The Design And Biomechanical Study Of Titanium Memory Alloy Three-corner Fixator

Objective:To design and produce a new kind of three-corner fixator which made of nickel-titanium memory alloy and measure the changes of plantar pressure of the The lateral column dislocation by three different implants(Nickel titanium memory alloy three-corner fixator,the bridge plate and 2mm K-wire)to provide experimental reference in selecting implants and evaluate the biomechanical properties of those implants.Provides the basis for its clinical application.Methods:By collecting CT scan imaging data of 60 cases(male 30 cases,30 cases of female)of healthy adult foot,provid the solid data to produce the fixator,then using CAD drawing software tools to design a suitable nickel titanium memory alloy three-corner fixator..six fresh foot specimens were made into the models of the lateral clumn dislocation,which were fixed with Nickel titanium memory alloy three-corner fixator,the bridge plate and 2mm K-wire in turn.After the loading of 600 N,the changes of the plantar pressure in forefoot were measured by the method of the Tekscan Evolution hanle pressure system.During the experiment axial compression,were performed with ElectroForce(?)3510series test instruments.The compression stiffness of each bone-fixation combination was calculated and statisticly analyzed.Results:While the tarsometatarsal joint fracture dislocation was fixated by those there dfferent kind of implants,the pressure under the fourth and fifth tarsometatarsal joints would all increased,the peak pressure under the second and third metatarsal head would all decrease,differences were statistically significant(P<0.05).Nickel titanium memory alloy three-corner showed no statistical significant difference compared with normal state(P>0.05).The compression stiffness of pre-treatment group B was showed statistically significant lower than that of group C(P<0.05),D(P<0.05),group E(P<0.05).There were no statistically significant between the compression stiffness of the there implants before fatigue test.The compression stiffness of K-wire group were decreased with significance.ConclusionConclusion:By measuring and drawing design,following the characteristics of material,we successfully designed and produced nickel titanium memory alloy three-corner.by biomechanical experiments,Nickel titanium memory alloy three-corner fixator,the bridge plate and K-wire showed differences in the ability to recover from foot pressure.It is proved that the axial compression ability of the three-corner fixator is good.Nickel titanium memory alloy three-corner fixator would help plantar pressure of the forefoot return to the normal state.The stability of the Nickel titanium memory alloy three-corner fixator is favor to meet the special biomechanical needs.