Bunion (hallux valgus)

A bunion — medically called hallux valgus — is a progressive deformity in which the great toe angles toward the lesser toes and the first metatarsal head drifts medially, creating a bony prominence. The deformity involves the entire first ray: metatarsophalangeal joint subluxation, sesamoid displacement, pronation of the great toe, and secondary crowding of the lesser toes. Narrow footwear accelerates progression in genetically predisposed individuals.

Most patients are women (8:1). Symptoms include bunion pain with footwear, callus formation, and sometimes lesser toe deformity.

Weight-bearing AP and lateral foot X-rays quantify the hallux valgus angle (HVA) and first-second intermetatarsal angle (IMA), which guide the appropriate surgical correction. Sesamoid position and first TMT joint stability (for Lapidus procedure candidacy) are assessed.

Surgery is indicated for symptomatic bunions that have failed footwear modification and accommodation. Pain — not cosmesis — is the indication for surgery.

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