Flat Feet and Orthotics

Pes planus (PP) is the complete loss of the arch of the foot. When this occurs the sole of the foot comes into either complete—or almost complete—contact with the ground. There are several factors that can contribute to the development of flat feet but treatment is generally pursued only if the arches suddenly collapse, if pain or discomfort develops, if a long-term case gradually worsens, or if there is a serious deformity developing or other serious symptoms are caused by this condition.

Because pes planus affects the entire foot and not just the arch there are several conditions that often occur in tandem with fallen arches:

• The heel may turn outward (valgus position)

• The mid-foot may pronate (may turn inward; also referred to as hyperpronation)

• The forefoot may turn outward (valgus position)

It’s important to note that pes planus refers to the bones in the feet and not the soft tissues. People who have hypertrophied plantar foot muscles (which often occurs if a patient has spent most of their life barefoot) appear to have flat feet because their arches are flat but hypertrophy is an issue of soft tissues where the bones remain normal.

This condition may be congenital or it can develop over time, and some cases are flexible while others are fixed.

Primary Causes of Pes Planus

There are several possible causes of this condition in both children and adults. Here is an overview of both categories:


Perhaps surprisingly flat feet are often part of the normal development of children; in fact, most infants do not have a highly developed arch to their foot and a majority of toddlers experience a flat arch, pronation in their forefoot and an outwardly turning heel during weight-bearing activities. And while some children may be genetically disposed to ligamentous laxity most will go on to develop a normal (and strong) arch at approximately 10 years of age.

Pen Planus may also be caused by an abnormal development of the foot due to neurological conditions such as polio or cerebral palsy, or abnormal development of bones or ligaments, (such as tarsal coalition).


Approximately 20% of adults have pes planus, and most of these adults have flexible feet with very few symptoms of their condition unless a heel cord contracture occurs. As with children there are several factors that can cause flat feet in adults. Physiological factors are perhaps the most common and this includes inherently lax ligaments, which can lead to faulty arch development that can lead to flat feet.

Adult-acquired pes planus can be caused by the following conditions:

• Improper functioning of the tibialis posterior tendon; this is a common and significant cause of flat foot.

• A more rare cause is the tear of the spring ligament.

• Also rare is a Tibialis anterior rupture.

• Neuropathology that affects the feet, e.g: diabetes.

• Degeneration of foot and ankle joints from inflammatory diseases, e.g: rheumatoid arthritis.

• Osteoarthritis

• Fractures

• Abnormalities in bone formation, e.g. tarsal coalition

Secondary Causes of Pes Planus

• Footwear: High heels and footwear that lack sufficient space for toe movement.

• Tight calf muscles or a tight Achilles tendon may contribute the development of pes planus. Tight muscles and tendons may also contribute to symptoms such as foot pain in pre-existing cases of pes planus.

• Obesity

• Bone abnormalities pertaining to the tibia, or the fusing of tarsal bones.

• Ligamentous laxity connected to Ehlers-Danlos syndrome or Down’s syndrome.

• Underlying issues that cause foot pronation, e.g. weak hip abductors.


When people decide to see a professional it’s usually because they have a fully developed case of pes planus, because they are concerned about the development of their children’s feet, or because they are in pain. There are a few indicators that most professionals will look for:


• A history of flat foot or changes in the structure and use of the foot.

• They will observe the patient walking/running ability and ask questions about foot pain.

• They will require a medical history including any other diseases or developmental delays that may have been diagnosed or observed.


• You will be asked if the symptoms of flat foot are new

• The presence foot pain or difficulties while walking

• The occurrence of knee or ankle pain

• They will require a medical history including a disclosure of injuries and neurological, rheumatological, musculoskeletal issues that may be occurring in the body as well.

• Lifestyle habits and the patient’s occupation.

If it is a new development of pes planus the patient will be asked about their level of discomfort and whether or not this condition is occurring in both feet. The patient will likely also be checked for tibialis posterior dysfunction, which displays the following symptoms:

• Pain or swelling and along the arch of the foot or around the inner side of the ankle bone.

• Noticeable change in the shape of the foot.

• Diminished balance and agility while walking.

• Aching in the foot when walking longer distances.

Physical Examination

1. The first thing your specialist is likely to do is observe your feet from above and behind while you are standing. Your doctor is checking to see if there is a visible loss of your arch and if the medial side of your foot is unusually close to the floor. When looked at from behind a foot with pes planus will likely have a heel that turns outward.

2. Your doctor will also check to see if you have flexible case of pes planus by asking you stand on tiptoe. If you have flexible PP your feet will display a visible arch and your heel will turn inward.

