Causes And Symptoms Of Morton's Neuroma In The Foot

Introduction

Definition of Morton's neuroma 

Morton’s neuroma is a compressive neuropathy of the nerve between the toes due to compression and constant irritation of a narrow band of tissue that runs across the foot and serves to bundle the ‘toe’ bones together.¹

Brief overview of the condition

Morton’s neuroma, discovered by an American surgeon Thomas George Morton in 1876, is a degenerative neuropathy that usually affects the nerve situated between the third and fourth toe bones of the foot. It is wrongly called neuroma, but actually, it is fibrosis tissue (excess deposit of collagen) of the nerve that thickens and causes a burning pain sensation in the ball of the foot. It mainly occurs in middle-aged women.¹

Causes of Morton's neuroma

The exact cause of Morton’s neuroma is unknown, but current research suggests the main causes are:

Nerve compression between the third and fourth toes

Morton’s neuroma can be caused by a constant compression to the nerve located in the space between your third and fourth metatarsals (long toe bones in the foot). The tissue in this space becomes thicker and thicker over time causing the pain.

Wearing tight or ill-fitting shoes

This condition is known to affect mostly people assigned to females at birth (PAFAB. The prolonged use of elasticated or compression stockings and tight-fitting shoes can be seen as the main contributing factor.

High heels or narrow-toed shoes

High heels and narrow-toed shoes can also contribute to the condition as the ball of the foot is compressed and the nerve is squashed and rubbed against the shoe.

Certain foot deformities or abnormalities

Other factors that may contribute to the development of Morton’s neuroma include foot deformities (e.g., hallux valgus or bunions, hammertoes, etc) caused generally by wearing ill-fitting shoes.²

Symptoms of morton's neuroma

The most common symptoms of Morton’s neuroma include: 

Pain or discomfort in the ball of the foot

This condition causes pain and discomfort in the ball of the foot, between the third and fourth metatarsals when standing or walking

Tingling or numbness in the affected toes 

There may be numbness or an unpleasant tingling (the feeling of pins and needles) in the toes. These episodes of pain can be intermittent.

Feeling as if there's something in the shoe, like a pebble

More than 50% of patients describe the feeling like a ‘pebble’ or a bunched-up sock is inside the shoe and the discomfort usually gets worse over time.

Burning or shooting pain that radiates from the ball of the foot to the toes

The pain may worsen and radiate from the ball to the arch or top of the foot. If the thickening enlarges, the toes might become crooked or spread apart.

Worsening of symptoms with activity or prolonged standing

Morton’s neuroma symptoms can get worse over time as the nerve becomes larger.³ High impact activities, such as running, and prolonged hours of standing mayl make the symptoms worse.

Diagnosis of morton's neuroma

Morton’s neuroma diagnosis begins with a thorough patient history by a healthcare professional, like where the patient feels pain, the duration of the symptoms and the character of the symptoms. During the exam, the healthcare professional will press on your foot to feel for a lump or sore spot.

The best diagnosis of Mornon’s neuroma is through imaging tests, using MRI, CT scanning, and ultrasonography. Although the available evidence suggests that ultrasound is more accurate than MRI for the diagnosis of this condition, MRI may also detect other causes of forefoot pain, for example abnormalities of the bone (such as oedema, fracture, erosion and cyst) and perhaps rule out alternative diagnoses.³

The doctors can confirm the nerve injury by injecting an anesthetic into the area of pain and see how successful the anesthetic is relieving the pain.⁴

Treatment options for Morton's neuroma

There are different treatments available for Morton’s neuroma. It is recommended to visit a healthcare professional, such as a podiatrist, for advice on the right treatment.

Non-surgical treatments

There are several non-surgical treatments for Morton’s neuroma, and the optimal one depends on individual characteristics of the condition. For example using heat to treat the nerve (radiofrequency ablation); steroids or alcohol injections if other treatments are not working and you have severe symptoms.⁴

Surgical interventions

If the quality of life has been reduced because the pain is severe and the non-surgical treatment has not been successful, a good option might be surgery. Surgical interventions of Morton’s neuroma results in good clinical results and high overall patient’s satisfaction in the long term.⁵

Prevention and self-care tips

There are several ways you can help prevent developing Morton’s neuroma:

Choose appropriate footwear

Footwear changes such as switching to wide shoes with a low heel would be helpful as there may not be as much pressure on the affected nerve as narrower shoes. Don’t wear tight or high-heeled shoes for long periods. 

Wear shoe inserts or orthotics for better support

Shoe pads and inserts can also relieve the pressure, cushion the ball of the foot and keep the toes in the correct position.

Avoid repetitive high-impact activities

If you are in pain, try to avoid high-impact activities such as running and racquet sports.

This kind of activity can make the symptoms worse as the nerve is overstimulated by rubbing and pressure. 

Take regular breaks during activities

Taking regular breaks during activities is encouraged as this can reduce any inflammation in the area.

Maintain a healthy weight

Research shows that reaching and maintaining a healthy weight (this may involve losing weight) reduces the amount of pressure on the foot. 

When to seek medical attention

You should seek advice from a healthcare professional when you have any of the following:

Persistent or worsening symptoms

Morton’s neuroma symptoms usually get worse over time. Minor pain comes and goes with rest or after shoes are removed and the foot is massaged. If a neuroma is not treated, it can cause nerve damage or chronic pain in the affected foot. 

Difficulty walking or performing daily activities

When the condition interferes with your life and daily activities and you take pain medicine, it is highly recommended to visit a doctor.

Severe pain or swelling in the foot 

If the pain gets worse and/or you notice your foot is swollen, ask for medical attention.

Summary

Morton’s neuroma is a neurological condition which involves the nerve situated between the 3rd and 4th metatarsal. It mainly affects individuals who wear restricted or high-heeled footwear for long periods of time. The severity of the condition is not the same for everyone, and it tends to worsen over time. When the pain is not severe, there are many treatment options, such as changing shoes, using specific insoles, avoiding heels, and avoiding impact activities. When the pain is severe and is left untreated, it may lead to further symptoms of pain in the foot and calf. Surgical treatment for Morton’s neuroma which involves excision of the neuroma is considered if conservative management is not successful.