes planus develops in adulthood it is often due to pre-existing conditions such as:

• Sub-par or inadequate functioning of the tibialis posterior tendon (common)
• A rupture or tear in the spring ligament in the ankle (rare)
• Tibialis anterior rupture (rare)
• Neuropathology issues, such as diabetes that affect the feet (common)
• Inflammatory diseases such as rheumatoid arthritis (common)
• Osteoarthritis
• Fractures
• Tarsal coalition

Secondary Causes of Pes Planus

• Wearing high heels (or any footwear that does not allow sufficient movement of the toes)
• Tight calf muscles
• Tight Achilles tendon
• Obesity
• Abnormal tibial bone development
• Lax ligaments due to Ehlers-Danlos syndrome or Down’s syndrome.
• Pronation of the feet

Seeking Treatment

Most people seek treatment only if they are experiencing discomfort from a severe case of flat feet or if they have concerns about normal development in their children’s feet. Parent understandably can be concerned by ‘normal’ stages of seemingly ‘abnormal’ development.
Most professionals will evaluate a patient along the following lines:


• They will ask about any history of pes planus and about any structural or functional changes in the foot.
• The patient will walk or run while the specialist analyzes the movement
• Any and all foot pain should be reported.
• A full medical history detailing any diseases or developmental delays should be prepared in advance.


• The timeline of development will be queried, e.g. when did pes planus develop?
• Are you experiencing foot pain or experiencing difficulties with mobility?
• Is there pain in the knee or ankle?
• A full medical history detailing any injuries or neurological, rheumatological, musculoskeletal issues will be required.
• Your specialist will also ask you questions about your lifestyle and occupation.
• Is it one foot or both feet that are being affected?

Adults will also likely be examined tibialis posterior dysfunction. The symptoms of this condition are as follows:

• Pain or swelling in the arches of the feet or the inside of the ankle bone.
• Visible changes in foot structure.
• Poor balance and reduced agility while mobile.
• Excessively aching feet when walking mid to long distance.

The Examination

1. Your doctor will usually want to look at your feet from above and behind while you take a standing position; this examination will reveal any visible collapse or loss of the arch of the foot. Observing you from behind allows the specialist to check for an outward turn of the heel.

2. You will be examined to determine if your pes planus is flexible or fixed; if there is an observable arch to the foot and your heel is turns inward while you stand on tiptoe then it a case of flexible PP can be confirmed.

3. If anything in your medical suggest you could have tibialis posterior dysfunction your doctor will ask you to do 10-12 unsupported heel raises; if you cannot perform this action further tested will likely be pursued.
4. Your doctor will question you about pre-existing or underlying conditions such as neurological difficulties or arthritis.

5. A standing foot X-rays will occasionally be ordered in order to better observe deformities of the foot, particularly in the longitudinal arch and talonavicular joint.

Pes planus do not always need to be treated for several reasons:
• Children with flat feet and no other symptoms or deformations usually develop strong, healthy arches by the age of 10 without medical intervention.

• Most adults have flexible pes planus and do not suffer from pain, discomfort, or impaired mobility, so unless there is a progression in their symptoms or pain develops there is no need to undergo treatment.
Adults may undergo treatment for PP due to the following developments:
• They are suffering from ‘fixed’ flat foot
• Their symptoms are getting progressively worse
• Foot pain develops
• The patient is suffering from neuropathy or inflammatory disease
• Tibialis posterior dysfunction is found and needs to be treated with rest, anti-inflammatory medication, the use of orthoses, or as a last result; surgery.

Non-Surgical Treatments for Pes Planus

If treatment is needed to reduce discomfort causes by flexible PP there are several options:

• Heel stretches are a compulsory treatment because a tight Achilles tendon causes overpronation in the foot which then excessively strains the soft tissues in the feet.
• The introduction of ortheses often provides relief and prevents further deterioration of the patient’s condition. The effective use of orthotics is more profound when the inserts are custom made. A heel wedge is most productive as it cushions the foot and supports the arch. An orthotic insole may reduce pain symptoms and stem further progression of this condition as well. Heel cord tightness must be addressed if orthotic devices are going to be used; if it is not addressed it can lead to more problems.

Fixed cases of pes planus may require different treatments but the use of custom orthotics is quite common here as well:

• Patients suffering from fixed PP must wear shoes with a low heel and a wide toe box.
• A healthy weight must be acquired and maintained.
• Foot muscles should be strengthened through various recommended exercise, such as unsupported heel raises.

Heel cord stretches are a required component of treating pes planus, especially if orthotic devices are being used. The following stretches should be performed daily so that the Achilles tendon and muscles in the calf become longer and looser:

1. Place your hands on a wall at eye level. Extend your left leg out behind you; you will be stretching this leg first.
2. Push your left leg into the floor and bend your right knee until you feel your back leg being stretched.
3. Hold for 20-30 seconds. Relax for 2 seconds. Repeat 2-4 times.
4. Repeat with the right leg.
5. Perform this series of stretches 3-4 times daily.

Surgical Treatment for Pes Planus

Surgical treatment is usually reserved for the following cases:
• An equinovalgus foot has been caused by cerebral palsy and deterioration of the mid-foot has not yet occurred.
• The patient is experience severe pain and rigidity in their feet.
• Preventing a gradual deterioration of symptoms involving afflictions such as Charcot joint.
• When non-surgical intervention has failed to properly treat difficult cases of Tibialis posterior dysfunction.
There are various surgical procedures that may be performed:
• The Achilles tendon may be lengthened.
• A Calcaneal osteotomy may be used to re-align the hind foot.
• Reconstructive surgery may be performed on the Tibialis posterior tendon.
• If the collapse of the mid-foot if severe enough then triple arthrodesis surgery may be performed.


Most specialists agree that pes planus is not usually a painful or debilitating condition although there are cases to the contrary. Pes Planus usually only becomes an issue because it causes over-pronation of the feet, and this is the condition that in turn causes the following problems:
• Posterior tibialis posterior dysfunction; this tendon becomes overstretched from chronic overprontation of the feet.
• Bunions
• Metatarsalgia
• Plantar fasciitis.
• Knee pain: This type of discomfort is often caused by problems with the foot although it may also be caused by osteoarthritis of the knee.
• Heel and lower back pain: Having flat feet means having less shock absorption when the feet hit the ground.

While it has never been officially proven that pes planus contributes to the development of the previously discussed afflictions it is likely the case. Treatments for pes planus may be undertaken if the need arises but it is no way mandatory unless there are more pressing consequences that develop as a result of this condition.

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