It is a condition that affects one of the common plantar digital nerves that run between the metatarsal bones in the foot. It most commonly affects the nerve between the third and fourth metatarsal bones, causing pain and numbness in the third and fourth toes. It can also affect the nerve between the second and third metatarsal bones, causing symptoms in the second and third toes.
Cause of Morton’s Neuroma
The exact cause of Morton’s neuroma is not known. However, it is thought to develop as a result of chronic (long-standing) 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 metatarsals (the long bones of 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.
Symptoms of Morton’s Neuroma
People with Morton’s neuroma usually complain of pain that can start in the ball of the foot and shoot into the affected toes. However, some people just have toe pain. There may also be burning and tingling of the toes. Some people describe the pain that they feel as being like walking on a stone or a marble.
Symptoms can be worse if you wear high-heeled shoes. The pain is relieved by taking your shoe off, resting your foot and massaging the area. You may also experience some numbness between the affected toes.
The symptoms can vary and may come and go over a number of years. Treating Morton’s neuroma earlier will prevent the pain from becoming more regular and persistent.
Morton’s Neuroma Diagnosis
Morton’s neuroma is usually diagnosed by your Chiropodist listening to your symptoms and examining your foot. Sometimes your Chiropodist can feel the ‘neuroma’, or an area of thickening in your foot, which may be tender.
Sometimes, your Chiropodist may suggest an ultrasound or MRI scan to confirm the diagnosis but this is not always necessary. Some doctors inject a local anaesthetic into the area where you are experiencing pain. If this causes temporary relief of pain, burning and tingling, it can sometimes help to confirm the diagnosis and show the doctor where the problem is.
What can a Chiropodist do for you?
Simple treatments may be all that are needed for some people with a Morton’s neuroma. They include the following:
- Footwear adjustments including avoidance of high-heeled and narrow shoes and having special orthotic pads and devices fitted into your shoes.
- Custom made foot orthotics to correct biomechanical faults and reduce pressure on the neuroma.
- Extracorporeal Shockwave therapy
- Calf-stretching exercises may also be taught to help relieve the pressure on your foot.
- Steroid or local anaesthetic injections (or a combination of both) into the affected area of the foot may be needed if the simple footwear changes do not fully relieve symptoms. However, the footwear modification measures should still be continued.
- Sclerosant injections involve the injection of alcohol and local anaesthetic into the affected nerve under the guidance of an ultrasound scan. Some studies have shown this to be as effective as surgery.
If these nonsurgical 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 resect (cut out) the affected nerve. If the nerve is resected (cut out), there will be some permanent numbness of the skin between the affected toes. This does not usually cause any problems.
Surgery is usually successful. However, as with any surgical operation, there is a risk of complications.