By Shahid Punwar, Rohit Madhav
Department of Trauma and Orthopaedic Surgery, University College Hospital , London , UK

Reprinted with permisssion from Injury Extra (2007), 38, 250-254.

Case history

We present a case of a 49-year-old lady who presented to the emergency department following an acute injury to her left foot the night before. The patient could not recall the exact mechanism of injury, but remembered stepping off a raised surface onto her left foot, and feeling sudden, severe pain.

Clinical examination revealed moderate swelling over the dorsal aspect of the foot in the region of the tibialis anterior insertion. The patient was diffusely tender to palpation over the midfoot, and unable to fully weight-bear.

Plain foot radiographs did not reveal any significant abnormality on initial review (Figure One). Specifically, there was no loss of alignment at the tarsometatarsal joints indicating a Lisfranc-type injury. These findings were corroborated by the on-call consultant radiologist.

Due to the degree of swelling and pain, the patient was referred to a consultant foot and ankle surgeon with a suspected mid-foot sprain. The specialist identified maximal tenderness at the tarsometarsal articulations, and arranged an urgent MRI scan (Figure Two).

MRI showed intra-articular fractures of the base of the second and fourth metatarsals, with some high signal in the Lisfranc ligament, which appeared otherwise intact. In addition, bone marrow oedema was seen within the lateral cuneiform, second metatarsal base and cuboid bones.

Retrospective review of the plain radiographs taken on presentation showed a cortical break at the base of the fourth metatarsal that was partially obscured by the overlapping bones in that area. No evidence of injury to the second metatarsal could be found on reviewing the initial radiographs.

Treatment was conservative in a below-knee orthotic with strict heel weight-bearing only.

Had this injury not been identified, the patient may have started to weight-bear too early, leading to possible displacement and the need for operative intervention.