Member Case Study: "Painful Metatarsals"

author : AMSSM

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I have been noticing a pain in my left foot on my longer runs. It is focused on the ball part of my foot, almost a burning type sensation. Typically wiggling my toes around will get it to subside.

Question from witteb
I have been noticing a pain in my left foot on my longer runs. Seems to only affect my left, and pretty consistently shows up around the 45-50 minute mark. It is focused on the ball part of my foot, almost a burning type sensation. Typically wiggling my toes around will help get it to subside. I have been noticing this pretty consistently for about the past two months or so. I've been running for a bit over a year, with runs averaging around 30 - 45 minutes. I've been upping the time and my long runs now are typically 60 - 80 minutes. I added a new pair of shoes back at the end of December (Brooks Beast). I have been really focused on training since mid November, typically running 3 days a week, swimming 3 times and biking 3 times.

My first thoughts were that I was curling my toes or tensing them while running, but not sure. Usually once I slow down or stop, the sensation goes away and don't feel anything afterwards. I have "run through it," but usually it doesn't go away completely until I stop running.

Answer

There are just a couple of problems I consider when presented with a patient with the symptoms you have described. The first is metatarsalgia, which is a broad, vague diagnosis to describe “painful metatarsals,” usually at the metatarsal heads (the joints at the base of the toes). The exact cause of pain is uncertain but may be a result of bruising the capsule surrounding the joint or from local injury to the muscles of the foot as they pass through the very dense tissues on the bottom of the foot. The diagnosis is made by reviewing the history and location of pain, and, then, confirming it by reproducing the pain by pressing on the metatarsal joints.

Solutions for metatarsalgia are quite general. Replace running shoes if their total mileage exceeds 400 or 500 miles may be helpful. Running shoes lose 50% of the shock absorption after about 500 miles of use. Icing the symptomatic area for 10-15 minutes after running may reduce pain and local irritation of the tissues. Repetitive use of cold therapy may prevent or minimize any local swelling.

You may also try different models of running shoes. Some shoes may have different degrees of cushioning of the soles and different degrees of rigidity from heel to toe. A more rigid sole may actually increase the forces at the base of the toes during the toe-off phase of running. Metatarsal pads placed just to the heel side of the joints of the toes on the bottom of the foot may also minimize symptoms by changing the distribution of forces across the metatarsal heads. If the metatarsal pads are unsuccessful in reducing symptoms, one may consider a custom orthotic with built-in metatarsal pads. X-rays or other advanced x-ray techniques are often unnecessary to make the diagnosis and initiate treatment. Medications such as ibuprofen may relieve pain, but are unlikely to be a cure.

A second possibility is an interdigital neuroma. This is “doctor speak” for thickened tissue or scar tissue that may put pressure on a nerve that runs between the bones of the foot toward the toes. Typical symptoms are burning, numbness, and/or pain that occur during a run. Running increases blood flow to the exercising muscles of the foot, resulting in swelling of those muscles. This swelling may be enough to compress the nerve causing the “nerve-like” symptoms. Cessation of running relieves symptoms. The treatment of interdigital neuromas can also involve experimenting with running shoes that provide a wider toe box to reduce the compressive forces between the toes. Metatarsal pads may help for the same biomechanical reason they might help treat metatarsalgia.

Failure to improve with these interventions may cause your sports medicine practitioner to try a cortisone injection at the site of the origin of the pain to shrink the thickened tissue that affects the nerve. If a cortisone injection is not effective, an orthopedic surgeon who specializes in problems of the foot and ankle can perform surgery to relieve the pressure on the nerve.

A metatarsal stress fracture can mimic the symptoms of either of these problems and should be a consideration.

It is important to consult a sports medicine practitioner who is familiar with running injuries to insure an accurate diagnosis if none of these actions is successful.

Good luck.

Rob Johnson, M.D.
Member AMSSM

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date: April 2, 2006