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Oxford University Hospitals NHS Foundation Trust
Foot and Ankle

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Flat feet (Plano-valgus Foot)

This is a condition where the foot doesn't have a normal arch. It may affect one foot or both feet. Most people have a gap between the inner side of the foot and the ground when they are standing. This is referred to as an 'arch'. People with feet that have a low arch or no arch at all are referred to as having flat feet or fallen arches.

Flat feet is a biomechanical problem condition. This condition is experienced by a surprisingly high percentage of the population. It can cause the foot to roll inwards in order to gain contact with the floor and support the weight of the body, and is the main clinical feature of excessive pronation.

This may result in:

  • the heel moving outwards
  • the achilles tendon becoming tight as a result of the position of the heel
  • the forefront of the foot may need to rotate inwards to balance the heel position
  • the foot may begin to slant outwards from the middle of the foot.

The majority of people with flat feet can be helped with orthotics (foot arches, insoles etc.). However, surgery may be required for people with flat feet due to tibialis posterior dysfunction which orthotics have failed to resolve and the rigid (and painful) adult flat foot condition. Surgical options should be discussed fully with your surgeon.