Fractures of the anterosuperior calcaneal process can be both clinically and radiographically difficult to detect yet, if not recognized and immobilized early, may result in painful nonunion. The purpose of this study was to show that MR imaging is sensitive in the detection of such subtle or radiographically occult fractures, that the pattern of marrow edema corresponds to the two known mechanisms of injury, and that MR imaging can document both healing and nonunion of these fractures.

MR imaging can reveal subtle or nondisplaced fractures of the anterosuperior calcaneal process. Also, MR imaging can be used to document healing. The pattern of marrow edema limited to the anterosuperior calcaneal process corresponds to the bifurcate ligament avulsion mechanism of injury. Edema in both the anterosuperior calcaneal process and the cuboid is caused by the impaction mechanism of injury.