Papers by Keyword: Internal Fixation

Abstract: This paper deals with the difference of finite element analysis of results between distinguishing bone materials modeling and single bone material modeling. The computed tomography (CT) data was used to build the model that can distinguish cortical bone, cancellous bone of the femur model, together with the plates could be used to set up internal fixation system and do the finite element analysis. The results indicated that the distributions of stress and strain were basically the same, so were the location of the maximum stress and strain. While, except under the axial loads the value of maximum stress and the value of maximum strain showed significant differences. Finally, study reached the conclusion that under the axial loads there were no significant difference between the two methods, thus the single bone material model could be used for easier computing, while, under the other 4 consequences paper recommended distinguishing bone material method for more practical results.

Abstract: To provide the doctors a basis for treating sacral fractures and offer optimal surgical program, three-dimensional (3D) finite element method was used to simulate normal pelvis and the unstable pelvis sufferedIsection, IIsection and III section sacral fracture respectively.The unstable pelvises were respectively fixed with five different internal fixation implants types, which are respectively rectangular plate with cannulated screw, rectangular plate with solid screw, expansile bolt, convex plate with cannulated screw, convex plate with solid screw. The stress distribution and the X, Y, Z direction displacement of the sacrum were calculated for each sacral fracture treatment of five internal fixation implants after giving 500N axial load on lumbar vertebra and were compared with the normal pelvis, then the optimal surgery program were determined. After the analysis, by comparing the five combinations for each sacral fracture treatment of five internal fixation implants, the preferred combinations for the reset treatment of theIsection sacral fractures were rectangular plate with cannulated screw and convex plate with cannulated screw; The preferred combination for the reset treatment of the II section sacral fractures was expansile bolt; The preferred combination for the reset treatment of the III section sacral fractures was convex plate with cannulated screw.

Abstract: The spine, which is throughout the trunk, is of great importance to the skeleton structure of human beings. For spine is vulnerable, the rate of spine incident trauma injury is relatively high. In the contemporary technology, the internal fixation prosthetics with implanting pedicle screws is the most efficient way in clinical treatment. However spine internal fixation surgery has many disadvantages like complex in the operation, the high penetration rate and inability to be used in the field battle. As a result, according to the magnetic property difference of different vertebra tissues, an eddy current detection method which is used in localization and recognition of different vertebra tissues to realize the navigation of spine internal fixation surgery is proposed in this paper. A set of improved series-reverse-three coils eddy current sensor is used to test the NaCl solution which electrical conductivity matches that of biological tissue. And the result of several experiments indicates this method can detect the biological tissue with the electrical conductivity no less than 0.5 S/m, which lays a solid foundation to further study of recognition different vertebra tissues.

Abstract: A three-dimensional finite element model is developed to simulate the integrated system which consists of the fractured bone (femur), bone plate and stabilization screw by using the ANSYS software. The stress and strain distribution of the integrated system is investigated. The numerical model simulates a patient’s imperfect walking under the assumption that the fractured bone is not able to support any load and all body weight was burden by bone plate in fractured bone section. The simulation results reveal that the maximum Von Mises stress on bone plate is much less than yield strength and fatigue strength of Titanium alloy.