Foot & Ankle

Morton's Neuroma

Anatomy

Nearly one-fourth of all bones in the human body are in the feet. The foot is a complex, flexible structure that contains bones, joints, and more than 100 muscles, tendons and ligaments, all working together to enable movement and balance. The foot is divided into three sections:

• Forefoot—Has five toes (14 phalanges) and five longer bones (metatarsals). One phalanx of each of the five toes connects to one of the five metatarsals.
• Midfoot—Contains a pyramid-like group of bones, strengthened by tendons, muscles and ligaments to form three curves, or arches (medial, lateral and fundamental longitudinal), at the bottom of the foot. The midfoot includes three cuneiform bones, the cuboid bone, and the navicular bone on top of the midfoot.
• Hindfoot—Includes the heel (calcaneus), which is the largest bone in the foot and ankle. The ankle joint contains a small, irregular-shaped bone (talus) located between the heel, lower leg (fibula) and shinbone (tibia). The talus forms a connection between the leg and foot. The Achilles tendon connects the heel and calf muscle, allowing movement such as running, jumping, and standing on the toes.

Difficulties with foot position and function can lead to more serious problems, not only for the feet, but also for other areas, including the spine. In some cases, these problems may be caused by footwear that fits improperly, does not accommodate normal foot alignment, or that interferes with natural movement and balance of the body.

Description

A benign tumor of a nerve is called a neuroma, however, Morton's neuroma is not actually a tumor—it is a thickening of the tissue that surrounds the digital nerve leading to the toes. Morton's neuroma most frequently develops between the third and fourth toes, and occurs where the nerve passes under the ligament connecting the toe bones (metatarsals) in the forefoot.

Causes

Morton's neuroma usually develops in response to irritation, trauma or excessive pressure.

Symptoms

Persistent pain in the ball of the foot, or a feeling similar to "walking on a marble" are commonly associated with Morton's neuroma. Additional symptoms may include:

• No outward signs—Because this is not actually a tumor, there are typically no outward signs, such as a lump.
• Pain—Burning pain in the ball of the foot that may radiate into the toes; pain generally intensifies with activity or wearing shoes; night pain is rare.
• Toes numbness or discomfort—Numbness or an unpleasant feeling in the toes may be experienced.

Nonsurgical Treatment

Initial therapies for Morton's neuroma are nonsurgical, relatively simple, and may involve one or more of the following:

• Changes in footwear—Avoid high heels and tight shoes. Wearing wider shoes with low heels and soft soles allows the bones of the foot to spread out. This reduces pressure on the nerve and gives the foot time to heal.
• Orthoses—Custom shoe inserts and pads help relieve irritation by lifting and separating the bones, and reducing pressure on the nerve.
• Cortisone (a type of steroid) injections—One or more injections of a corticosteroid medication can reduce the swelling and inflammation of the nerve, bringing some relief from pain.
• Nonsteroidal anti-inflammatory medication (NSAIDs)—Drugs such as ibuprofen or naproxen may help relieve pain, inflammation and swelling. Most people are familiar with nonprescription NSAIDs such as aspirin and ibuprofin, however, whether using over-the-counter or prescription strength, they must be used carefully. Using these medications for more than one month should be reviewed with your primary care physician. If you develop acid reflux or stomach pains while taking an anti-inflammatory, be sure to talk to your doctor.

Several studies have shown that a combination of roomier, more comfortable shoes, nonsteroidal anti-inflammatory medication (NSAID)s, custom foot orthoses, and cortisone injections provide relief in over 80% of people with Morton's Neuroma. If appropriate, a foot and ankle conditioning program may be recommended.

Surgery

If conservative, nonsurgical treatment does not relieve your symptoms, your orthopaedic surgeon may discuss surgical options with you. Surgery may be performed to resect a small portion of the nerve or release the tissue around the nerve, and generally involves a short recovery period.

With any surgery there are some risks, and these vary from person to person. Complications are typically minor, treatable and unlikely to affect your final outcome. Your orthopaedic surgeon will speak to you prior to surgery to explain any potential risks and complications that may be associated with your procedure.