What is Morton's Neuroma?

Morton’s neuroma, also known as Morton’s metatarsalgia or interdigital neuroma, is a health condition that involves perineural fibrosis and degeneration of the common digital nerve in the foot. It results from irritation or thickening of one nerve, which can cause severe pain between the toes or on the ball of the foot. It was first described in 1876 and is not a true neuroma, despite resulting in neuropathic pain.

The condition can affect anyone of any gender and age, but is most common among middle-aged women, with a female to male ration of 5:1. This has been linked to the style of footwear worn by these women that put additional pressure and stress on the feet. It is also more common among people that participate in high-impact sports.

Causes

Morton’s neuroma presents as a result of irritation or thickening of a plantar digital nerve located between the toes in the foot, which can occur following several causative factors. These usually involve compression, stretching or damage to the nerves and include:

• Wearing ill-fitting shoes (e.g. tight, pointed-toe or high-heeled shoes)
• Participated in high-impact sporting activities (e.g. running and racquet sports)
• Abnormalities of the foot structures (e.g. flat feet, high arches, bunions or hammertoe)

However, it is unclear if these factors directly Morton’s neuroma or if they increase the risk of an individual who is already susceptible to the disease to experience symptoms.

Symptoms

The primary symptom of Morton’s neuroma is severe pain between the toes or at the base of one or both feet, which can prevent them from moving normally in some cases. If usually affects the area between the third and fourth toes, but other nerves can be affected.

Patients often report a tingling sensation initially, which gradually worsens until it becomes severe and is often described as a sharp, shooting or burning pain. Some patients also report lack of sensation and numbness in their feet, while other describe the pain as similar to walking with a pebble in their shoe.

The pain usually increases in intensity during activities that place pressure on the feet, such as walking or wearing tight-fitting shoes. Conversely, symptoms usually improve if the patient is able to rest or remove the ill-fitting shoes.

Patients may have a flare-up with frequent symptoms over a period of a few weeks, followed by another period of remittance with no evidence of symptoms. Some patients may go for up to a year without experiencing symptoms, although the attacks tend to increase in frequency with time.

Diagnosis

Individuals that report with symptoms of Morton’s neuroma should seek medical advice about the appropriate treatment because the condition is usually chronic and with not subside spontaneously.

The patient consultation should involve a discussion about the symptoms, including the:

• Initiation and duration of symptoms
• Description and progression of pain
• Personal risk factors (e.g. types of shoes work, work or sports activities)

A physical examination and motion tests can be used to diagnose the condition and, in some cases, further diagnostic techniques such as X-ray imaging may be required.

Treatment

The initial treatment of Morton’s neuroma usually involves simple lifestyle changes to eliminate the likely cause of the condition. This may include avoiding wearing ill-fitting shoes, using orthoses to support the foot or reducing participation in high-impact sporting activities. Corticosteroid injections can also help to reduce the pain and inflammation of the nerve, helping to relieve some of the symptoms.

In the majority of cases, more than 8 out of 10 patients, these non-surgical techniques are able to provide sufficient relief. However, some patients will require surgical treatment to resect a portion of the nerve or release some of the surrounding tissues to relieve symptoms.

References

• http://www.nhs.uk/Conditions/mortonsneuroma/Pages/Introduction.aspx
• http://www.mortonsneuroma.com/mortons-neuroma/
• http://emedicine.medscape.com/article/308284-overview#showall
• http://orthoinfo.aaos.org/topic.cfm?topic=a00158