Late Onset Osteonecrosis of the Proximal Phalanx of the Great Toe in a Child.

Osteonecrosis, also known as avascular necrosis or osteochondrosis, refers to the death of bone tissue resulting from a to lack of blood supply. Osteonecrosis of the foot is most commonly seen in the talus and metatarsals and not as frequently in other bones. We report an extremely rare case of late-onset osteonecrosis of the proximal phalangeal head of the great toe in a 9-year-old male. Plain radiographs and computed tomography did not show any findings of osteonecrosis initially. However, because of persistent pain at the interphalangeal joint of the first toe and a decrease in the range of movement at the interphalangeal joint at 7 months after injury, the patient underwent additional examination with repeated radiographs and magnetic resonance imaging. We diagnosed late-onset osteonecrosis as a result of a subtle traumatic type I dislocation. Conservative treatment led to spontaneous recovery, leaving a bony fragment in the interphalangeal joint. To our knowledge, this is the first report of late-onset proximal phalangeal osteonecrosis after trauma in the great toe.