Flatfoot is a common foot deformity that lacks the natural longitudinal arch of the foot skeleton. Read all about it!


Of the flatfoot (pes planus) is a foot deformity that lacks the natural longitudinal arch of the foot skeleton (arch of the foot). One speaks of the flat foot, when standing the entire sole of the foot has contact with the ground. A flatfoot can be innate or arise in the course of life. Depending on its severity, the flat foot can cause pain and restrict movement. Read all about flat feet and how to treat them.

ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in doctor's letters or on incapacity certificates. M21Q66

Product Overview


  • description

  • symptoms

  • Causes and risk factors

  • Examinations and diagnosis

  • treatment

  • Disease course and prognosis

Flatfoot: description

In contrast to a healthy foot, the foot skeleton has no longitudinal arch when flatfooted. So it lacks the natural outward curvature from the heel to the forefoot bale. As a result, the inner edge of the foot drops, so that the entire sole of the foot rests flat on the floor when standing.

In a flat foot but usually disappears not only the longitudinal arch. Depending on the form and expression, there are further deformities of the foot skeleton. For example, the outer edge of the foot is raised (pronation). The Achilles tendon may be shortened and, moreover, the heel and forefoot often buckle to the outside (valgization or abduction). In such cases, doctors therefore also speak of a kink flat foot.

A precursor of the flat foot is the Senkfuß. Even with this shape, the foot skeleton loses its longitudinal arch, however, the sole of the foot is not yet completely on the ground.

Which forms of a flat foot are there?

A flat foot can already exist from birth, or be acquired, so occur later in life. The congenital form differs substantially from the acquired types, especially as regards their frequency, development and treatment.

Congenital flat foot (Pes planus congenitus)

The congenital flatfoot is rare and often occurs together with other malformations or diseases. It can be a foot alone or both affected. In the affected babies shows a very pronounced malposition of the foot. So he not only loses his natural Längswölbung, but is bulged even at the bottom even down.

The reason for this form of flatfoot is that certain tarsal bones have a wrong position. The talus which connects the foot to the leg is too steep and is also displaced towards the inside and sole of the foot. Thus, the talon can not form normal joints with other tarsal bones. The upright position of the ankle also refer to physicians as "talus verticalis".

Acquired flat foot (Pes planus valgus)

Patients with an acquired flatfoot are initially born with a healthy foot skeleton and only later develop the deformity. Depending on the age at which it occurs, different types of acquired flatfoot can be distinguished:

  • Acquired, childish kink flatfoot: It occurs about the beginning of the age.
  • Adolescent flatfoot: develops in adolescence.
  • Adult flatfoot: may also occur later in life.

The acquired, childish kink flat foot must not be confused with the natural (physiological) kinking foot in childhood: Children have a different leg position than adults until the age of six. Because their thighbones are oriented differently, they go slightly x-legged, which also affects the foot position. A transient kinking foot is the result.

The strong longitudinal vault forms only between the sixth and the tenth year of life, even if the leg position normalized. The acquired, childish kink flatfoot, on the other hand, has non-natural causes and remains permanent without treatment.

Flatfoot: symptoms

Whether a flat tire causes problems and if so, how strong they are, depends largely on the cause and nature of the malposition. While the congenital flatfoot without therapy usually causes more and more complaints, mild acquired forms can be completely symptomless.

Symptoms of congenital flatfoot

The congenital flatfoot is noticed immediately after birth. The malpositions on the foot - such as the outward curved sole, the bent heel and the splayed out front foot section - are very pronounced here.

The affected children usually learn to go later than their peers. Without timely treatment, however, the movement is limited, also suffer from the late school age usually increasingly in pain.

Symptoms of acquired flatfoot

The acquired, childish flatfoot is usually symptom-free. The children only stand out due to the visible deformity on their feet. Depending on the cause, the movement may also be impaired.

Flat feet, which occur in adolescence, are usually associated with severe, sudden stress pain. The teens limped to protect the affected foot. Without treatment, an adolescent flatfoot can severely restrict the movement.

