Pain in the ball of your foot? Tingling and numbness in your toes? The constant feeling of a stone in your shoe? You may have a Morton's neuroma.
What is a neuroma?
A neuroma is a benign (non-cancerous) tumour of a peripheral nerve. They are often caused by nerve injuries such as direct pressure or repetitive trauma or can form at the end of a cut nerve. Less often multiple neuromas can form due to a genetic condition known as neurofibromatosis, but we will not be covering this.
What is Morton's neuroma?
Mortons' neuroma, first described by Thomas Morton in 1876, is a painful condition that affects the ball of the foot. Compression or irritation of a digital nerve in the space between the foot bones (intermetatarsal space), typically between the 2nd and 3rd or third and fourth toes, causes the sheath surrounding a nerve to become inflamed and over time develop into a lump.
What causes Morton's neuroma?
There are a number of risk factors that may predispose you to develop Morton's neuroma. All of these in essence cause compression or irritation of the digital nerve in the intermetatarsal space:
Footwear - One of the main offenders is wearing narrow shoes that stop your foot from expanding when you walk or high-heeled shoes that force your toes into the toe box.
Foot shape - Certain foot deformities like having a bunion, hammertoes, flat feet or having flexible feet increases your risk of developing a neuroma.
Exercise - High-impact activities like running, walking long distances on hard surfaces, or standing for long periods of time may not only cause a neuroma but if present will bring on the symptoms.
Weight - Carrying excessive weight, either in you (obesity) or on you (weights), puts additional stress on your feet.
What does Morton's neuroma feel like?
Typical neuroma symptoms people report is the feeling of having a marble or pebble in their shoe when there isn't one. You may get a pain in the ball of the foot when standing or walking. You may even experience tingling, burning or numbness in the toes. These symptoms tend to improve when you take off your footwear or you're off your feet.
Diagnosis of Morton's Neuroma
The diagnosis is made from your medical history and physical examination when we attempt to reproduce your symptoms.
Ultrasound imaging done during your appointment can confirm the position and size of a neuroma.
X-rays may be requested to look for other possible causes of foot pain like a metatarsal bone stress fracture or joint arthritis
Magnetic resonance imaging (MRI) is occasionally used in cases that have failed initial conservative management to look for other possible causes. The common alternative diagnosis is intermetatarsal bursitis, an enlarged fluid-filled sac in the same area causing irritation and inflammation of the nerve.
Treatment options for Morton's neuroma
More than 80% of people with Morton's neuroma will improve without the need for surgery.
The first line of treatment focuses on non-operative methods, many of which you can try yourself:
- Activity modification - Cut back on the activities that trigger your symptoms. ok to cut back
- Shoe modifications - Wide fitting shoes are preferable. Avoid wearing shoes with narrow toe boxes or high heels.
- See a podiatrist to provide padding or a custom orthotic/insoles to support the metatarsal arch to reduce pressure on the nerve.
- Injection - An injection is administered under ultrasound guidance into the fibrotic tissue around the nerve. The most common substrate used is a cortisone injection but alcohol injections are also done.
- Radiofrequency ablation or cryoablation - Burning or freezing the nerve to stop it from transmitting pain signals.
- Surgery - If you do not respond sufficiently to a non-surgical approach you will be referred to a foot and ankle surgeon to have a discussion about removing the neuroma.
It is best to see a specialist as soon as you start to get symptoms of Morton's neuroma. An early diagnosis lessens the need for more invasive treatments. Click here if you wish to schedule an appointment.