If you sometimes feel that you are “walking on a marble,” and you have persistent pain in the ball of your foot, you may have a condition called Morton’s Neuroma. A Neuroma is a benign tumor of a nerve. Morton’s Neuroma is not actually a tumor, but a thickening of the tissue that surrounds the digital nerve leading to the toes.
Morton’s Neuroma occurs as the nerve passes under the ligament connecting the toe bones (metatarsals) in the forefoot.
Morton’s Neuroma most frequently develops between the third and fourth toes, usually in response to irritation, trauma or excessive pressure.
The incidence of Morton’s Neuroma is 8 to 10 times greater in women than in men.
What causes Morton Neuroma?
Some say that this condition should not be called Morton Neuroma as, in fact, it is not actually a Neuroma. A Neuroma is a non-cancerous (benign) tumour that grows from the fibrous coverings of a nerve. There is no tumour formation in Morton’s Neuroma.
The exact cause of Morton Neuroma is not known. However, it is thought to develop as a result of long-standing (chronic) stress and irritation of a plantar digital nerve. There are a number of things that are thought to contribute to this. Some thickening (fibrosis) and swelling may then develop around a part of the nerve. This can look like a Neuroma and can lead to compression of the nerve.
The anatomy of the bones of the foot is also thought to contribute to the development of Morton’s Neuroma. For example, the space between the long bones (metatarsals) in the foot is narrower between the second and third, and between the third and fourth metatarsals. This means that the nerves that run between these metatarsals are more likely to be compressed and irritated. Wearing narrow shoes can make this compression worse.
Sometimes, other problems can contribute to the compression of the nerve. These include the growth of a fatty lump (called a lipoma) and also the formation of a fluid-filled sac that can form around a joint (a bursa). Also, inflammation in the joints in the foot next to one of the digital nerves can sometimes cause irritation of the nerve and lead to the symptoms of Morton’s Neuroma.
What are the symptoms for Morton Neuroma?
Normally, there are no outward signs, such as a lump, because this is not really a tumor.
Burning pain in the ball of the foot that may radiate into the toes. The pain generally intensifies with activity or wearing shoes. Night pain is rare.
There may also be numbness in the toes, or an unpleasant feeling in the toes.
Runners may feel pain as they push off from the starting block. High-heeled shoes, which put the foot in a similar position to the push-off, can also aggravate the condition. Tight, narrow shoes also aggravate this condition by compressing the toe bones and pinching the nerve.
Who gets Morton Neuroma?
About three people out of four who have Morton’s Neuroma are women. It commonly affects people between the ages of 40 and 50 but can occur at any age.
Poorly fitting or constricting shoes can contribute to Morton’s Neuroma. It is more common in women who habitually wear high-heeled shoes or in men who are required to wear tight (constrictive) footwear. It may also be more common in ballet dancers.
How is Morton Neuroma Diagnosed?
During the examination, your physician will feel for a palpable mass or a “click” between the bones. He or she will put pressure on the spaces between the toe bones to try to replicate the pain and look for calluses or evidence of stress fractures in the bones that might be the cause of the pain. Range of motion tests will rule out arthritis or joint inflammations. X-rays may be required to rule out a stress fracture or arthritis of the joints that join the toes to the foot.
What are the treatment options for Morton Neuroma
If Morton’s Neuroma is diagnosed early, treatment will aim to reduce the pressure on the affected nerve. This is usually the nerve between the third and fourth toe bones (metatarsals).
Here are some recommendation:
- changing the type of shoes you usually wear – shoes with a wider toe area may help ease the pressure on the nerve in your foot
- using orthotic devices – such as a support for the arch of your foot to help relieve the pressure on the nerve
- painkilling medication – anti-inflammatory painkillers or a course of steroid injections into the affected area of your foot may help ease the pain and inflammation
- numbing injections – alcohol and local anaesthetic is injected into your foot using ultrasound for guidance; studies have shown that this type of treatment is effective
- Resting your foot and massaging your toes may also help to relieve the pain. You can make an ice pack by freezing a small bottle of water and rolling it over the affected area.
- Cryotherapy is a non-surgical treatment where very cold temperatures are used to destroy affected nerve tissue and disrupt its blood supply. It can be used to treat Morton’s Neuroma but isn’t widely available in the UK.
If these non-surgical measures do not work, surgery is sometimes needed. Surgery normally involves a small incision (cut) being made on either the top, or the sole, of the foot between the affected toes. Usually, the surgeon will then either create more space around the affected nerve (known as nerve decompression) or will cut out (resect) the affected nerve. If the nerve is resected, there will be some permanent numbness of the skin between the affected toes. This does not usually cause any problems.
You will usually have to wear a special shoe for a short time after surgery until the wound has healed and normal footwear can be used again.
Surgery is usually successful. However, as with any surgical operation, there is a risk of complications. For example, after this operation a small number of people can develop a wound infection. Another complication may be long-term thickening of the skin (callus formation) on the sole of the foot (known as plantar keratosis). This may require treatment by a specialist in care of the feet (chiropody).
What is the outlook (prognosis) for Morton Neuroma?
About one person in four will not require any surgery for Morton’s Neuroma and their symptoms can be controlled with footwear modification and steroid/local anaesthetic injections. Of those who choose to have surgery, about three out of four will have good results with relief of their symptoms.
Recurrent or persisting (chronic) symptoms can occur after surgery. Sometimes, decompression of the nerve may have been incomplete or the nerve may just remain ‘irritable’. In those who have had cutting out (resection) of the nerve (neurectomy), a recurrent or ‘stump’ Neuroma may develop in any nerve tissue that was left behind. This can sometimes be more painful than the original condition.
How to prevent Morton Neuroma?
Ensuring that shoes are well fitted, low-heeled and with a wide toe area may help to prevent Morton’s Neuroma.