A bunion is an abnormal enlargement of the joint (the first metatarsophalangeal joint, or MTPJ) at the base of the great or big toe (hallux). It is caused by inflammation and usually results from chronic irritation and pressure from poorly fitting footwear.
Description
A displacement of two major bones of the foot (hallux valgus) causes bunions, although not everyone with this displacement will develop the joint swelling and bone overgrowth that characterize a bunion. One of the bones involved is called the first metatarsal bone. This bone is long and slender, with the big toe attached on one end and the other end connected to foot bones closer to the ankle. This foot bone is displaced in the direction of the four other metatarsals connected with the toes. The other bone involved is the big toe itself, which is displaced toward the smaller toes. As the big toe continues to move toward the smaller toes, it may become displaced under or over the second toe. The displacement of these two foot bones causes a projection of bone on the inside portion of the forefoot. The skin over this projection often becomes inflamed from rubbing against the shoe, and a callus may form.
The joint contains a small sac (bursa) filled with fluid that cushions the bones and helps the joint to move smoothly. When a bunion forms, this sac becomes inflamed and thickened. Inflammation of the bursa is called bursitis. The swelling in the joint causes additional pain and pressure in the toe.
Bunions can also form on the bones that attach the little toe to the foot (the fifth metatarsal bone). These bunions are called tailor's bunion or bunionette.
Causes & symptoms
Bunions may form as a result of abnormal motion of the foot during walking or running. One common example of an abnormal movement is an excessive amount of stress placed upon the inside of the foot. This leads to friction and irritation of the involved structures. Age has also been noted as a factor in developing bunions, in part because the underlying bone displacement worsens over time unless corrective measures are taken.
Wearing improperly fitting shoes, especially those with a narrow toe box and excessive heel height, often causes the formation of a bunion. This forefoot deformity is seen more often in women than men. The higher frequency in females may be related to the strong link between footwear fashion and bunions. In fact, in a recent survey of more than 350 women, nearly 90% wore shoes that were at least one size too small or too narrow. Shoes without proper arch supports contribute to bunions, since they allow the foot to roll inward (pronate,) putting more pressure on the joint of the big toe.
Because genetic factors can predispose people to hallux valgus bone displacement, a strong family history of bunions can increase the likelihood of developing this foot disorder. Various arthritic conditions and several genetic and neuromuscular diseases, such as Down syndrome and Marfan syndrome, cause muscle imbalances that can create bunions from displacement of the first metatarsal and big toe. Other possible causes of bunions are leg-length discrepancies (with the bunion present on the longer leg) and trauma occurring to the joint of the big toe. Persons with flat feet or gout are at increased risk for developing bunions.
Symptoms of bunions include the common signs of inflammation such as redness, swelling, and pain. The discomfort is primarily located along the inside of the foot just behind the big toe. Because of friction, a callus may develop over the bunion. If an overlapping of the toes is allowed, additional rubbing and pain occurs. Inflammation of this area causes a decrease in motion with associated discomfort in the joint between the big toe and the first metatarsal. If allowed to worsen, the skin over the bunion may break down causing an ulcer, which also presents a problem of potential infection. (Foot ulcers can be particularly dangerous for people with diabetes, who may have trouble feeling the ulcer forming and healing if it becomes infected.)
Diagnosis
A thorough medical history and physical exam by a physician is always necessary for the proper diagnosis of bunions and other foot conditions. X rays can help confirm the diagnosis by showing the bone displacement, joint swelling, and, in some cases, the overgrowth of bone that characterizes bunions. Doctors will also consider the possibility that the joint pain is caused by or complicated by arthritis (which causes destruction of the cartilage of the joint), gout (which causes the accumulation of uric acid crystals in the joint), tiny fractures of a bone in the foot (stress fractures), or infection, and may order additional tests to rule out these possibilities.
