Stress fractures of the metatarsal heads.

OBJECTIVE: To describe the imaging characteristics of stress fractures of the heads of the metatarsal bones, emphasizing their difference from the more common metatarsal shaft and neck stress fractures.

DESIGN AND PATIENTS: Eight patients with stress fractures of the head of one or more of the metatarsal bones were seen in a 5-year period. The four men and four women were 31-72 years of age (mean 52.3 years). Three of the patients were active in sports. Three patients had underlying conditions predisposing to insufficiency fracture and one patient had had a bunionectomy on the affected foot 5 years previously. Plain radiographs and magnetic resonance (MR) imaging studies were reviewed in a retrospective feature.

RESULTS: Plain radiographs showed subchondral sclerosis of the metatarsal heads in all but one case, in which MR imaging, performed 6 weeks after the onset of symptoms, demonstrated an area of abnormal signal intensity in the head of the third metatarsal bone consistent with marrow edema.

CONCLUSION: Stress fractures (i.e., fatigue and insufficiency fractures) of the head of the metatarsal bones occasionally occur. Because of their less recognized appearance on routine radiographs and MR images, they are frequently overlooked.