Definition
Morton’s neuralgia, more commonly called Morton’s neuroma, is a condition in which a nerve between the metatarsal heads becomes swollen causing pain felt in the ball of the foot and radiating into the toes. It is usually made worse by wearing tight shoes and better by taking them off.
Morton’s neuroma is usually caused by repetitive minor trauma to the nerve, often as a result of overuse, in runners, for example, or by abnormal mechanics in the foot.
Diagnosis
Your doctor can usually diagnose Morton’s neuroma clinically from your symptoms, but ultrasound or MRI scans can be useful to confirm the diagnosis and exclude other problems such as mechanical capsulitis of the lesser MTP joints.
Treatment
Morton’s neuromas are not fundamentally harmful and treatment is therefore usually aimed at relieving the symptoms rather than removing the neuroma.
Conservative measures such as wider shoes, orthotics (insoles) with a metatarsal bar or pad, pain killers and physiotherapy to improve the mechanics of the foot may help to reduce the pain.
Injections of steroid with local anaesthetic often shrink the neuroma and relieve the pain, as well as playing a useful role in confirming the diagnosis if this is in any doubt.
Injection of concentrated alcohol or cold burns with cryotherapy have also been used to kill the swollen nerve but these techniques can cause damage and painful scarring in neighbouring tissuess.
Surgical treatment should be considered if conservative measures have not relieved the neuroma symptoms.
Most commonly, surgery for Morton’s neuroma consists of removing the swollen, damaged, nerve and burying the nerve stump in the nearby small muscles. This can be performed through an incision in either the sole or dorsum (top) of the foot, but the dorsal approach is usually preferred as it avoids the potential complications of walking on a scar.
There is some evidence that decompressing the nerve without removing it can be just as effective but this technique has not yet been widely adopted.