Bone excrescence at the medial base of the distal phalanx of the first toe: normal variant, reactive change, or neoplasia?

In a review of 157 anteroposterior (AP) foot radiographs in 117 adult and pediatric patients, we observed a medial excrescence on the plantar aspect of the terminal phalanx of the hallux in 88.5% of the feet. Histologic analysis documented the presence of reactive bone. The bony outgrowth appears after closure of the adjacent physeal plate and is rarely symptomatic. Its high prevalence indirectly implies that it is not specific to any particular type of foot. Although certain types of foot may contribute to its development, we believe that repetitive forces occurring during ambulation induce this reactive bone formation.