The Pain In Your Foot Could Be Plantar Fibroma

Should you be running if you feel a knot on the bottom of your foot?

A recent study published in Orthopedic Research and Reviews characterizes plantar fibroma as an “uncommon and challenging disorder.” 

Plantar fibroma is the name of a nodule, growth, triggerpoint, or knot embedded in the plantar fascia on the bottom of the foot. The plantar fascia is the band of tissue that is under the bottom of the foot, extending from the toes to the heel. The condition is caused when the plantar fascia tightens up. 

You may be familiar, as a runner, with plantar fasciitis. But Dr. Scott Nelson, president of the American College of Foot and Ankle Surgeons, notes that the two disorders are different. “[Plantar fasciitis] is an inflamed tissue and not associated with a mass being present,” he says. 

A 2018 genetic study conducted at Stanford University Medical Center showed an association with DNA variants that could explain why some people are more likely to have plantar fascial problems (including both plantar fasciitis and plantar fibroma). But overall, the cause of plantar fibroma specifically is widely debated. “There are differing opinions in the literature about trauma being a causative force,” says Dr. Priya Parthasarathy, a board-certified podiatrist. “Some patients on Dilantin [an anti-convulsive medicine] can develop nodules. Also some comorbidities such as epilepsy, alcoholism, liver cirrhosis, hypothyroidism, and diabetes mellitus may have an increased incidence of plantar fibroma.” 

Plantar Fibroma Symptoms

Rebecca Goldstein, physical therapist with Professional Physical Therapy, says the symptoms can include:

  • Tightness on the bottom of the foot
  • Pain and stiffness with walking
  • Morning stiffness when taking that first step out of bed
  • Calf tightness
  • Pain when walking barefoot

Goldstein adds that a tight Achilles or calf muscles or improper footwear with not enough arch support may trigger plantar fibroma. “Over time your plantar fascia may tighten up,” she says. 

“Stretching the calf and foot is very important after running,” says Dr. Parathasarathy, as a way of preventing plantar fibroma. 

If you start to notice a nodule develop on the bottom of your foot, Dr. Parathasarathy recommends you make an appointment to see an expert. Both Dr. Parathasarathy and Dr. Nelson say that if the growth is not causing you pain, it’s OK to continue to run on it. “If you notice the nodule grows in size and hurts to run on it, then stop running,” she says. Seek treatment and wait for the foot to heal. 

You should take time off when you experience any sort of foot pain. If not, you may compensate your foot strike, which can lead to other injuries: hip, knee, or low-back pain. 

Your provider may be able to diagnose plantar fibroma by feeling the enlarged mass, however, “the growth is sometimes evaluated with an X-ray to make sure there are no bone changes or soft tissue calcification,” says Dr. Nelson. 

What’s the recovery time?

A few weeks is the typical treatment time for plantar fibroma. Massaging the foot with a foam roller, tennis ball, or frozen water bottle can help release tension in the foot. Stretching the foot is important too. It can lengthen the tissues and increase circulation. Physical therapy is a treatment option that breaks down the buildup of fibers and growths. Physical therapists use effective stretching with strength exercises to treat the condition.

A podiatrist may prescribe a topical medication to reduce the nodule size or give you a corticosteroid injection to help with the pain. They can also help fit you with custom orthotics to offload the pressure on the nodules. 

And remember, before you start any at-home treatment program, always speak with your doctor for proper diagnosis.