Flat Feet (Pes Planus)

Having flat feet describes the biomechanical and structural positioning of one or both feet, which is characterised by rolling in at the ankles and showing little to no arch on the inside border of a foot. This is how the term ‘fallen arches’ was coined. This is medically referred to as pes planus, with the term for rolling in at the ankle joint when walking known as pronation. As the severity of pronation can range from mild to severe, podiatrists can measure the angle of your shin bone relative to your calcaneus, or use a Foot Posture Index (FPI), to help grade the level of pronation and best direct treatment where it is indicated.   It should be noted that:
  • Flat feet are relatively common, and having flat feet does not mean you are definitely going to have foot or leg issues or pains
  • Pronation is also a natural and necessary part of each step we take, helping our feet to absorb shock and adapt to the uneven surfaces
Flat feet are, however, linked with a greater incidence of foot problems because of the effect this position has on your bones, joints, muscles and ligaments. This happens because we over-pronate past the point that is necessary and healthy for our feet.  

What causes flat feet and overpronation?

Typically, it comes down to the biomechanics of your feet and the way your bones, joints, muscles and ligaments are working together. Some people may have flat feet from birth and others may develop them over time and in association with other conditions. Causes may include:
  • Bone or joint irregularity
  • Muscle weakness
  • Tendonitis, such as in the posterior tibial tendon
  • Ligament laxity
  • Obesity
  • Pregnancy
  • Injury / Trauma
  • Arthritis
  • Diabetes
  • Other medical conditions
In childhoodkids are born with the appearance of having flat feet when they are standing because their feet have fat pads. Most children outgrow it eventually as their feet get larger, their baby fat disappears and their foot muscles strengthen with weight bearing activity such as walking. If your child does not develop arches by the time they are 8 years old, it is not likely they will have an arch in adulthood.  

What are the symptoms of flat feet?

The symptoms of flat feet aren’t necessarily painful themselves, but the stress and pressure they put on the surrounding tendons and structures can cause pain as tendinopathies and other issues develop. These tend to be exacerbated by long periods of time on the feet and high-impact activities. When podiatrists evaluate the severity of flat feet, they often look for signs as opposed to symptoms. These include:
  • Shoes wearing out quickly on the inner side
  • Talonavicular bulging (a bulge on the inside of the foot)
  • Abducted forefoot (seeing your toes pushing out on the outside of the feet when looking at the heel)
  • The position of your heel bone and whether it’s rolling in or out
  • The shape of your arch
  • Talar head palpation (being able to feel the head of your talus bone at the ankle evenly when you’re standing)
  • The curvature below your malleoli (bony bumps on the sides of your ankle)
  • The position of your feet in a ‘neutral’ position (referred to as ‘subtalar joint neutral’) versus their position when standing relaxed

How are flat feet treated?

Typically, treating flat feet is more to do with treating the problem the flat feet are creating or contributing to as opposed to treating flat-footedness itself. Where no symptoms or issues occur with flat feet, treatment may not be indicated. Generally, orthotics are a common way to alter the alignment and positioning of the feet and are used in the management of various conditions where overpronation is causing problems and pain. Having supportive footwear that stabilise the foot and ankle as opposed to letting it roll is also a key part of management. If you’re worried about the effect that your flat feet are having on the rest of your body, you should get assessed by your podiatrist. They’ll be able to show you the impact on your feet and legs and discuss with you the appropriate management options in light of your symptoms.