Freiberg disease complicating unrelated trauma.

Freiberg's infraction is an avascular necrosis of the metatarsal head characterized by the development of disorderliness of chondrogenesis and osteogenesis in previously normal bone. Radiographic findings follow the pathological progression of bony changes. The presented cases document the development of avascular necrosis in a previously normal metatarsal that occurred after trauma or surgery elsewhere in the foot. It is suggested that infraction of the metatarsal head resulted from microfracture caused by abnormal stress.