Persistent instability in pure ligamentous Lisfranc joint injuries.

ABSTRACT

INTRODUCTION: Lisfranc injuries refer to a specific group of injuries which lead to instability of the tarsalmetatarsal joint. Our hypothesis is that persistent instability is permanent and asymptomatic in subtle unstable injuries of the medial column which have been fixed percutaneously. OBJECTIVE: To describe the persistent instability of pure ligamentous Lisfranc joint injuries treated with anatomic reduction and percutaneous screws fixation by comparative radiographs of both feet. MATERIALS AND METHODS: Between 2014 and 2018, 14 patients diagnosed with subtle unstable Lisfranc injury were evaluated. Indications for surgery included widening (diastasis) greater than 2mm between the first and second metatarsal bases, and subluxation greater than 1mm of a metatarsal base from its respective tarsal bone. RESULTS: Persistent instability was found on the stress radiographs of 11 patients (78.57% 95% CI 48.60-95.07%) but without clinical connotations. The average AOFAS score evaluated at 18 months post-operatively was of 97.14 (SD±4.68) points. The median follow-up was 24 (RIQ 18-24) months. In all patients, anatomical reduction on radiographs was evident. CONCLUSION: We observed a persistent instability of the Lisfranc joint, without clinical connotations. Subtle unstable Lisfranc injuries treated with percutaneous screw fixation have a good clinical and functional outcome. LEVEL OF EVIDENCE IV.