Flat-foot - Pes Valgus

Flat-footedness is a number of different conditions all caused by the absence of the arch in the foot. The front of the foot is turned outwards. The outer edge is further out than the lateral malleol.

There is a distinction between a mobile and a rigid flat. In the mobile state the foot arch will appear when the patient is standing on his toes. In the rigid state the arch does not even appear when there is no strain on the foot.

The causes of flat-foot can be

A. Idiopathic (unknown)
B. Too short an Achilles tendon
C. Muscular tibialis posterior
D. Polio
E. Rheumatoid arthritis
F. Injury
G. Coaliton
H. Fibrous rigidity.

The idiopathic condition, as the name indicates, is of unknown cause. It is often a milder case of flat-foot that will not give trouble later in life. 

The foreshortened Achilles tendon is the most serious. In a few years it can turn a mobile foot into a rigid one with subsequent problems in running and walking. In the first years of a child's life there is degradation of the medial ligaments of the foot from the navicular bone to the metatarsus. Extension of the ligaments is permanent. The foot cannot be re-stationed later. It will continue to fall back into the valgus position. It is therefore important for the condition to be discovered as soon as possible in order for appropriate treatment to be begun.

This condition is observed when the foot cannot be placed at a right angle with the leg stretched and the foot slightly in adduction ad supination.

If this condition is discovered before any irreversible damage is done, positive results can be obtained by both conservative and operative methods.

Conservative: Treatment should consist of raising the heel so that the foot is not forced into the valgus position. Often it is a matter of a rise of 2-3 centimetres. When the foot is kept in this position, it is unnecessary to adjust the foot arch later on. Correct design can make it almost invisible to others. This cosmetic consideration is especially important to the young.

Operative: Treatment by this means consists of elongation of the Achilles tendon. Similarly a 2-3 centimetre elongation is to be aimed for. As with conservative treatment adjustment of the arch is unnecessary later on. It is often difficult to get a satisfactory balance between footwear and arch support. This calls for intensive work by al the therapists involved.

Inadequate functioning of the musculus tibialis posterior is the most common form of flat-footedness. In some it is congenital. Others acquire it at other stages in life.

It shows itself as the foot sinks in the standing position and patients begin to walk "Chaplin"-like. Asked to stand on their toes it is only with difficulty that they can manage to show an arch.

Those who later in life rupture an arch cannot show an arch at all.


L. Schoite modification. R. Standard support.


L. Schoite modification. R. Standard support.

L. Standard support. R. Schoite modification.

L. Standard support. R. Schoite modification.

Treatment is a Schoite modified arch support. 

Standard arch supports are unable to support the foot adequately. If the feet are adjusted sufficiently, normal athletic running is possible at normal speeds.

In the case of polio none of the muscles maintaining the foot arch work causing it to fall down. Foot orthosis can be performed, the normal position of the bones in the foot maintained preventing wrong positions and possible associated pain.

Rheumatoid arthritis causes the ligaments in the foot to become too weak and the resultant slipping apart of the bones. At the same time pain, when moving the foot, causes immobility of the articuli in the foot which therefore weaken. Treatment consists of individually designed supports to relieve the pressure on the foot. This can be performed by a podiatrist.

Injuries, either to the ligaments and muscles in the foot or to the nerves leading to the foot, can cause flat-footedness. In such cases treatment should be directed at the incorrect foot positions by individually designed supports and by orthosis.

Coalition of the bones in the foot can be treated by removing the coalition operatively.

Fibrous rigidity flat-foot is a combination of different conditions characterised by the foot no longer being able to produce an arch when standing on tiptoes.

It causes different conditions, one of which is osteorthosis in the tarso-metatarsal joints. This is difficult to treat. Early treatment should be considered whilst the foot is still redressible.

Pain is found commonly in the lateral malleol (impingement), or in the medial malleol (distraction of ligament). Both conditions can often be helped with a shock-absorbing arch support.