Introduction

A bunion, or hallux valgus, is a condition that affects the joint at the base of the big toe. The bunion actually refers to the bump that grows on the side of the first metatarsophalangeal (MTP) joint (Fig. 1). However, the condition is actually much more complex than a simple bump on the side of the toe.

Anatomy

The term hallux valgus actually describes what happens to the big toe. Hallux is the medical term for the big toe (Fig. 2). Valgus is an anatomic term that means the deformity goes in a direction away from the midline of the body. So, with hallux valgus, the big toe begins to point towards the outside of the foot. As this condition worsens, other changes occur in the foot that increases the problem. The bone just above the big toe, the first metatarsal, usually develops too much of an angle on the inside edge of the foot (Fig. 3). The bunion is actually a response to the pressure from the shoe on the point of this angle.

Causes

Many foot problems occur because of abnormal pressure or rubbing. At first a bump made up of irritated, swollen tissue may form that is constantly caught between the shoe and the bone beneath the skin. The constant pressure may cause the bone to thicken as well, creating an even larger lump. Any prominence, or bump, in the bone will make the situation even worse over the bump. Skin responds to constant rubbing and pressure by forming a callous. The soft tissues underneath the skin respond to the constant pressure and rubbing by growing thicker. Both the thick callous and the thick soft tissues under the callous are irritated and painful. In order to reduce the pain, the pressure must be decreased as well. Changing the pressure from the shoes can reduce the outside pressure. The inside pressure can be reduced by surgically removing any bony prominence.

Symptoms

The symptoms of hallux valgus usually center on the bunion. The bunion is painful. The severe hallux valgus deformity is also a distressing cosmetic problem to many. Finding appropriate shoe wear can become difficult, especially for women who desire to have the latest in shoe styles. Finally, increasing deformity begins to displace the second toe upward and may create a situation where the second toe is constantly rubbing on the shoe.

Diagnosis

Diagnosis begins with a careful history and physical examination by your doctor. This will usually include a discussion about shoe wear and the importance of shoes in the development and treatment of the condition. X-rays will probably be suggested. This allows your doctor to measure several important angles made by the bones of the feet to help determine the appropriate treatment.

Conservative Treatment

Treatment of hallux valgus or bunions nearly always starts with adapting shoe wear to fit the foot. In the early stages of hallux valgus, converting from a pointed toe shoe to a wider box-toe shoe may help stop the progression of the deformity. Since the bunion pain is due to pressure from the shoe, treatment focuses on removing the pressure. Bunion pads may also reduce pressure and rubbing from the shoe. There are also numerous devices, such as toe spacers, that attempt to splint the big toe and reverse the deformity.

Surgical Treatment

If all conservative measures fail to control the symptoms, then surgery may be suggested to treat the bunions. Well over one hundred surgical procedures exist to treat hallux valgus. The basic surgical procedure for hallux valgus can include removing the bunion, re-aligning the bones that make up the big toe, or balancing the muscles around the joint so the deformity does not return.

In some cases, surgery may only be required to remove the bunion. This operation is performed through a small incision on the side of the foot immediately over the area of the bunion. Once the skin is opened the bump is removed using a special surgical saw or chisel. The bone is smoothed and the skin incision is closed with small stitches.

Realignment of the big toe may also be necessary. The surgeon must decide if the metatarsal bone will need to be cut and realigned as well. This decision is based on the angle between the first metatarsal and the second metatarsal.

When a surgeon cuts and repositions a bone, it is referred to as an osteotomy. There are two basic techniques used to perform an osteotomy to realign the first metatarsal.

In some cases, the far end of the bone is cut and moved laterally (sideways) reducing the angle between the first and second metatarsal bones (Fig. 4). This procedure is called a distal osteotomy and usually requires one or two small incisions in the foot. Once the surgeon is satisfied with the position of the bones, the osteotomy is held in the desired position with metal pins (Fig. 5). Once the bone heals, the pin is removed. Metal pins are usually removed between three and six weeks following surgery.

In other situations, the first metatarsal is cut at the near end of the bone (Fig. 6). This procedure, known as a proximal osteotomy, usually requires two or three small incisions in the foot. The bone is realigned and held in place with metal pins until it heals. Again, this reduces the angle between the first and second metatarsal bones.

Realignment of the big toe is then completed by releasing the tight structures on outer side of the first MTP joint including the tight joint capsule and the tendon of the adductor hallucis muscle. (A joint capsule is tissue that surrounds a joint and isolates it from the rest of the body.) By releasing the tendon, the toe is no longer pulled out of alignment. The toe is realigned and the joint capsule on the side of the big toe closest to the other toe is tightened to keep the toe straight, or balanced (Fig. 7). The skin incisions are then closed with small stitches and a bulky bandage is applied to the foot.

Bunions: Rehabilitation

Following surgery, the bones and soft tissues may heal in about eight weeks. You may be placed in a wooden-soled shoe or a cast to protect the bones. You may also need crutches. A physical therapist can help you learn to use your crutches properly. You will probably wear a bandage or dressing for about a week following the procedure. The stitches will be removed after ten to fourteen days. If your surgeon used dissolvable stitches, they will not need to be removed. During your follow-up visits, X-rays may be taken so that the surgeon can follow the healing of the bones and determine how much correction has been achieved.