If you sometimes feel that you are "walking on a marble," and you have persistent pain in the ball of your foot, you may have a condition called Morton's neuroma. A neuroma is a benign tumor of a nerve. Morton's neuroma is not actually a tumor, but a thickening of the tissue that surrounds the digital nerve leading to the toes. Morton's neuroma occurs as the nerve passes under the ligament connecting the toe bones (metatarsals) in the forefoot. Morton's neuroma most frequently develops between the third and fourth toes, usually in response to irritation, trauma or excessive pressure. The incidence of Morton's neuroma is 8 to 10 times greater in women than in men.
The exact cause of Morton's neuroma is not known. However, it is thought to develop as a result of long-standing (chronic) stress and irritation of a plantar digital nerve. There are a number of things that are thought to contribute to this. Some thickening (fibrosis) and swelling may then develop around a part of the nerve. This can look like a neuroma and can lead to compression of the nerve. Sometimes, other problems can contribute to the compression of the nerve. These include the growth of a fatty lump (called a lipoma) and also the formation of a fluid-filled sac that can form around a joint (a bursa). Also, inflammation in the joints in the foot next to one of the digital nerves can sometimes cause irritation of the nerve and lead to the symptoms of Morton's neuroma.
Morton's neuroma can cause a very painful burning or sharp pain in your foot that feels worse when you walk. It may feel like a small lump inside the ball of your foot. It is usually between the third and fourth toes, but it can also be between other toes.
The most common condition misdiagnosed as Morton's neuroma is metatarsophalangeal (MTP) joint synovitis. When pain occurs in the third interspace, the clinician may misdiagnose the condition as Morton's neuroma instead of MTP synovitis, which may manifest very much like Morton's neuroma. MTP synovitis is distinguished from Morton's neuroma by subtle swelling around the joint, pain localized mainly within the joint, and pain with forced toe flexion. Palpation of the MTP joint is performed best with a pinching maneuver from the dorsal and plantar aspects of the joint to elicit tenderness of the joint. Other conditions often misdiagnosed as Morton's neuroma include the following. Stress fracture of the neck of the metatarsal. Rheumatoid arthritis and other systemic arthritic conditions. Hammertoe. Metatarsalgia (ie, plantar tenderness over the metatarsal head) Less common conditions that have overlapping symptoms with Morton's neuroma include the following. Neoplasms. Metatarsal head osteonecrosis. Freiburg. steochondrosis. Ganglion cysts. Intermetatarsal bursal fluid collections. True neuromas.
Non Surgical Treatment
Common treatments involve wearing different shoes or using arch supports. Resting the foot, massaging the toes and using an ice pack may work for some people. A GP or a podiatrist (foot specialist) may also recommend anti-inflammatory painkillers or a course of steroid injections. Numbing injections, in which alcohol and a local anaesthetic are injected into the affected area of the foot, may also be effective. In extreme cases, when the condition does not respond to treatment, day case surgery may be needed.
If your pain continues despite several months of conservative treatment, your doctor may recommend surgery to remove the neuroma or to widen the space through which the affected nerve travels. These types of surgery often are done under local anesthesia. If your doctor removes a portion of the affected nerve along with the neuroma, you may develop permanent numbness between the toes.
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).