Mortons Neuroma or Metatarsalgia
Foot pain in the forefoot, which can be an annoying and persistent pain in the frontal foot region, is medically known as metatarsalgia due to the metatarsal region being the main area of pain. Metatarsalgia is not a specific condition but rather a symptom of some other condition. Metatarsal pain can be caused by a series of problems which include nerve inflammation, inflammatory arthritis or a nerve outgrowth called a neuroma (Morton''s neuroma or Morton''s metatarsalgia). This condition can present in anybody but is more likely in middle-aged people and anyone pursuing high impact sporting activities.
In the actions of running and walking the body weight is transferred forwards from the rear foot to the forefoot and the first two metatarsal heads receive the majority of the force. Up to 275% of the weight of the body can be applied to the metatarsals in running, with an estimated load of over a hundred tons per foot on running a mile. The main loaded areas during fast moving and running is the forefoot. The small digital nerves running to the toes can develop inflammation, called neuritis, secondary to the biomechanical loads applied to the foot, resulting in foot pain, pins and needles and numbness.
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.
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.
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.
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.