Bunion (hallux valgus)

A bunion (medically hallux valgus) is a slowly worsening deformity at the base of your big toe. The big toe drifts toward the smaller toes while the long bone behind it pushes the other way — leaving a bony bump on the inside of your foot. It's not just a bump: the whole first ray of the foot rotates and shifts, often crowding the smaller toes too. Narrow footwear speeds the process up in people who are genetically prone to bunions.

Most patients are women (about 8 to 1). Typical symptoms are pain at the bony bump from shoe pressure, calluses on the bottom of the foot, and sometimes secondary deformities in the smaller toes from the crowding.

The most obvious sign is the bony bump on the inside of your foot at the base of the big toe. The bump itself may be red, swollen, and tender from rubbing against your shoe. Over time the big toe drifts further toward — and sometimes over or under — the second toe, crowding it out of its normal position and sometimes causing a secondary hammer toe or crossover toe deformity.

Pain is usually worst in shoes, especially narrow or pointed styles that press against the bump. You may develop a thick callus under the ball of your foot as weight shifts off the big toe onto the smaller metatarsal heads (transfer metatarsalgia). Many patients also notice the foot getting wider, making it harder to find shoes that fit comfortably.

Standing X-rays measure the angle of the deformity (called the hallux valgus angle) and the spread between the first two long foot bones (the intermetatarsal angle). Both numbers guide which type of surgical correction would work best. Your surgeon also looks at the position of the small bones under the big toe joint and how stable the joint at the base of the foot is — both factor into the decision.

Surgery is for painful bunions that haven't responded to footwear changes and padding. Important: pain — not how it looks — is the reason to operate. There are several procedures, and the right one depends on the angles measured on your X-rays.

External patient-education references and related OSI pages for additional background:

• Britannica — Bunion
• Britannica — Ankle (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language