TANGENTIAL VIEW OF THE LISFRANC JOINT – A SIMPLE, NOVEL VIEW TO MINIMIZE THE INCIDENCE OF MISSED INJURY

Abstract

Introduction: Up to 20% of Lisfranc injuries can go unrecognised with resultant long-term morbidity. Spontaneous relocation may mask the injury. Standard AP, lateral and oblique views of the foot are the primary radiological views. Weight bearing views may not be possible acutely and stress views may require anaesthesia. The standard AP view does not show the tarso-metatarsal joint clearly with alignment of the medial border of the second metatarsal to the medial border of the intermediate cuneiform all important.

Materials and methods: We used a tangential AP view of the tarso-metatarsal joint taken by tilting the x-ray beam cephalad. The degree of tilt was dictated by the declination angle of the first metatarsal seen on the lateral view of the foot (20–25 degrees for most people). Sixteen patients had standard AP, lateral and oblique views of their foot at the time of injury and were not diagnosed to have a Lisfranc injury. They remained symptomatic for an average period of 5 weeks (range, 2 to 15 weeks) before they had the tangential view of the Lisfranc joint.

Results: In all 16 patients the first and second tarso-metatarsal joint and the first inter-metatarsal space were more clearly visible. Thirteen patients had abnormal findings to confirm the diagnosis of Lisfranc injury and for 2 surgical treatment would have been appropriate if identified earlier than 14 and 15 weeks respectively.

Discussion and conclusion: This view confirmed the diagnosis in 13 patients who would have otherwise been discharged as a minor soft tissue injury.

We have also used this view successfully for injecting local anaesthetic in the tarso-metatarsal joints to elucidate the exact source of pain.

We recommend this simple view should be routinely used in addition to the standard AP, lateral and oblique views of the foot for mid foot injuries.