What are flat feet?
Flat feet in adults (also sometimes referred to as Adult-acquired Flat Feet or Posterior Tibial Tendon Dysfunction) is a condition where the arch of the foot collapses, causing all (or most) of the sole of the foot to be in contact with the ground. Flat feet tend to over-pronate (roll inwards), which places strain on ligaments and tendons in the ankle.
The abnormal biomechanics of flat feet can cause symptoms such as low back, hip, knee, ankle and/or arch pain, and can lead to the development of foot arthritis. However, flat feet will not necessarily cause symptoms.
What causes flat feet?
Flat feet in adults can be congenital (when someone is born with a flat foot type), or acquired (a condition that develops over time).
Acquired flat foot is more likely to cause pain and other symptoms. Some of the causes of acquired flat foot include:
- Posterior Tibial Tendon Dysfunction: This condition is one of the most common causes of flat foot, and refers to inflammation and/or overstretching of the posterior tibial tendon in the foot.
- A tight Achilles tendon: If the foot is compensating for a tight Achilles tendon this can cause the foot to flatten
- Compensating for other abnormalities further up the leg
- Rupture of ligaments or tendons in the foot
- Pregnancy can cause the feet to flatten temporarily due to increased elastin (elasticity) in the body
In order to determine the most appropriate treatment, it is important to identify the type and cause of an individual’s flat feet, through clinical examination and possibly imaging tests (such as x-ray, CT scan, or MRI).
How are flat feet treated?
In most cases conservative treatment is effective in addressing problems caused by flat feet. Conservative treatment options include:
- Recommendations for footwear to provide greater support for flat feet
- Anti-inflammatory measures
- Specific strengthening exercises
As a general rule, custom orthotics provide the best support for treatment of flat feet. Other types of orthotics (such as off-the-shelf orthotics) are also a treatment option, however due to the forces applied by flat feet, custom orthotics are usually found to be more effective in relieving symptoms. Severe cases of flat feet may require the use of ankle foot orthotics (AFOs).
In rare cases, surgery may be indicated to treat severe flat foot that does not respond to conservative treatment.