Bunion Deformity
One of the more common conditions treated by podiatric surgeons is the painful bunion. Patients with this condition will usually complain of pain when wearing certain shoes, especially snug-fitting dress shoes, or with physical activity, such as walking or running. Bunions are most commonly treated by conservative means. This may involve shoe gear modification, padding, and orthoses. When this fails to provide adequate relief, surgery is often recommended. There are several surgical procedures to correct bunions. Selection of the most appropriate procedure for each patient requires knowledge of the level of deformity, a review of the x-rays, and an open discussion of the goals of the surgical procedure. Almost all surgical procedures require cutting and repositioning the first metatarsal. In the case of mild to moderate bunion deformities, the bone cut is most often performed at the neck of the metatarsal (near the joint).
Cause of Bunion Deformity
The classic bunion, medically known as hallux abductovalgus or HAV, is a bump on the side of the great toe joint. This bump represents an actual deviation of the 1st metatarsal and often an overgrowth of bone on the metatarsal head. In addition, there is also a deviation of the great toe toward the second toe. In severe cases, the great toe can either lie above or below the second toe. Shoes are often blamed for creating these problems. This, however, is inaccurate. It has been noted that primitive tribes where going barefoot is the norm will also develop bunions. Bunions develop from abnormal foot structure and mechanics (e.g. excessive pronation), which place an undue load on the 1st metatarsal. This leads to stretching of supporting soft tissue structures such as joint capsules and ligaments with the end result being gradual deviation of the 1st metatarsal. As the deformity increases, there is an abnormal pull of certain tendons, which leads to the drifting of the great toe toward the 2nd toe. At this stage, there is also an adaptation of the joint itself that occurs.
Symptoms Related to Bunion Deformity
The most common symptoms associated with this condition are pain on the side of the foot. Shoes will typically aggravate bunions. Stiff leather shoes or shoes with a tapered toe box are the prime offenders. This is why bunion pain is most common in women whose shoes have a pointed toe box. The bunion site will often be slightly swollen and red from the constant rubbing and irritation of a shoe. Occasionally, corns can develop between the 1st and 2nd toe from the pressure the toes rubbing against each other. On rare occasions, the joint itself can be acutely inflamed from the development of a sac of fluid over the bunion called a bursa. This is designed to protect and cushion the bone. However, it can become acutely inflamed, a condition referred to as bursitis.
Treatment of Bunion Deformity
Early treatment of bunions is centered on providing symptomatic relief. Switching to a shoe with a rounder, deeper toe box and made of a softer more pliable leather will often provide immediate relief. The use of pads and cushions to reduce the pressure over the bone can also be helpful for mild bunion deformities. Functional foot orthotics, by controlling abnormal pronation, reduces the deforming forces leading to bunions in the first place. These may help reduce pain in mild bunion deformities and slow the progression of the deformity. When these conservative measures fail to provide adequate relief, surgical correction is indicated.The choice of surgical procedures (bunionectomy) is based on a biomechanical and radiographic examination of the foot. Because there is actual bone displacement and joint adaptation, most successful bunionectomies require cutting and realigning the 1st metatarsal (an osteotomy). Simply “shaving the bump” is often inadequate in providing long-term relief of symptoms and in some cases can actually cause the bunion to progress faster. The most common procedure performed for the correction of bunions is the 1st metatarsal neck osteotomy, near the level of the joint. This refers to the anatomical site on the 1st metatarsal where the actual bone cut is made. Other procedures are performed in the shaft of the metatarsal bone (see procedures performed in the shaft of the metatarsal) and still other procedures are selected by the surgeon that are performed in the base of the metatarsal bone (see surgeries performed in the base of the metatarsal).
Glossary of Terms
Bunion – Bump on the side of the foot at the base of the great toe
Bursitis – An inflammation of a fluid sac often found overlying a bunion
Fixation – Act of holding bones together, commonly require external devices such as pins, screws or plates
Hallux abductovalgus (HAV) – Medical term describing the deviation of the great toe toward the 2nd toe; common component of bunions
Metatarsal – A long bone of the foot that forms the ball of the foot
Orthoses – Surgical procedure that creates a cut in a bone to achieve realignment; a “surgical fracture”
Pronation – Motion of the foot which when excessive results in flattening of the arch; one possible cause of bunion formation
Toe box – Part of the shoe that covers the toes
About the Authors:
Kenneth W. Oglesby, D.P.M., Second-year podiatric surgical resident, Beth Israel Deaconess Medical Center, Boston, Mass.
John M. Giurini, D.P.M., Chief, Division of Podiatry, Beth Israel Deaconess Medical Center, Boston, Mass., Assistant Clinical Professor of surgery, Harvard Medical School, Boston, Mass.
