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.
The incidence of Morton’s neuroma occurs in four times as many women as men and is more likely in a person’s forties and made worse by ill fitting footwear. Incidence is typical in one foot rather than both and more typically in the third interspace between the metatarsals of the third and fourth. No abnormality of the nerve such as a neuroma, an abnormal grown on a nerve, may be found if the nerve is examined under the microscope, leaving no obvious explanation for the pain. The second and third metatarsals have less room between them anatomically and this may predispose the nerve to problems.
Narrow fronts to shoes can increase the compression between the heads of the metatarsals and in high heels the increased extension of the toes can stretch the nerves under the heads and may increase stresses when walking. Pain and pins and needles in one space between the metatarsals is the commonest symptom with some referral down to the involved toes. Symptoms can vary over a long time, with a worsening on wearing tight shoes and an easing out of footwear. Management involves foot care by reducing the compressive stresses in the forefoot to allow a reduction in pressure on the interdigital nerve.
The shoes normally worn by the patient may be contributing but recommendations to change can be difficult if they want to keep wearing fashionable ones. Assessment and provision of a metatarsal pad or a more complicated orthotic can be performed by a podiatrist or a physiotherapist. Conservative treatment may alleviate the foot symptoms sufficiently for the patient to find the result functionally acceptable. The painful area can be injected with corticosteroid or anaesthetic which is not very effective alone. Morton’s neuroma can be managed by foot surgery and an initial approach cuts the metatarsal ligament to allow sufficient room for the nerve.
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.
After operation there may be persistent symptoms or there may be a period of improvement followed by a recurrence of symptoms. The nerve may stay irritable if the decompression option has been taken and if the nerve has been removed the cut end may grow a neuroma which can be worse than the original presenting problem. A neuroma can be excised to treat this condition in the hope that it will not recur. This foot pain condition continues to be called Morton’s neuroma because there is no general agreement on its cause or its pathology.