Imaging Case of the Week 531 Answer

The foot x-ray shows

avulsion fracture of the base of the 2nd metatarsal (fleck sign) with mild widening of the joint space between 1st & 2nd metatarsals. A CT scan of the foot confirmed Lisfranc fracture dislocation. There is also a fracture involving the medial cuneiform bone.

Normally, in the AP view of the foot, medial margin of the 2nd metatarsal should align with the medial margin of the intermediate cuneifom bone as shown below (red line).

Normally in the oblique view, medial margin of the 3rd metatarsal should align with the medial margin of the lateral cuneiform as shown below (blue line).

The patient was referred to orthopaedician for further management.

Lisfranc injury is a missable fracture dislocation of the midfoot. Pay attention to the lines as mentioned above.

Reference: Fundamentals of Diagnostic Radiology by Brant and Helms.