Anatomy and biomechanical study of the Lisfranc ligament

Abstract

Objective To investigate the anatomy of Lisfranc ligament and the mechanical properties of different fixations of the ruptured ligament.Methods In 44 fresh frozen foot specimens,the Lisfranc ligaments were dissected for morphological observation.Next the specimens were randomized into 4 equal groups (n =11) before the Lisfranc ligaments were ruptured.In group A the ligament was intact; in groups B,C and D,the medial cuneiform bone and the second metatarsal bone were fixated after reduction along the ruptured ligament respectively with a 2.0 mm Kirschner wire,a 3.0 mm hollow screw and a 4.0 mm hollow screw.The mechanical properties in each group were determined with a CSS-44020 biomechanical testing machine.The mechanical data were statistically analyzed.Results The dimensions of Lisfranc ligament were 10.05 mm in length,7.03 mm in width and 3.30 mm in thickness.In terms of the maximum tensile strength,total energy and stress upon rupture,group A was the strongest,followed by group D,next by group C and last by group B.In terms of the maximal strength and tensile stress,groups A and D were significantly different from groups B and C (P ＜ 0.05) and group B was significantly different from group C (P ＞ 0.05).Conclusions Anatomical reduction and internal fixation along the Lisfranc ligament with a 4.0 mm hollow screw can reconstruct the ruptured Lisfranc ligament and contribute significantly greater to the stabilization of the second metatarsal to the first cuneiform than fixations with a 2.0 mm Kirschner wire or a 3.0 mm hollow screw.A gasket can improve the strength of fixation. Key words: Foot; Ligament; Anatomy; Biomechanics