Three-dimensional Finit Element Analysis Of Children Proximal Femur Anatomy-type Plates

Background and ObjectiveFractures of proximal femur is common in adults, light violence can lead to fracture in the aged people for the reasons such as osteoporosis, and high-energy damage caused by road accidents do in the young people, so the study of biomechanics and design of implant about adult proximal femur is generally, the commonly-used internal fixation system treated in adult around femoral trochanter fracture includes proximal femur intramedullary nail(PFN), dynamia hip screw(DHS), dynamia condyle screw(DCS), and so on. But proximal femur fracture in children is relatively less in clinic, the reasons for reconstitution around femoral trochanter include the fractures of intertrochanteric and subtrochanteric of femoral in children, bone tumor around femoral trochanter (pathological fracture), coxa adducta orthopaedics in children. There is less study of biomechanics and invention of internal fixation aimed directely at proximal femur in children all over the world.With the full-speed development of traffic and increasingly-growing high-energy damage, the fractures around femoral trochanter are by no means rare, although the blood-transport is abundant in the position, the capability of union of fracture is better, and non-operation therapy can gain good effect, if①multiple injuries,②multi-portion fracture on the same limb,③open injury,④complicating impartant vascular nerve injuries,⑤pathological fracture,⑥expectant treatment failure appear, open reduction and internal fixation of plates will be the better choice, and with the advantages of therapy convenience, stable fixation and decrease of nursing cost price, it is easily accepted by families. Now there are hip screws and 95°dynamia condyle screw used specilly for proximal femur, angle plate of AO for coxa adducta orthopaedics on abroad, but there is no correlated products in our country. On account of the above-mentioned causes, a set of proximal femur anatomy-type plate in children is designed. It can both strengthen internal fixation and be consistent with biomechanics of proximal femur of Chinese children, what's more, biomechanics study of ex vivo sample have been carried out, getting the conclusion that its mechanics efficiency is better than reconstitution plates used in the past.To estimate mechanics efficiency of proximal femur anatomy-type plate in children better , and to compare with the biomechanics study of ex vivo sample to get to know if the design is reasonable and how to improve and optimize the next step, a three-dimensional finit element analogy of fomoral subtrochanteric fractures in children fixed with proximal femur anatomy-type plate in children is established, analyzing and discussing the consequence with FEM, evaluating the design of the plate.MethodsSCT scan a healthy boy selected to gain image data of proximal femur, fracture modle of proximal femur is established on the base of a three-dimision finit element model of proximal femur of healthy child is estabalished with Mimics10.01 digital 3D medical image interactive software and ANSYS10.0 finit element processing software; the three-dimision finit element modle of children proximal femur anatomy-type plate based on plate data is introducted the fracture modle to set bouncary and load condition and to carry out biomechanical analysis.ResultsThree-dimision finit element modles of fomoral subtrochanteric fractures and children proximal femur anatomy-type plate were established. Three-dimision finit element analysis of biomechanics was carried out, the results indicate that the design of children proximal femur anatomy-type plate is consistent with biomechanics priciple and can meet the need of fixation of proximal femur in children with the good intension, rigidity and constancy. ConclusionsIt is effective and feasible to establish a three-dimision finit element modle of children skeleton on the base of computer data from a living body with SCT tomoscan technique. The three-dimision finit element modles of children fomoral subtrochanteric fractures and children proximal femur anatomy-type plate are vivid and objective, and can reflect geometrical structure; it is for the first time to estimate the mechanics feature of internal fixation system in children limb fractures in our country. The result come out that the design of our internal fixation system is consistent with biomechanis principle and the stability, intensity and rigidity are reliable and can be used in clinic.