A bunion is a deformity that usually occurs at the end of one of the five long bones (the metatarsal bones) that extend from the arch of the foot and connect to the toes. Most often bunions develop in the first metatarsal bone (the one that attaches to the big toe). A bunion may also develop in the bone that joins the little toe to the foot (the fifth metatarsal bone), in which case it is known as either a bunionette or a tailor's bunion.
A bunion typically develops in the following way:
- The big toe or the fifth ("pinky") toe is forced in toward the other toes, causing the head of the metatarsal bone to jut out and rub against the side of the shoe.
- A bunion begins to form when the big or little toe is forced in toward the rest of the toes, causing the head of the metatarsal bone to jut out and rub against the side of the shoe.
- The underlying tissue becomes inflamed, and a painful bump forms.
- As this bony growth develops, a bunion is formed as the big toe is forced to grow at an increasing angle toward the rest of the toes. One important bunion deformity, hallux valgus, causes the bone and joint of the big toe to shift and grow inward, so that the second toe crosses over it.
People born with abnormal bones in their feet are more likely to form a bunion. In addition, wearing narrow-toed, high-heeled shoes, which put enormous pressure on the front of the foot, may also lead to a bunion formation. The condition may become painful as extra bone and a fluid-filled sac grow at the base of the big toe.
Flat feet, gout, arthritis, and occupations (such as ballet) that place undue stress on the feet can also increase the risk for bunions.
Shoes and Protective Pads. Pressure and pain from bunions and bunionettes can be relieved by wearing appropriate shoes, such as the following:
- Soft, wide, low-heeled leather shoes that lace up
- Athletic shoes with soft toe boxes
- Open shoes or sandals with straps that don't touch the irritated area
A thick doughnut-shaped, moleskin pad can protect the protrusion. In some cases, an orthotic can help redistribute weight and take pressure off the bunion. Nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroid injections may offer some pain relief.
Surgery. If discomfort persists, surgery may be necessary, particularly for more serious conditions, such as hallux valgus. There are more than 100 surgical variations, ranging from removing the bump to realigning the toes.
The most common surgery, an office procedure known as bunionectomy, involves shaving down the bone of the big toe joint. In one procedure the surgeon uses a very small incision, through which the bone-shaving drill is inserted. The physician shaves off the bone, guided by feel or x-ray. This technique is not a cure, but patient satisfaction is high and results are long-lasting.
More extensive surgeries may be required to realign the toe joint. Although there are variations of each, they generally involve one or more of the following:
- Osteotomy (cutting and realigning the joint). Long-term studies on osteotomies report that 90% of patients are satisfied with the procedure.
- Exostosectomy (removal of the large bony growth). This technique is only useful when there is no shift in the toe bone itself.
- Arthrodesis (removal of damaged portion of the joint, followed by implantation of screws, wires, or plates to hold the bones together until they heal). This is the gold standard procedure for very severe cases or when previous procedures have failed. Most patients report good results.
- Arthroplasty (removal of damaged portion of the joint with the goal of achieving a flexible scar). This technique offers symptom relief and faster rehabilitation than arthrodesis, but it can cause deformity and some foot weakness. Arthroplasty tends to be used in older patients. Biological or synthetic implants for supporting the toes are showing promise as part of this procedure.
- Tendon and Ligament Repair. If tendons and ligaments have become too loose, the surgeon may tighten them.
In severe cases, surgeons are testing bone grafts to restore bone length in patients who have had previous bunion surgeries or damage from osteoarthritis.
Complications, though uncommon in even the most complex procedures, can include:
- Continued pain
- Possible numbness
- Irritation from implants used to support the bone
- An excessively shortened metatarsal bone
Recovery from more invasive procedures, such as arthrodesis or osteotomy, may take 6 - 8 weeks, and it can be that long before a patient can put full weight on the foot. In such cases, the patient will need to wear a cast or use crutches. Elderly patients may need wheelchairs.