3. You may also be checked to see if you have tibialis posterior dysfunction if there is anything in your medical history that is indicative of this condition. You will be asked to perform 10-12 unsupported heel raises (rising up on tiptoe and down again without support) as people suffering from tibialis posterior dysfunction cannot perform this exercise.

4. Your doctor will also take into consideration of any existing conditions that may be related to your symptoms, such as neurological issues or arthritis.

5. In some cases a standing foot X-ray will be performed to observe the deformities of the foot in more detail. Your doctor will be looking at your longitudinal arch and talonavicular joint and looking for the degree of inward turn to your heal from the talocalcaneal angle.


Most cases of pes planus do not require treatment, and there is good reason for that:

• Children younger than 10 years old who have flexible PP with no other relevant conditions often develop strong and healthy arches naturally.

• Adults who have had flexible, PP for many years, who do not experience impairment when walking, who do not suffer from foot pain, and who are not experiencing a progression in their symptoms are not required to undergo treatment as it is unnecessary.

Treatment for pes planus is considered under the following conditions:

• The condition is fixed (lacking flexibility)

• If the condition is asymmetrical or progressing

• If the patient is experiencing foot pain

• If the patient suffers from neuropathy or inflammatory arthritis.

• When tibialis posterior dysfunction is present. If it is then it will need to be treated on its own with rest, non-steroidal anti-inflammatory drugs, orthotic devices, or if all else fails, surgery.

Non-Surgical Treatments for Pes Planus

There are several effective non-surgical treatments available for flexible PP if the situation demands:

• Heel stretches are crucial for treatment, because a tight Achilles tendon will usually cause the foot to pronate, placing excessive strain on the structure of the feet.

• Orthotics inserts—especially if they are customized—usually give great results. The most common kind of insert used is a heel wedge, which provides arch support and helps to correct calcaneovalgus deformations. A well- structured insole may help prevent the progression of pes planus and may also help to reduce the occurrence of uncomfortable symptoms; however, care must be taken as using insoles without addressing heel cord tightness can make symptoms worse.

A slightly different approach may be taken with patients suffering from fixed PP although the use of custom insoles is often used in these cases as well:

• Modifying footwear; aside from the introduction of custom orthotics shoes with wide toes and low heels should be worn on a regular basis.

• Maintain a healthy weight/lose weight if necessary.

• Strengthen the muscles of the foot through walking barefoot on grassy or other forgiving surfaces (taking care not to cut or injure the feet), and by performing toe curls and supported or unsupported heel raises.

Heel cord exercises are a crucial part of both treatments and these stretches should be performed regularly in order to loosen and lengthen both the muscles in the calf and the Achilles tendon:

1. Face a wall with your hands planted at eye level. Place your left leg behind you. This is the leg you are going to stretch first.

2. Keep your back leg on floor as you bend your front knee until you feel the stretch in your left (back) leg.

3. Hold the stretch for 20-30 seconds, relax, and repeat 2-4 times.

4. Switch legs and repeat the entire process with the right leg.

5. Perform this stretch on both legs 3-4 times per day.

Surgical Treatment for Pes Planus

Particular cases of pes planus may benefit from surgical treatment:

• If the patient suffers from cerebral palsy causing an equinovalgus foot then surgery might help prevent deterioration of the midfoot

• Painful PP and rigidity of one or both feet

• Surgery may be used to prevent gradual progression of symptoms with conditions such as Charcot joint

• Surgery is an option when treating Tibialis posterior dysfunction only when non-surgical treatments have failed.

There are a few different procedures that can be performed, such as:

• Lengthening of the Achilles tendon.

• Re-aligning the hind-foot through Calcaneal osteotomy.

• Tibialis posterior tendon reconstructive surgery.

• Triple arthrodesis, though this type of surgery is used only in severe cases of mid-foot arch collapse.


It is generally accepted that pes planus does not usually cause serious foot problems, although there are well noted exceptions to this generalization. Excessive foot pronation however, which is usually symptomatic of PP, often causes foot pain to develop and the following foot problems to occur:

• Improper functioning of the posterior tibialis posterior dysfunction, as hyper- pronation will lead to a gradual overstretching of this tendon.

• Bunions, which are caused excess weight on the medial metatarsals when the feet hyper-pronate.

• Metatarsalgia, for the same reasons that bunions develop.

• Plantar fasciitis.

• Knee pain: Studies have indicated that knee pain can be caused by problems with the foot, which often meant that orthoses reduced patellofemoral discomfort but it’s also possible that foot deformities may be linked to the presence of knee osteoarthritis.

• Having pes planus may make the foot less able to properly absorb the impact of the foot hitting the ground which may contribute to lower back pain.

While it has yet to be confirmed that pes planus plays a significant role in the development of these conditions it is quite likely that it is a contributing factor, in which case various treatments may be undertaken to correct the problem, though treatment is by no means always necessary.