Treatment
The first step in treating a bunion is to remove as much pressure from the area as possible. A foam-rubber pad may be worn at night while sleeping to separate the big toe from the other toes. Various taping techniques can be useful to realign the toe and decrease friction and rubbing that may be present. Most patients are instructed to rest or choose exercises that put less stress on their feet, at least until the misalignment is corrected.
Persons with bunions should wear shoes that have enough room in the toe box to accommodate the bunion. High-heeled shoes and tight-fitting socks or stockings should be avoided. Sandals are a good choice. Shoes may be stretched to provide more comfort or customized to relieve pressure on the affected area. Shoes should be removed periodically during the day to give feet a break. Dressings and pads help protect the bunion from additional shoe pressure. Arch supports can reduce the pressure on the bunion. The application of splints or customized shoe inserts (orthotics) to correct the alignment of the big toe joint is effective for many bunions. These can correct the excessive pronation (turning inward) so that the pressure is not continually on the big toe.
Deep friction massage techniques by a physical or massage therapist can be helpful to increase circulation, reduce inflammation, and prevent soft tissue build-up. Physical therapy also provides useful approaches, such as ultrasound, to help retard or reverse the formation of the bunion.
One study found that using an extract from marigold (Tagetes patula) with a protective pad led to a reduction in the size and pain of bunions. A used chamomile tea bag applied to a bunion may be helpful. Massaging with essential oil of chamomile or with a cream containing chamomile may provide relief. The homeopathic remedyCalcarea phosphorica can be useful in balancing the bone formation and remodeling.
Soaking the affected foot in warm water may reduce pain. Elevating the affected foot and applying ice and compression to the bunion can be helpful, especially after exercise.
Dietary supplements and dietary changes may help to treat bunions. Vitamins which may be helpful in treating the bursitis associated with bunions include A, B complex, C, and E. Increasing the intake of protein may also be beneficial.
Acupuncture can be useful in treating the symptoms as the spleen meridian is roughly where the pain occurs. Other treatments may help stabilize the foot.
If conservative treatments are not successful, surgical removal of the bunion may be necessary to correct the deformity. This procedure is called a bunionectomy, and there are many variations on the operation, which is usually performed by a surgeon who specializes in treating bone conditions (orthopedics) or by one who specializes in treating the foot (podiatry). The procedure chosen depends upon the angle of the bone misalignment, condition of the bursa, and strength of the bones. Most bunionectomies involve the removal of a section of bone and the insertion of pins to rejoin the bone. Sometimes the surgeons may move ligaments (which connect bone to bone in the joint) or tendons (which connect bone to muscle) in order to realign the bones.
Expected results
Often, modifications in footwear allow a good recovery without a need for surgery. If surgery is necessary, complete healing without complications requires approximately four to six weeks. Even after surgery corrects the bone misalignment, patients are usually instructed to continue wearing low-heeled, roomy shoes to prevent the bunion from reforming. Complications of bunions include infection of the bunion and inflammation and arthritic changes in other joints as a result of difficulty in walking.
Prevention
Prevention begins with proper foot wear. Shoes with a wide and deep toe box are best. High-heeled shoes should not be worn for longer than three hours at a time. If a bunion is present and becomes inflamed, the foot should be elevated with the application of an ice pack over the painful area for not more than 20 minutes every other hour. Daily exercise strengthens the muscles of the legs and feet and may prevent bunion formation. Women who wear high-heeled shoes should do calf stretches on a regular basis. Use of arch supports or custom made orthotics can help people whose feet rotate inward as they walk or those with different leg lengths. Stretching the Achilles tendon can counteract stresses on the forefoot.
BOOKS
Richard B. Birrer, et al. Common Foot Problems in Primary Care, 2nd ed. Philadelphia, PA: Hanley & Belfus, Inc., 1998.
PERIODICALS
Cimons, Marlene. "Bothersome Bunions." Runner's World 34 (May 1999): 46+.
ORGANIZATIONS
American Orthopedic Foot and Ankle Society. 222 South Prospect, Park Ridge, IL 60068.
American Podiatry Medical Association. 9312 Old Georgetown Road, Bethesda, MD 20814.
