Do columns or sagittal displacement matter in the assessment and management of Lisfranc fracture dislocation? An alternate approach to classification of the Lisfranc injury.

AIM: The classification of a Lisfranc injury has conventionally been based around Myerson's system. The aims of this study were to review whether a novel classification system based on sagittal displacement of the tarsometatarsal joint and breadth of injury as determined by a columnar theory was associated with functional outcomes and thus had a greater utility. PATIENTS: We retrospectively reviewed 54 Lisfranc injuries with a minimum follow up of two years at our Level One Trauma Centre. Each fracture was sub-classified based on our novel classification system which assessed for evidence of sagittal displacement and involvement of columns of the midfoot. Our primary outcome measures were the FFI and AOFAS midfoot scores. RESULTS: Injuries involving all three of the columns of the midfoot were associated with significantly worse functional outcome scores (FFI p=0.004, AOFAS p=0.036). Conversely, sagittal displacement, whether dorsal or plantar, had no significance (FFI p=0.147, AOFAS p=0.312). The best predictor of outcome was the quality of anatomical reduction (FFI p=0.008, AOFAS p=0.02). CONCLUSION: Column involvement and not sagittal displacement is the most significant factor in considering the severity Lisfranc injury and long term functional outcomes. This classification system has greater clinical utility than those currently proposed.