A bunion is abnormal angulation of the great toe in the direction of the other toes, causing inflammation and damage to the first metatarsophalangeal (MTP) joint. Also called swelling of first metatarsophalangeal joint of hallux, it is characterized by rotated toe, toenail eversion, and an erythematous callus at the MTP joint due to friction and rubbing. The etiology of bunions is unknown, but they may be hereditary. In some instances, bunions are associated with inflammatory joint disease or cerebral palsy. Wearing narrow or ill-fitting shoes can exacerbate damage to the MTP joint.

Bunions are more common in women than men and occur in patients of all ages, primarily starting in adolescence through adulthood. They can lead to hammertoe of the second toe, synovitis, degeneration of cartilage and metatarsal heads, entrapped nerve, or unstable gait from shifting weight-bearing regions of the foot (rays).

Treatments call for consultation with a podiatrist and range from conservative (altered shoes, orthoses, use of splints, physical exercises, bunion pads, applying ice, and NSAID pain relief) to surgical intervention (osteotomy, arthroplasty, arthrodesis, tenotomy, and bunionectomy).