Adults who develop a flatfoot often have discomfort there after heavy exercise. Above all, as long as the arch of the foot is still lower, pain will occur, the sole of the foot will be completely raised, and it will often be removed.

In a flat foot, the pain is usually on the inner edge of the foot and on the sole of the foot. The malalignment can also cause pain in the knees and even on the hip. Excessive stress on certain parts of the foot can also develop pressure points, which sometimes cause additional pain and make walking difficult. In many cases, however, those affected have no problems walking.

Flatfoot: causes and risk factors

The congenital flat-foot seems to be primarily hereditary, as it often has several members of a family. However, this does not mean that a child must necessarily be born flat-footed if a parent was affected. Only the probability increases. The exact causes of a congenital flatfoot are not yet known.

There can be many triggers for an acquired flatfoot. The most common ones include:

  • Long-lasting fault and overload. This is often the reason for a flatfoot ("apprentice flatfoot")
  • Connective tissue and muscle weaknesses. The acquired, childish kink flatfoot is often due to muscle weaknesses.
  • Arthritis (rheumatoid arthritis) often occurs at an older age, but can also affect young people.
  • Injuries after accidents or signs of wear (osteoarthritis)
  • Nervous diseases and paralysis
  • the pathological growing together of several foot bones
  • too tight footwear, which does not allow the foot and toe movement

In older people, a pathologically altered tendon in the lower leg (tibialis posterior tendon) may be the cause. If the tendon is heavily loaded for a lifetime, it can regress or break and thus lead to a one-sided flat foot.

Flatfoot: examinations and diagnosis

To diagnose the acquired flatfoot, the doctor checks to what extent the arch of the foot is still present. He examines his feet when the patient is standing on the floor. Depending on how pronounced the flat foot is, the entire sole of the foot lies more or less strongly on the ground.

Another method is the footprint on an electronic measuring plate or a suitable modeling compound. Here, the weight distribution of the sole of the foot can be easily understood.

If the flat foot is not determined externally, you take an x-ray. In congenital flatfoot this is basically for confirmation.

A ruptured tibialis posterior tendon, which is often the cause of a one-sided flatfoot, recognizes the doctor by looking from behind at the feet standing on the ground. While only the heel can be seen on a healthy foot, one can also recognize the toes on the injured foot. ("Too many toes sign").

Flatfoot: treatment

There are several ways to treat flat feet. While acquired forms often require no surgical intervention, surgery for congenital flatfoot is usually unavoidable.

Therapy for congenital flatfoot

First, prepare the children for a future operation. For this they put a plaster on the affected foot, which counteracts the malposition. This measure alone is not enough. Therefore, children are usually operated on until the age of three to correct the wrong position of the tarsal bones. This is followed by a post-treatment with special deposits and plaster casts, which can take months or even years. If there is still a misalignment after completing foot growth, it may be necessary to re-engage.

Therapy for the acquired flatfoot

Exercises in the field of physiotherapy, which strengthen the muscles in the foot and lower leg, are especially helpful in the early stages of an acquired flatfoot. Also special orthopedic shoe inserts can bring the foot back into shape. If the acquired flatfoot causes severe pain, the doctor prescribes medication.

If the symptoms do not improve, surgery may also be necessary for the acquired flatfoot. Especially flat feet, which are caused by arthrosis or a torn tibialis tendon tend to be operated frequently.

Flatfoot: Disease course and prognosis

The congenital flat foot disturbs the walking and mobility of the child. However, timely surgery usually corrects the malposition.

In mild, acquired forms, those affected often have no complaints. However, if problems do occur, the acquired flatfoot can usually be treated well with the aid of a special shoe insert.

The risk of getting a flatfoot is reduced by avoiding excessive and one-sided stress on the feet. In addition, there is a good and just as simple training for the feet: Who regularly goes barefoot, trains the muscles and ligaments on the foot and thus prevents an acquired flatfoot in front.

Read more about the therapies

  • External fixator
  • plaster cast
  • Orthopedic insoles
  • Orthopedic shoes
  • osteosynthesis
  • osteotomy

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