plantar fibromaIf you have found a lump in your arch, more than likely you have developed a plantar fibroma. A plantar fibroma (also known as plantar fibromatosis) is a benign growth or nodule, really a thickening, of the plantar fascia – a thick ligament in the bottom of your foot. If you have found a bump or lump in your arch, make an appointment to see us in our Seattle foot and ankle clinic. 

Cause of Plantar Fibromas

No one is quite sure of the cause of plantar fibomas, but there is evidence that trauma to the plantar fascia may cause them to form. The most common type of trauma is simply over-stretching of the plantar fascia due to the arch flattening too much. When the arch flattens, the foot gets longer and this stretches the fascia. In some people this excessive stretching can lead to formation of fibromas.

Are Plantar Fibromas Painful?

The fibroma itself doesn’t cause pain, but pressure on the lump can lead to pain in the arch when walking or standing.


We can usually diagnose the lumps in your arch by examining your foot. If further information is required we can visualize the mass using diagnostic ultrasound in our office.

Treatment of Plantar Fibromas

Custom Orthotics

Custom orthotics are the most effective treatment for plantar fibromas. Orthotics must accomplish two things to best treat this problem:

  1. Decrease tension on the plantar fascia
  2. Decrease pressure on the lump in your arch

To decrease tension, we prescribe an orthotic that hugs your arch very close – this is called a total contact orthotic. By aggressively supporting your arch, we prevent the foot from flattening and decrease tension on the plantar fascia.

We have to be very careful, however, because an orthotic that hugs your arch very close could irritate the plantar fibroma. To prevent this, we have an indentation or pocket added to the orthotic exactly in the location of the fibroma. This acts to distribute pressure off of the lump.

We are experts in providing orthotics that are both extremely effective and comfortable. Make an appointment today to see us in our Seattle clinic. 

Other Treatments

  • Injections: Injection of steroid into the fibroma has not been found to be very effective.
  • Surgery: Surgical removal has also not been found to be very effective. The surgery itself has some significant side effects including flattening of the arch due to weakening of the plantar fascia. In addition, there is an extremely high likelihood of recurrence of the fibroma. We do not recommend surgery except in cases where nothing else has helped and there is significant pain.
  • Topical Medication: There is one topical prescription cream that has been shown in a single study to help reduce plantar fibromas. We think that more study is needed to determine it’s true effectiveness, but we can discuss this with you at your appointment.
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