The Design And Biomechanical Comparison Of The Elastic Hook Plate Of Lower Tibiofibular Ligament Union

Objective: To research biomechanical property of the elastic hook plate of lowertibiofibular ligament union, and to compare the micromovement of distal tibiofibularjoints under the influence of applying different internal fixations.Methods: Eight pairs of fresh cadaveric legs with intact ligaments were tested inaxial compression(500N), four detection marks of laser scanner were installed nearthe highest point in medial malleolus and lateral malleolus. The normal group’smovement of detection marks on the position of neutrality, dorsiflex, plantar-flexion,varus and eversion of ankle joint were scanned by3D laser scanner．The movementof detection marks on the X, Y and Z-axis (X-axis stands for the vertical axisbetween coronal plane and Z-axis; Y-axis stands for the vertical axis betweensagittal plane and Z-axis; Z-axis stands for macroaxis of tibia).Then we sectionedthe lower tibiofibular syndesmosis. Ankles were successively repaired with theelastic hook plate of lower tibiofibular ligament union, engevlbrecht syndesmosishook and a AO screw through there-cortices. The elastic hook plate of lowertibiofibular ligament union group’s, engevlbrecht syndesmosis hook group’s and AOscrew group’s movement of detection marks were tested under the above condition,respectively.Results:①The displacement comparison of the distal tibiofibular joints on theX-axis and Y-axis: There was no significant difference in normal group or the elastichook plate of lower tibiofibular ligament union group(P>0.05).There was significantdifference in normal group, engevlbrecht syndesmosis hook group and AO screwgroup(P<0.05). There was significant difference in the elastic hook plate of lowertibiofibular ligament union group, engevlbrecht syndesmosis hook group and AOscrew group(P<0.05).②The displacement and rotation angle comparison of thedistal tibiofibular joints on the Z-axis: There was no significant difference in normalgroup, the elastic hook plate of lower tibiofibular ligament union group orengevlbrecht syndesmosis hook group(P>0.05). There was significant difference in normal group and AO screw group(P<0.05). There was significant difference in theelastic hook plate of lower tibiofibular ligament union group and AO screwgroup(P<0.05). There was significant difference in engevlbrecht syndesmosis hookgroup and AO screw group(P<0.05).Conclusion：The elastic hook plate of lower tibiofibular ligament union is adynamic instrument conform the biomechanical characteristics of normal distaltibiofibular joint. This implant can stabilize the ankle mortise, and at the same timeallow early mobilization and physiologic micromotion as the ligament union andsoft tissues heal. Therefore, the elastic hook plate of lower tibiofibular ligamentunion better than the other internal fixation methods, This implant is an idealinternal fixation.