This is a painful condition affecting a small nerve in the foot. It occurs when the five long bones that run the length of the foot get pushed together, pinching the nerve in between. This friction on the nerve causes it to thicken and inflame causing pain. The condition gets its name from an American surgeon, George Morton.
A Morton?s Neuroma are a result of complex biomechanical changes that occur in your feet. There are a number of theories as to the exact cause of the scarring and thickening, but it basically boils down to overload of the tissue structure. The body lays down scar tissue to try to protect the overloaded structure. Tight-fitting shoes may exacerbate a Morton?s Neuroma. Shoes such as high heels and shoes with tight toe boxes (eg womens fashion shoes and cowboy boots) are particularly damaging to the toes. These shoes have a sloping foot bed and a narrow toe box. The slope causes the front of the foot to bear your weight. The angle of the toe box then squeezes your toes together. Footwear is not the only cause of a Morton?s Neuroma. Injuries to the foot can also be a factor in developing the condition by changing your foot biomechanics. Poor foot arch control leading to flat feet or foot overpronation does make you biomechanically susceptible to a neuroma.
The symptoms of Morton?s Neuroma tend to come and go over time. They are typically exacerbated by physical activity or by wearing certain shoes. Morton?s Neuroma symptoms include sharp pain in the ball of the foot, pain radiating to the tips of the toes, burning pain in the second, third, or fourth toes, numbness in the toes, sensation of a lump between the toes.
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
Simple treatments may be all that are needed for some people with a Morton's neuroma. They include the following. Footwear adjustments including avoidance of high-heeled and narrow shoes and having special orthotic pads and devices fitted into your shoes. Calf-stretching exercises may also be taught to help relieve the pressure on your foot. Steroid or local anaesthetic injections (or a combination of both) into the affected area of the foot may be needed if the simple footwear changes do not fully relieve symptoms. However, the footwear modification measures should still be continued. Sclerosant injections involve the injection of alcohol and local anaesthetic into the affected nerve under the guidance of an ultrasound scan. Some studies have shown this to be as effective as surgery.
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.
Wearing proper footwear that minimizes compression of the forefoot can help to prevent the development of and aggravation of a Morton's neuroma.