MRI of metatarsal head subchondral fractures in patients with forefoot pain.

OBJECTIVE

The purpose of our study was to determine the MRI features of metatarsal head subchondral fractures in symptomatic adults.

MATERIALS AND METHODS

A retrospective review of foot MRI procedures was performed to detect cases of metatarsal head subchondral fractures over a 6-year period. MR images of selected cases were analyzed by two reviewers for the presence of subchondral fracture, marrow edema-like pattern, metatarsal head flattening, and subchondral sclerosis. Patients with a history of foot surgery, infection, or inflammatory arthritis were excluded. Assessment for coexisting osseous and soft-tissue abnormalities was also performed.

RESULTS

Subchondral fractures of the metatarsal heads were seen in 14 patients. All patients were women. The metatarsal head most commonly affected was the second (71%, 10/14) and the dorsal third of the metatarsal articular surface was involved in 79% (11/14). MRI findings of subchondral fracture of the metatarsal head with severe marrow edema-like pattern were seen in 71% (10/14), suggesting early stage changes. Metatarsal head collapse with subchondral sclerosis and mild or absent marrow edema-like pattern were seen in 29% (4/14) indicating late-stage changes. Concurrent abnormalities included three patients (21%) with metatarsal shaft fractures and one patient (7%) with an interdigital neuroma. One subject was treated surgically.

CONCLUSION

Subchondral fractures of the metatarsal heads can be detected on MR examinations of adults with forefoot pain. A subchondral fracture with associated marrow edema-like pattern is the most common presentation and likely reflects early stages of metatarsal head infraction.