A Morton neuroma, also called intermetatarsal neuropathy or perineural fibroma, is swelling and growth of tissue surrounding the nerves that pass between the bones of the foot. This growth can be a result of consistent irritation, injury or occur for unknown reasons.
It occurs more commonly in females than in males and is associated with physical activities like running and ballet. While neuroma seems to imply that this is a nerve tumor of the foot, it actually is not a tumor and has no potential of becoming cancerous.
A Morton neuroma occurs because of chronic repeated compression of the nerve that passes between the bones of the foot (metatarsals) against the tissues connecting the bones. Having the toes pointed up causes excessive extension of the joints where the toes meet the foot (metatarsophalangeal joint), which worsens this compression. The toes are commonly in this position in pointed shoes and high-heels. Also, children who were born with foot deformities or muscular disorders can be prone to this condition.
Physicians typically diagnose this condition based on the history and physical exam alone. They may order foot x-rays if there is suspicion of bone injury. Diagnostic ultrasound and MRI can be helpful in visualizing the irritated tissue if the diagnosis is unclear. Nerve studies may also be used to observe the function of the nerves in the feet.
Pain or the sensation that a lump is located at the ball of the foot is usually the first symptom. The pain is made worse when bearing weight or wearing tight-fitting shoes and is often accompanied by numbness or a burning sensation that extends to the toes. While most commonly associated with the space between the third and fourth toes, it can be experienced in other toe spaces and multiple spaces at once. Pain is often relieved when shoes are removed or when the feet are rubbed.
The physician will make treatment decisions with the goal of relieving pressure and irritation of the nerves. Typically, footwear with a wide toe box that will relieve stress on the toes and bones of the foot is recommended; orthotic shoe inserts may also be prescribed. If severe enough, crutches may need to be used to avoid irritation. It is important to avoid shoes with narrow toe-boxes or high heels. Pads may also be placed at the ball of the foot. Avoiding high-impact activities that irritate the neuroma is important while stretching and exercising the muscles of the foot aid in recovery. Anti-inflammatory medications are used to control pain and swelling. In severe cases, injection of steroids may be used to relieve symptoms. If all these methods fail to relieve pain, surgical removal of the tissue may be necessary.
In order to prevent this condition and/or long-term effects, a person should:
It is important to allow the injury to heal completely before resuming activities too quickly. Depending on the injury's severity and a person's healing process, this may vary from a few weeks to several months. The goal is to be able to engage in all sports and activities without pain or causing the condition to return. This can be accomplished by gradually increasing the intensity of activity: