Also known as Morton's Interdigital Neuroma, Morton's Metatarsalgia, Morton's Neuralgia, Plantar Neuroma, Intermetatarsal Neuroma) What is a Morton's neuroma? Morton's neuroma is a condition characterized by localized swelling of the nerve and soft tissue located between two of the long bones of the foot (metatarsals - figure 1), which can result in pain, pins and needles, or numbness in the forefoot or toes.
A Morton's neuroma commonly occurs due to repetitive weight bearing activity (such as walking or running) particularly when combined with tight fitting shoes or excessive pronation of the feet (i.e. "flat-feet"). The condition is also more common in patients with an unstable forefoot allowing excessive movement between the metatarsal bones. A Morton's neuroma can also occur due to certain foot deformities, trauma to the foot, or the presence of a ganglion or inflamed bursa in the region which may place compressive forces on the nerve.
Symptoms include: pain on weight bearing, frequently after only a short time. The nature of the pain varies widely among individuals. Some people experience shooting pain affecting the contiguous halves of two toes. Others describe a feeling like having a pebble in their shoe or walking on razor blades. Burning, numbness, and paresthesia may also be experienced. Morton's neuroma lesions have been found using MRI in patients without symptoms.
The physician will make the diagnosis of Morton's neuroma based upon the patient's symptoms as described above in an interview, or history, and a physical examination. The physical examination will reveal exceptional tenderness in the involved interspace when the nerve area is pressed on the bottom of the foot. As the interspace is palpated, and pressure is applied from the top to the bottom of the foot, a click can sometimes be felt which reproduces the patient's pain. This is known as a Mulder's sign. Because of inconsistent results, imaging studies such as MRI or ultrasound scanning are not useful diagnostic tools for Morton's neuroma. Thus the physician must rely exclusively on the patient's history and physical examination in order to make a diagnosis.
Non Surgical Treatment
Conservative treatment involves a reduction in the inflammation and removing the impingement factor. Reduction in inflammation is achieved via rest, elevation, ice, and massage with anti-inflammatory gels. Removing foot wear and and/r wearing broad type footwear would also help. Injection therapy is useful in reducing symptoms but not very successful in providing long term relief. The only time when it is most appropriate is when the cause of the space occupying object is not a neuroma but an inflamed bursa. Injection would help to relieve symptoms, and often cortisone is not even necessary.
The ultimate success of a Morton?s neuroma treated surgically is somewhat unclear. This is likely due to the idea that in most instances a ?Morton?s neuroma? is actually more than just an isolated nerve problem but rather consitutes a metatarsalgia where other structures (such a as the MTP joints) are also problematic, not just the nerve. Therefore, addressing the nerve as well as the other components of a metatarsalgia may offer a better chance of surgical success. However, like many conditions in foot and ankle, it is ideal if this condition can be managed without surgery.