Morton’s Neuroma or Metatarsalgia

Metatarsalgia is the name given to foot pain in the forefoot region, which can be a troublesome and disabling pain problem in the part of the foot bearing the metatarsals. It is not a condition in itself but an indication pointing to an underlying pathology. The types of condition which can cause metatarsalgia include Morton’s neuroma or Morton’s metatarsalgia (a nerve overgrowth is called a neuroma), an inflammatory arthritic condition and nerve inflammation. Anyone can suffer from this pain condition but high impact sports and being middle aged are risk factors.

The forefoot region is the focus of where the stresses are targeted during walking and running, with the first two heads of the metatarsals suffering the greatest forces. During running the metatarsals can endure up to 275 percent of the bodily weight, with estimations made of the foot taking over 100 tons of force over a mile run. The forefoot takes the majority of the burden in activities like running and walking. Inflammatory changes may occur in the little digital nerves supplying the toes, a digital nerve neuritis, caused perhaps by mechanical foot stresses and resulting in foot pain, numbness and pins and needles in the forefoot.

There are typically four women to every man in numbers of sufferers from Morton’s neuroma, being most common in the forties and aggravated by tight footwear. It occurs typically in one foot and most commonly in the third metatarsal interspace between the third and fourth. Under microscopic examination it is likely that no nerve abnormality, such as a nerve overgrowth known as a neuroma, will be shown to explain any of the presenting symptoms. There is a smaller gap between the second and third metatarsals which may make this interspace more likely to develop problems with the nerve.

Wearing shoes with very narrow fronts may elevate the stresses of compression across the metatarsal heads and if high heels are worn this extends the toes and puts the structure under the heads and alongside them under increased tension. Typically patients present with pain with pins and needles over one space between the metatarsals with some referred pain to the toe. Variability of the symptoms over months and years can be considerable with exacerbations on wearing tight footwear and improvement on taking them off. Conservative management concentrates on foot care and on reducing the stresses on the digital nerves.

Foot care may require the patient to alter the type of shoes normally worn but this can be difficult if the patient wants to continue with fashionable footwear. A physiotherapist or a podiatrist can assess and prescribe a metatarsal pad insole or other more complex orthotics. Some patients will find their symptoms eased by conservative strategies like this and accept the result. Local anaesthetic or a corticosteroid can be injected into the painful region but are seldom curative alone. Foot surgery for Morton’s neuroma is variable but a simple approach is to cut the ligament connecting the metatarsal heads and allow the nerve more space, keeping the nerve intact.

A second surgical approach is to remove the nerve from the locally affected area, cutting out the nerve tissue which might be abnormal but a nerve regrowth might occur and form a troublesome neuroma. The difference in success between the two types of operation has not been scientifically shown with both showing about eighty percent reasonable results. After operation the patient will need to limit their weight bearing as they need to, with a steady approach to wearing footwear again. Patients will notice a loss of feeling in the area between the metatarsals if the nerve has been removed but this is rarely a concern.

The operation may not improve the pain condition or there may be a temporary decrease in the symptoms for a period until they worsen again. Decompressing the nerve may leave an irritated nerve intact in the area or cutting the nerve may cause the growth of a neuroma, where the nerve grows abnormally. This can mean that the post-operative symptoms can be more severe than before the operation. The medical establishment cannot agree on the nature of this condition so it continues to be referred to as Morton’s neuroma.

Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Sheffield. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.