A Morton’s neuroma, or interdigital neuroma, is a painful condition which involves a nerve on the plantar aspect (bottom) of the foot. Occasionally a neuroma develops following a bruising injury to the sole of the foot, such as might be caused by jumping onto a rock or other objects, but in general, the origin of the condition is unknown.
Poorly fitted footwear can be a cause. Shoes that have a tight and narrow toe box can cause the never to become entrapped causing the pain. High heeled shoes abnormally place the metatarsals under extreme pressure which can cause Morton?s Neuroma. In cases of abnormal pronation, there can be significant motion between the 3rd and 4th metatarsals which can cause an irritation to the nerve that runs between them. This inflammation causes the pain.
There may be pain at the end of the push-off phase when walking or running, and this pain is generally worse when the client is wearing shoes as opposed to being barefoot. Clients may also report a relief of symptoms by massaging the foot, which may spread the metatarsal heads and mobilize the entrapped nerve.
In some cases your doctor will be able to feel the Morton’s as a swelling in the middle of your foot. However they may also suggest an X-ray or a blood test – this is normally to rule our other causes of the pain such as arthritis. The most accurate way to diagnose Morton?s itself is with magnetic resonance imaging (MRI) or ultrasound.
Non Surgical Treatment
You may need a metatarsal pad if wider shoes do not help relieve your Morton?s neuroma symptoms. A metatarsal pad will help spread your metatarsal bones and reduce pressure on your affected nerve as it travels under the ball of your foot. The placement of your metatarsal pad is important, and it is best placed by a foot care professional who has experience in the anatomy of the forefoot and Morton?s neuroma treatment.
Patients are commonly offered surgery known as neurectomy, which involves removing the affected piece of nerve tissue. Postoperative scar tissue formation (known as stump neuroma) can occur in approximately 20%-30% of cases, causing a return of neuroma symptoms. Neurectomy can be performed using one of two general methods. Making the incision from the dorsal side (the top of the foot) is the more common method but requires cutting the deep transverse metatarsal ligament that connects the 3rd and 4th metatarsals in order to access the nerve beneath it. This results in exaggerated postoperative splaying of the 3rd and 4th digits (toes) due to the loss of the supporting ligamentous structure. This has aesthetic concerns for some patients and possible though unquantified long-term implications for foot structure and health. Alternatively, making the incision from the ventral side (the sole of the foot) allows more direct access to the affected nerve without cutting other structures. However, this approach requires a greater post-operative recovery time where the patient must avoid weight bearing on the affected foot because the ventral aspect of the foot is more highly enervated and impacted by pressure when standing. It also has an increased risk that scar tissue will form in a location that causes ongoing pain.
Although the exact causes of neuromas are not completely known, the following preventive steps may help. Make sure your exercise shoes have enough room in the front part of the shoe and that your toes are not excessively compressed. Wear shoes with adequate padding in the ball of the foot. Avoid prolonged time in shoes with a narrow toe box or excessive heel height (greater than two inches).